Method for making a continuous web from cellulose-based material.

Abstract

Method for making a continuous web (N) from cellulose-based material, comprising the steps of mixing a first quantity of at least one dry product with a second quantity of at least one liquid in a kneader (100) to obtain a mixture, said mixture having a moisture content less than 65%, in which said dry product comprises a cellulose content comprised between 20% and 80% and conductive particles, the latter consisting exclusively of particles of metallic material. The method includes a step of forming a continuous web (N) from said mixture and a step of drying said continuous web (N) to obtain a dry continuous web (N).

Description

[0001] DESCRIPTION

[0002] METHOD FOR MAKING A CONTINUOUS WEB FROM CELLULOSE- BASED MATERIAL

[0003] Technical field

[0004] The present invention relates to a method for making a continuous web from cellulose-based material and a method for making rod-shaped segments of the smoking article industry from the aforesaid continuous web. The present invention further relates to an article for generating aerosols.

[0005] Background art

[0006] Smoking articles which can be heated without burning for the purpose of generating an aerosol are known. Such smoking articles have a consumable portion or "plug" comprising strips obtained by cutting a web of plant-based material.

[0007] The term "plant-based” mixture means a plant-based material (in particular non-tobacco) processed by grinding or other similar procedure to modify the particle size thereof so as to promote subsequent mixing treatments thereof. In particular, it is intended that the continuous web is a semifinished product obtained by mixing and processing at least one dry plant component, such as cellulose or cellulose derivatives, rapeseed, hemp, straw or other varieties, hemp, aromatic leaves or still others, with a wet component, such as water and one or more additives.

[0008] During use, the plug is heated to generate the aerosol, and this is done without burning the plant-based material but by heating it above a predetermined temperature.

[0009] In particular, in the field pertaining to the present invention, it is known to inductively heat the plug for generating aerosol. To this end, it is known to disperse particles of conductive material, for example susceptible to heat by induction, inside the mixture (slurry) used to make the tobacco web, so as to obtain a paste in which such conductive particles are dispersed.

[0010] The known technology, although well operable, has several problems that limit the effectiveness and practicality thereof.

[0011] Firstly, the dispersion of conductive particles within the mixture may not be homogeneous. In fact, due to the consistency of the mixture, the particles of material susceptible to heat by induction (which typically have a high specific gravity with respect to the remaining components of the mixture) have the tendency to stratify, especially during the casting phase of the mixture. This compromises the uniform consistency of the mixture, negatively affecting the performance and efficiency of the inductive heating.

[0012] Secondly, due to the high presence of moisture, such a type of mixture requires considerable energy consumption during the drying process. The high temperatures and prolonged drying time not only impact the overall energy efficiency of the process but can also generate unwanted effects on the quality and properties of the plant-based material.

[0013] Again, a further disadvantage is represented by the fact that, in some known technologies, the plug of the article consists only partially of strips obtained by cutting a web containing the conductive particles, while the remaining part of the filling of the plug consists of strips of plant-based material obtained with conventional methodologies and free of inclusions of conductive material. Such features make the process for making the article globally very complex and expensive.

[0014] Object of the invention

[0015] In this context, the technical task of the present invention is therefore to provide a method for making a continuous web from cellulose-based material, a method for producing rod-shaped segments of the smoking article industry from the aforesaid continuous web as well as an article for generating aerosols which are free from the drawbacks present in the prior art. In particular, it is an object of the invention to provide a method for making a continuous web from cellulose-based material, a method for making rodshaped segments of the smoking article industry from the aforesaid continuous web, as well as an article for generating aerosols which ensure a homogeneous distribution of the particles of conductive material within the plug of the article itself.

[0016] A further object of the invention is to provide a method for making a continuous web from cellulose-based material, a method for making rodshaped segments of the smoking article industry from said continuous web, as well as an article for generating aerosols which are energy- and cost-efficient.

[0017] A further object is to provide a method for making a continuous web from cellulose-based material, a method for making rod-shaped segments of the smoking article industry from the aforesaid continuous web, as well as an article for generating aerosols which simplify the production process of the article itself.

[0018] The specified technical task and the specified objects are substantially achieved by a method for making a continuous web from cellulose-based material, a method for making rod-shaped segments of the smoking article industry from the aforesaid continuous web as well as an article for generating aerosols comprising the technical features set forth in the appended claims 1 , 6 and 8, respectively, and / or in one or more of the claims dependent thereon and / or in the appended description.

