Method and apparatus for producing a sheet of aerosol-generating substrate for an aerosol-generating article

Abstract

A method for producing a sheet of aerosol-generating substrate for an aerosol-generating article, the method comprising: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent weight per weight and 35 percent weight per weight (w / w); then mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough (D) or a slurry (S); forming a sheet from the dough or slurry; drying the sheet to obtain a sheet of aerosol-generating substrate (25) for an aerosol-generating article.

Description

[0001] METHOD AND APPARATUS FOR PRODUCING A SHEET OF AEROSOLGENERATING SUBSTRATE FOR AN AEROSOL-GENERATING ARTICLE

[0002] The present disclosure relates to a method and to an apparatus for producing a sheet of aerosol-generating substrate for an aerosol-generating article. The present disclosure also relates to a process for manufacturing an aerosol-generating article component and to an aerosol-generating article comprising at least one aerosol-generating article component.

[0003] Aerosol-generating articles or heat-not-burn cigarettes, in which an aerosolgenerating substrate is heated rather than combusted, are known in the art. Typically, in such heated aerosol-generating articles, an aerosol is generated by the transfer of heat from a heat source to the physically separate aerosol-generating substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0004] In a typical manufacturing process, aerosol generating articles are made from a cast sheet which is obtained through a casting process from ingredients such as tobacco powder or other nicotine containing materials, water, fibers, for instance cellulose, glycerine, guar. A first step is the manufacturing of a tobacco slurry by mixing the above ingredients. The slurry is a watery mixture of insoluble matter with a water content of 70 percent - 95 percent. In a second step, the tobacco slurry is put inside a casting box to be cast by a casting knife on a moving conveyor steel belt to create a continuous tobacco cast sheet. In a third step, once the tobacco is cast on the belt, the belt moves into heaters / dryers units where temperature is controlled to progressively heat and dry the tobacco cast sheet so that at the end the water level in the tobacco cast sheet goes below 20%. At the exit of the dryer there is a cooler where the temperature of the cast sheet is reduced before winding the cast sheet into bobbins, as a fourth step. At a fifth step, the cast sheet is unwound and slit to form smaller bobbins, crimped in between crimping rollers and wrapped into the aerosolgenerating substrate of a final consumable. The known aerosol-generating substrates may also be tobacco-free herbaceous or plant-based cast sheet or a plastic fiber-based material or a biodegradable fiber-based materials.

[0005] Preparation of the aerosol-generating substrate from dough starting material having a water content significantly lower than slurry is also known. For instance, document US 2022 / 369690 A1 discloses that the mixture may be a dough having a dry weight of at least sixty percent. The dough is kneaded, extruded in the form of the sheet and dried between 60 °C and 200 °C. The dough is a paste like mixture which is further laminated to the desired thickness of the sheet.

[0006] Document US 2017 / 258126 A1 discloses a method of preparation of a slurry for the production of a homogenized tobacco material, which comprises: suspending a binder in an aerosol-former to form a suspension, creating a cellulose pulp from cellulose fibers and water, providing a tobacco powder blend and combining the suspension of binder in aerosol-former, the cellulose pulp, the tobacco powder blend and water to form a slurry. The concentrate water / cellulose pulp is stored in a buffer tank at between about 3 and about 5 percent of cellulose fibers included in the water / cellulose pulp. The concentrate water / cellulose pulp is then diluted in a dilution tank such that the cellulose fibers are less than about 1 percent of the total weight of the pulp.

[0007] Document CN110839935A discloses a method for producing reconstituted tobacco used for heating cigarettes. Fibers are ground into a fiber pulp and then the fiber pulp, a first tobacco powder, water, a binder, and a smoke generating agent are mixed to prepare a concentrated slurry with water content of 75%.

[0008] It would be desirable to have a method and an apparatus for manufacturing a sheet of aerosol-generating substrate for an aerosol-generating article, wherein the sheet of aerosol-generating substrate obtained has good mechanical properties and wherein the method allows to reduce water and energy consumption.

[0009] I would in particular desirable to improve the mechanical properties, such as the tensile strength, of sheets of aerosol-generating substrate manufactured from doughs and to reduce water and energy consumption with respect to traditional methods employing slurries.