[0019] In particular, the Applicant has found that by making a mixture considered to be of the dough type, i.e., a mixture having a pasty or viscous consistency, more in particular moldable (which has a moisture content lower than 65% and a cellulose content between 20% and 80%), the dispersion of the particles of conductive material, in particular metallic material, is optimized. In fact, the consistency of such a type of mixture inhibits the stratification of the aforesaid particles, ensuring a correct homogeneity of the mixture itself, greatly improving the overall thermal conductivity.

[0020] Furthermore, the low moisture content of the mixture requires less energy during the drying process. This not only improved the overall energy efficiency, but also helped keep the desired properties of the plant-based material unchanged.

[0021] Furthermore, the dispersion of the particles in the solid phase together with the dry material, in particular powdered cellulose, improves the homogenization of the material by optimizing the subsequent mixing step with the liquid.

[0022] Further features and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of an embodiment of a continuous web from cellulose-based material, a method for making rod-shaped segments of the smoking article industry from the aforesaid continuous web as well as an article for generating aerosols.

[0023] Brief description of the drawings

[0024] Such a description will be presented below with reference to the accompanying drawings, provided by way of mere and thus non-limiting indication, in which:

[0025] - Figure 1 shows a diagrammatic view of an embodiment of a system for implementing the methods in accordance with the present invention;

[0026] - Figure 2 shows a sectional view of an embodiment of an article comprising a segment for generating aerosols in accordance with the present invention.

[0027] Detailed description of preferred embodiments of the invention

[0028] The method for making a continuous web from cellulose-based material and the method for making rod-shaped segments of the smoking article industry from the aforesaid continuous web, in accordance with the present invention, will now be described in an embodiment thereof with reference to a system used to implement them, indicated with the reference numeral 1 in Figure 1 .

[0029] In the present description, the term "cellulose-based" means a reconstituted material obtained by mixing at least one dry component containing cellulose with at least one liquid component, for example water. Preferably, but not limitedly, the material comprises a mixture of components in the dry phase, at least one of which is cellulose-based and preferably such that cellulose forms the major fraction thereof.

[0030] In accordance with the present invention, the method can include feeding a first quantity of at least one dry product, in fiber and / or in ground or powdered form, in a mixing volume "V" of a kneader 100 and feeding a second quantity of at least one liquid in the mixing volume "V" of the kneader 10OThe kneader 100 can be of any type as long as it is capable of mixing the solid and liquid components.

[0031] In accordance with a particularly advantageous embodiment, the kneader 100 has a batch operation. Preferably, the kneader is configured to operate on slurries having an overall weight comprised between 20 kg and 600 kg, more preferably comprised between 40 kg and 500 kg.

[0032] In accordance with alternative embodiments, the kneader 100 has continuous operation.

[0033] As regards feeding the first quantity, the expression "at least one dry product" is intended to mean mainly cellulose (in the forms envisaged) and, possibly, at least one additional dry product, for example in fibers, ground and / or powder, preferably in smaller quantities. In particular, the additional dry product can comprise tobacco, rapeseed, hemp, straw or other varieties, hemp, cocoa, aromatic leaves or still others.

[0034] In accordance with a particularly advantageous embodiment of the method, the cellulose is cellulose in fibers and / or in ground or powdered form. Preferably, the cellulose comprises a powder component comprised between 10% and 100% by weight of the total cellulose. "Powder" means a material with a particle size less than 200 pm. Preferably, the at least one dry product comprises a cellulose content comprised between 20% and 80%, preferably comprised between 35% and 60%, even more preferably comprised between 40% and 55%.

[0035] The at least one dry product further comprises conductive particles consisting exclusively of metallic particles.

[0036] In other words, the conductive particles consist solely of metallic particles (i.e., they do not comprise graphite- and / or carbon- and / or mineral- based particles).

[0037] Preferably, the metallic particles have a particle size lower than 30 pm. More preferably, the particles having a particle size lower than or equal to 15 pm (D90). In accordance with an embodiment, the particles have a particle size equal to 10 pm.

[0038] In order to feed the first quantity of at least one dry product, the system 1 comprises a feeding line 120 for the at least one dry product, connected to the kneader 100.

[0039] If one or more additional dry products are included, the feeding line 120 can comprise a plurality of feeding branches 121 , 122, each dedicated to a particular dry product.

[0040] The feeding line 120 can further comprise an intermediate tank 123, operatively arranged upstream of the kneader 100 and connected to the kneader 100 by means of a delivery branch 124, where the dry products are pre-loaded and pre-dosed. A pre-mixing of the at least one dry product inside the intermediate tank 123 can be included.