[0010] The present disclosure relates to a method for producing a sheet of aerosolgenerating substrate for an aerosol-generating article. The method comprises: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent and 35 percent weight per weight (w / w), i.e. the pulp is semi-solid. The method further comprises: mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough or a slurry. The method may also further comprise: forming a sheet. The method may also further comprise: drying the sheet to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0011] The inventor found that, thanks to the properties of the fibers in the pulp, the sheet of aerosol-generating substrate for an aerosol-generating article produced through this method has good mechanical properties, including tensile strength and stretching to break both in longitudinal direction (machine direction) and transverse direction. The inventor found that, when subjected to weakening or crimping processes and / or when folded into consumable plugs, the sheet obtained through this method keeps its integrity and does not break, resulting in high quality consumable plugs and reduced waste material.

[0012] The inventor found that the pulp allows to have a pulping step with a very low amount of water in the recipe.

[0013] The inventor found that the method allows to reduce energy and water consumption with respect to the sheet manufactured from traditional cast slurry which consumes a lot of energy to evaporate almost 70% water to obtain a sheet with a desired moisture content of about 8%.

[0014] The inventor found that energy and water consumption reductions are maximized when the pulp is employed to make the dough.

[0015] The inventor found that the pulp thus obtained can be handled (collected, stored, transported, dosed) quickly and easily. Indeed, during handling, no water leaks out of it.

[0016] In some embodiments, the fibers concentration may be between 15 percent w / w and 20 percent w / w, optionally of 18 percent w / w.

[0017] In some embodiments, a water content of the dough is 25 percent to 40 percent on wet weight basis, optionally 27 percent to 32 percent on wet weight basis, optionally 30 percent on wet weight basis.

[0018] In other embodiments, a water content of the slurry is 70 percent to 95 percent on wet weight basis, optionally 70 percent to 90 percent on wet weight basis, optionally of 75 percent on wet weight basis.

[0019] The amount of liquid in the pulp may comprise water and / or an aerosol forming agent. In some embodiments, the amount of liquid in the pulp is water or an aerosol forming agent. In some embodiments, the amount of liquid in the pulp is water and an aerosol forming agent. In this latter case, a ratio of the water to the aerosol forming agent in the amount of liquid in the pulp is between 0.05 w / w and 20 w / w, optionally between 0.05 w / w and 1.5 w / w.

[0020] In some embodiments, mixing further comprises: adding additional water to achieve said water content of the dough or of the slurry. The final desired water content of the slurry or of the dough may thus be achieved by adding additional water to the pulp and other ingredients.

[0021] In some embodiments, the fibers are pulped with the amount of liquid until the pulp looks like a coconut flour.

[0022] A temperature of the amount of liquid in pulping may be between 18°C and 55°C, optionally 20°C. In some embodiments, pulping is carried out in a pulping mixer. Pulping may comprise: mixing the fibers and the amount of liquid in the pulping mixer. In some embodiments, pulping is continuously carried out in the pulping mixer. In other embodiments, pulping is carried out in batches in the pulping mixer. Pulping may be carried out for a pulping time between 5 min and 40 min, optionally between 20 min and 30 min.

[0023] The inventor found that continuous mixing of pulp requires smaller equipment (less footprint) than the equipment used in batch mixing. For instance, in continuous mixing, the mixing time may be 10 min.

[0024] In some embodiments, mixing to make the dough is carried out in a dough mixer. In some embodiments, mixing to make the slurry is carried out in a slurry mixer. In some embodiments, mixing to make the dough or the slurry is carried out continuously in the dough mixer or slurry mixer. In some embodiments, mixing to make the dough or the slurry is carried out in batches in the dough mixer or slurry mixer.

[0025] In some embodiments, the method comprises: dosing the pulp to the dough mixer or slurry mixer. The pulp may be gravimetrically dosed to the dough mixer or slurry mixer. In some embodiments, the pulp is continuously dosed to the dough mixer or slurry mixer. In some embodiments, the pulp is dosed in batches to the dough mixer or slurry mixer.

[0026] The inventor found that the gravimetric dosing allows to dose the ingredients in a very accurate way.

[0027] Before pulping, the fibers may be fiber shreds. Each fiber shred may have a surface dimension between 0.5 cm2and 10 cm2. In some embodiments, the fibers come in sheets or boards, for instance 80 cm x 80 cm or less. The method may comprise: shredding the sheets or boards of fibers to obtain the fiber shreds.

[0028] After pulping, a particle size of the fibers in the pulp may be between 0.3 mm and 8 mm, optionally between 0.7 mm and 5 mm.

[0029] The fibers may comprise filaments. Each filament may have a fiber length between 200 pm and 2000 pm, optionally between 450 pm and 800 pm, optionally between 600 pm and 700 pm.

[0030] The fibers may be cellulose fibers; optionally the cellulose fibers are: soft-wood fibers, hard wood fibers, jute fibers, flax fibers or tobacco fibers.

[0031] The inventor found that fibers from sheets or boards have longer filaments (high fiber lengths, average: 700 pm) and this determines a strong mechanical properties of the resulting sheets (stronger than using fibers in powder).

[0032] The inventor found that shredding the sheets or boards allows to incorporate the fibers with high fiber lengths in doughs. In some embodiments, an amount of the fibers in the dough or slurry is 0.1 percent to 20 percent on dry weight basis; optionally the amount of the fibers in the dough or slurry is 0.1 percent to 7.0 percent on dry weight basis, optionally 0.1 to 5.0 percent, optionally of 4.0 percent on dry weight basis, optionally of 3.9 percent on dry weight basis. In some embodiments, an amount of the fibers in the dough or slurry is 15 percent to 20 percent on dry weight basis, optionally of 17.5 percent on dry weight basis.

[0033] The binder may be in powder form. The aerosol forming agent may be in liquid form. The vegetable and / or alkaloid particles may be in powder form.

[0034] In some embodiments, an amount of the binder in the dough or slurry is 1.0 percent to 7.0 percent on dry weight basis, optionally 1.5 percent to 6.5 percent on dry weight basis.

[0035] In some embodiments, an amount of the vegetable and / or alkaloid particles in the recipe is 50 percent to 80 percent on dry weight basis.

[0036] The binder may be a derivative of cellulose, optionally the derivative of cellulose is methylcellulose, ethylcellulose, ethylhydroxymethyl or carboxymethylcellulose (CMC). The binder may comprise natural pectins, optionally fruit, citrus or tobacco pectins. The binder may comprise guar gums, optionally hydroxyethyl guar or hydroxypropyl guar. The binder may comprise locust bean gums, optionally hydroxyethyl and hydroxypropyl locust bean gum. The binder may comprise alginate or starches, optionally modified or derivatized starches. The binder may comprise tamarind gum or dextran or pullalon or konjac flour or xanthan gum or a mixture of the above.

[0037] The aerosol forming agent may be a polyhydric alcohol, optionally the polyhydric alcohol is triethylene glycol, 1 ,3-butanediol or glycerine or propylene glycol. The aerosol forming agent may comprise monohydric alcohols, optionally menthol. The aerosol forming agent may comprise esters of polyhydric alcohols, optionally glycerol mono-, di- or triacetate or aliphatic esters of mono-, di- or polycarboxylic acids, optionally dimethyl dodecanedioate, dimethyl tetradecanedioate or triethyl citrate.

[0038] The vegetable and / or alkaloid particles may comprise tobacco and / or nicotine and / or other botanicals. The vegetable and / or alkaloid particles may be between 50.0 percent to 80.0 percent on dry weight basis.

[0039] The botanicals may comprise cellulose fibers, like sheet fibers or powder fibers. The botanicals may comprise one or more of: clove, star anise, lavender, rosemary, peppermint, sage, camomille, apple fibre, black tea, rosehip seeds, and lemon balm. The tobacco may comprise tobacco blends. In some embodiments, the tobacco is between 50.0 percent to 80.0 percent on dry weight basis and the other botanicals are between 1.0 percent to 20.0 percent on dry weight basis. In some other embodiments, the botanicals are 50 percent to 80 percent on dry weight basis. In some embodiments, the vegetable and / or alkaloid particles and the binder are premixed and then mixed with the pulp and the aerosol forming agent to make the dough or slurry. Pre-mixing of the vegetable and / or alkaloid particles and the binder may be carried out in a powder-mixer.