[0041] As regards feeding the second quantity, the expression "at least one liquid" means mainly water and, preferably, at least one additional component preferably premixed with water. In particular, the additional component comprises one or more of glycerin, nicotine, lactic acid, propylene glycol, dyes, at least one binding agent. In order to feed the second quantity of at least one liquid, the system 1 comprises a feeding line 110 for the at least one liquid, connected to the kneader 100. If one or more of the aforementioned additional dry products are included, the feeding line 110 can comprise a plurality of feeding branches 111 , 112, each one dedicated to a particular liquid component.

[0042] The feeding line can further comprise an intermediate tank 113, operatively arranged upstream of the kneader 100 and connected to the kneader 100 by means of a delivery branch 114. Inside the intermediate tank 113, the water and the additional components are pre-loaded and pre-dosed. Preferably, the intermediate tank 113 is provided with mixing means configured for mixing the water with the one or more additional components.

[0043] According to an exemplary embodiment, the feeding of the first quantity of at least one dry product into the kneader 100 is first envisaged. In accordance with such an embodiment, a pre-mixing of the at least one dry product within the kneader 100 may be envisaged prior to feeding the second quantity of at least one liquid.

[0044] According to a further exemplary embodiment, the feeding of the second quantity of the at least one liquid is operated at least partially or entirely, before feeding the first quantity of the at least one dry product.

[0045] According to a further exemplary embodiment, regardless of the order of feeding the at least one dry product and the at least one liquid, the second quantity of the at least one liquid can be operated in two or more successive steps during the mixing of the mixture itself.

[0046] It is clear that the first quantity of dry product and the second quantity of a liquid can be fed into the mixing volume "V" simultaneously, possibly with a pre-mixing of the first quantity of dry product carried out outside the kneader 100. The method includes a step of mixing the first quantity of dry product with the second quantity of liquid in the kneader 100, obtaining a mixture with moisture content lower than 65% and a cellulose content comprised between 20% and 80%, preferably greater than 20%, even more preferably comprised between 35% and 60%, even more preferably comprised between 40% and 55%. Such a mixture can be considered of the dough type, having a pasty or viscous consistency, more in particular moldable and suitable for processing in a paddle kneader, or the like.

[0047] Advantageously, such a technical feature allows optimizing the dispersion of the metallic particles, i.e., of the conductive particles. In fact, the consistency of such a type of mixture inhibits the stratification of the aforesaid particles, ensuring a correct homogeneity of the mixture itself, greatly improving the overall performance, in use, of the (preferably inductive) heating, or improving the overall thermal conductivity.

[0048] Preferably, the mixture obtained has a moisture content (by weight) comprised between 15% and 65%, preferably comprised between 20% and 40% and more preferably between 25% and 35%. Using such moisture content ranges, it was found that the mixture produced by mixing can have a sandy and / or granular structure, for example with a particle size between 1 and 6 mm.

[0049] Preferably, regardless of the specific quantity of moisture (as long as it is less than 65%), the mixture obtained has a cellulose content between 20% and 80%, preferably greater than 20%, even more preferably between 35% and 60%, even more preferably between 40 and 55%, even more preferably equal to about 50%.

[0050] Preferably, regardless of the specific quantity of moisture content and cellulose content (as long as they are respectively lower than 65% and between 20% and 80%), the mixture obtained has a content of the aforesaid particles, by weight, comprised between 3% and 30%, preferably comprised between 5% and 20% and more preferably equal to about 8%. Once the kneading step is finished, the method includes forming the aforesaid continuous web "N" from the mixture itself, by lamination.

[0051] The step of forming the web "N" first includes carrying out at least one vertical lamination of the mixture by means of a vertical lamination unit 2 provided with at least one pair of rollers 201 , 202, 301 , 302, obtaining a laminated semi-finished product, which is released on a support 4, preferably a conveyor, configured to convey the laminated semi-finished product from the vertical lamination unit 2 to a horizontal lamination unit 3, where, subsequently, a horizontal lamination of the laminated semifinished product is carried out, thus obtaining a wet continuous web "N". Finally, the continuous web "N" is dried to obtain the aforesaid continuous web "N".

[0052] Structurally, the vertical lamination unit 2 comprises at least a first vertical lamination stage 200 comprising a respective pair of lamination rollers 201 , 202.

[0053] Preferably, the vertical lamination unit 2 comprises at least a first vertical lamination stage 200 and one or more subsequent vertical lamination stages 300, where each vertical lamination stage 200, 300 comprises a respective pair of lamination rollers 201 , 202, 301 , 302. In such embodiments, the laminated mixture from the first vertical lamination stage 200 is fed by gravity or by transport to the subsequent vertical lamination stages 300. One or more scraping tools 400, such as blades, can also be included, operatively connected to the rollers of each vertical lamination stage 200, 300, which are configured to carry out the aforesaid scraping.

[0054] In fact, it has been noted that, in the case of cellulose-based slurries and in particular with specific percentages of moisture content and cellulose fraction (such as to make the structure of the aforesaid mixture sandy and / or granular), the laminated semi-finished product exiting the first vertical lamination stage 200 has a discontinuous shape, in particular in the form of flakes.

[0055] The term "flake shape" in the present description means a semi-finished product broken into a plurality of fragments of irregular shape and having a plate-like conformation (i.e., extending substantially on a plane) and adhering to the surface of the roller.

[0056] Therefore, the second vertical lamination stage 300 has the function of collecting such flakes and re-laminating them, obtaining a continuous laminated semi-finished product. Downstream of the vertical lamination, the aforesaid horizontal lamination is then carried out so as to obtain a continuous web "N".

[0057] To this end, the horizontal lamination unit 3 comprises at least one horizontal lamination stage 500, provided with a respective pair of rollers 501 , 502. Preferably, the horizontal lamination unit 3 is a multistage lamination unit having two or more stages 500, each comprising a respective pair of rollers 501 , 502 configured to achieve a controlled reduction of the thickness of the continuous web "N" until having a calibrated thickness value. To this end, the horizontal lamination unit 3 comprises a plurality of pairs of horizontal rollers 501 , 502 arranged in series, which pairs of rollers 501 , 502 delimit an increasingly narrow passage therebetween to gradually reduce the thickness of the continuous web "N".

[0058] Once the continuous web "N" is made, the method then comprises the aforesaid drying step to obtain a dry continuous web "N". To this end, the system can comprise a drying device 600. The drying device 600 can be provided with one or more drying stages arranged in series so as to optimize the control of the process conditions (temperatures, humidity) of the drying step.

[0059] Advantageously, the low moisture content of the slyrry requires less energy during the drying process, improving the overall energy efficiency and also contributing to maintaining the desired organoleptic properties of the plant-based material.

[0060] In the following, the method for producing rod-shaped segments "B2" of the smoking article industry will be described with reference to the system 1 used to implement it.

[0061] The method includes a step of feeding the dry continuous web "N" obtained by the method described above, which has a multiple width. Preferably, the longitudinal cutting into strips of the continuous web "N" is included, so as to obtain a continuous web "SN" of single width. The method includes a subsequent step of crimping and / or cutting the continuous web "SN" into strips and / or discrete portions according to parallel longitudinal lines and / or portions. However, it is evident that the web processed by crimping or cutting can also be the entire web "N" exiting the drying device 600.

[0062] To this end, the system 1 comprises a cutting or crimping unit 700 provided with cutting tools 501 , such as rotating blades or rollers provided with side-by-side circumferential ridges, configured to crimp and / or cut the continuous web "SN". According to the known technology, the crimping or cutting is carried out by using different crimping or cutting rollers, the external profile of which is configured according to the purpose.

[0063] The method comprises a subsequent step of collecting the crimped or cut web and wrapping it in a wrapping strip "S", preferably of paper, to make a continuous rod "B1".

[0064] To this end, the system 1 comprises a forming unit 800, in particular provided with a forming beam of known type.

[0065] Advantageously, the filling of the continuous rod "B1" is entirely obtained by means of the aforesaid continuous web "N" made with the method described above.

[0066] The method comprises a subsequent step of cutting the continuous rod "B1" into segments "B2". In other words, by cutting the continuous rod "B1" into segments "B2", the consumable portions or "plugs" for the smoking article intended for generating aerosol are obtained.

[0067] To this end, the system 1 comprises a secondary cutting unit 900 provided with cutting tools, such as rotating blades, configured to transversely cut the continuous rod "B1" in a cadenced manner so as to obtain segments "B2" of the same length.

[0068] The present invention further 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 shown by way of nonlimiting example in Figure 2. In particular, the article "A" has a proximal side, provided with a filtering segment "C", and a distal side, provided with an aerosol generating segment "B2". Such an aerosol generating segment "B" is preferably made by means of the aforesaid method for making rod-shaped segments "B2" of the smoking articles industry.

[0069] Specifically, the filter segment "C" comprises a support element "C1" and / or a cooling element "C2" and / or a filter tip "C3".

[0070] For example, the support element "C1 " can have a tubular structure.

[0071] For example, the cooling element "C2" can be made by means of a sheet collected in PLA material.

[0072] The aerosol generating segment "B2" comprises an outer tubular wrapping at least partially filled with a plurality of strips and / or portions made of cellulose-based material, where each strip and / or portion includes the aforesaid conductive particles of metallic material. Such particles of metallic material are embedded and / or dispersed in the cellulose.

[0073] In such an embodiment, since the filling of the outer tubular wrapping is entirely made with such strips and / or discrete portions, only cellulose- based strips and / or discrete portions including the particles of metallic material are present inside the outer tubular wrapping. In more detail, the outer tubular wrapping is filled exclusively with the strips and / or discrete cellulose-based portions, which have a homogeneous structure defined by the plant base (cellulose and any further plant components) in which the conductive particles of metallic material are dispersed. In such strips and / or discrete portions, the proportions of the content of cellulose, water and conductive particles of metallic material are defined by the execution modes of the method according to the invention, therefore in accordance with the description above.

[0074] The use of conductive particles consisting exclusively of metallic material (i.e., which do not comprise particles based on graphite and / or carbon and / or minerals) allows a better controllability of the overall thermal conductivity. Advantageously, during use, such a feature allows a homogeneous and efficient heating of the aerosol generating segment "B2". Advantageously, moreover, such a feature allows simplifying the production process of the article "A" itself. Throughout the previous description, the cellulose-based material can be replaced by a tobacco-based material, maintaining the same humidity features which characterize a “dough” mixture, as defined above. The other features of the method and the smoking article remain unchanged.

[0075] The present invention achieves the preset objects, eliminating the drawbacks of the prior art.

Claims

CLAIMS1. A method for making a continuous web (N) from cellulose-based material, comprising the following steps:- a step of mixing a first quantity of at least one dry product with a second quantity of at least one liquid in a kneader (100) to obtain a mixture, where said mixture has a moisture content of less than 65%; wherein said at least one dry product comprises a cellulose content of between 20% and 80% and conductive particles, the latter consisting exclusively of particles of metallic material;- a subsequent step of forming a continuous web (N) from the mixture;- a subsequent step of drying said continuous web (N) to obtain a dry continuous web (N).

2. The method according to claim 1 , wherein said mixture has a content by weight of said conductive particles of metallic material of between 3% and 30%, preferably between 5% and 20% and, more preferably, around 8%.

3. The method according to claim 1 or 2, wherein said conductive particles of metallic material have particle size less than 30 pm, preferably said particles having particle size less than or equal to 15 pm (D90), and still more preferably said particles having particle size equal to 10 pm.

4. The method according to any one of the preceding claims, wherein said cellulose is cellulose in fibre and / or in ground or powdered form, preferably said cellulose comprising a powder component of between 10% and 100% by weight of the total cellulose.

5. The method according to any one of the preceding claims, wherein said step of forming a continuous web (N) comprises at least one sub-step of subjecting the mixture to lamination.

6. A method for making rod-shaped segments (B2) of the smoking article industry, comprising the following steps:- feeding a continuous web (SN) corresponding to, or obtained by longitudinally cutting, the dry continuous web (N) made according to any one of the preceding claims;- crimping and / or cutting the continuous web (SN) along parallel longitudinal lines and / or in discrete portions;- gathering the crimped or cut web and wrapping it in a wrapping strip (S), preferably of paper, to make a continuous rod (B1 );- cutting the continuous rod (B1 ) into segments (B2).

7. The method according to claim 6, wherein the filling of said continuous rod (B1 ) is made entirely from said continuous web (SN), crimped and / or cut longitudinally or in discrete portions.

8. An aerosol generating article (A), comprising a plurality elements assembled to form a rod-shaped aggregate having a proximal side, provided with a filter segment (C), and a distal side, provided with an aerosol generating segment (B2), wherein said aerosol generating segment (B2) comprises an outer tubular wrapping filled with a plurality of cellulose-based strips and / or discrete portions, each strip and / or portion including conductive particles consisting exclusively of particles of metallic material.

9. The article (A) according to claim 8, wherein said conductive particles of metallic material are embedded and / or dispersed in the cellulose.

10. The article (A) according to claim 8 or 9, wherein said outer tubular wrapping is filled exclusively with said strips and / or portions of cellulose including the conductive particles of metallic material.

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