[0040] In some embodiments, the binder is deposited on the vegetable and / or alkaloid particles to disperse said binder in the vegetable and / or alkaloid particles before mixing with the pulp and the aerosol forming agent to make the dough or slurry. Depositing the vegetable and / or alkaloid particles on the binder may be carried out in a powder conveyor.

[0041] In some embodiments, pre-mixing or depositing is continuously carried out in the powder mixer or powder conveyor. In some embodiments, pre-mixing or depositing is carried out in batches in the powder mixer or powder conveyor.

[0042] In some embodiments, the method comprises: dosing the pre-mixed or dispersed vegetable and / or alkaloid particles and binder to the dough mixer or slurry mixer. The premixed or dispersed vegetable and / or alkaloid particles and binder may be gravimetrically dosed to the dough mixer or slurry mixer.

[0043] In some embodiments, the pre-mixed or dispersed vegetable and / or alkaloid particles and binder is continuously dosed to the dough mixer or slurry mixer. In some embodiments, the pre-mixed or dispersed vegetable and / or alkaloid particles and binder is dosed in batches to the dough mixer or slurry mixer.

[0044] In some embodiments, a temperature of the dough or slurry during mixing is kept between 18°C and 55°C.

[0045] The present disclosure relates to an apparatus for producing a sheet of aerosolgenerating substrate for an aerosol-generating article.

[0046] The apparatus may be configured to carry out a method for producing a sheet of aerosol-generating substrate for an aerosol-generating article. The method comprises: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent and 35 percent w / w. The method further comprises: mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough or a slurry. The method may also further comprise: forming a sheet. The method may also further comprise: drying the sheet to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0047] The apparatus may comprise: a pulping mixer; a fiber source (optionally a fiber tank), and a liquid source (optionally a liquid tank), connected to the pulping mixer; a dough or slurry mixer placed downstream of the pulping mixer and connected to the pulping mixer; a vegetable and / or alkaloid particles source (optionally a vegetable and / or alkaloid particles tank), a binder source (optionally a binder tank) and an aerosol forming agent source (optionally an aerosol forming agent tank) connected to the dough or slurry mixer.

[0048] The apparatus may also comprise flattening rollers placed downstream of the dough mixer or a casting box placed downstream the slurry mixer. The apparatus may also comprise a dryer placed downstream of the flattening rollers or casting box.

[0049] The apparatus may also comprise a control unit. In some embodiments, the control unit is configured for controlling the pulping mixer, the fiber source, the liquid source, the vegetable and / or alkaloid particles source, the binder source, the aerosol forming agent source, the dough mixer or slurry mixer. The control unit may be configured for controlling the flattening rollers and the dryer.

[0050] The control unit may be configured to execute the following procedure: dosing fibers from the fiber source and an amount liquid from the liquid source to the pulping mixer according to a ratio of the fibers to the amount of liquid between 10 percent w / w and 35 percent w / w; pulping the fibers with the amount of liquid in the pulping mixer to make a pulp.

[0051] The procedure may comprise: dosing the pulp from the pulping mixer to the dough or slurry mixer. The procedure may comprise: dosing vegetable and / or alkaloid particles from the vegetable and / or alkaloid particles source to the dough or slurry mixer, dosing a binder from the binder source to the dough or slurry mixer. The procedure may comprise: dosing an aerosol forming agent from the aerosol forming agent source to the dough or slurry mixer. The procedure may comprise: mixing the pulp with vegetable and / or alkaloid particles, the binder and the aerosol forming agent to make a dough or a slurry.

[0052] In some embodiments, a water content of the dough is 25 percent to 40 percent on wet weight basis. In some embodiments a water content of the slurry is 70 percent to 95 percent on wet weight basis.

[0053] In some embodiments, the procedure comprises: feeding the dough to the flattening rollers to flatten the dough to form a sheet. In some embodiments the procedure comprises: casting the slurry through the casting box to form a sheet.

[0054] The procedure may comprise: drying the sheet in the dryer to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0055] In some embodiments, the liquid source comprises at least one of a water source and an aerosol forming agent source.

[0056] The control unit may be configured to dose water from the water source and / or aerosol forming agent from the aerosol forming agent source, the amount liquid comprising the water and / or the aerosol forming agent. In some embodiments, the apparatus comprises a main water source connected to the dough or slurry mixer. The control unit may be configured for controlling the main water source to dose additional water to achieve said water content of the dough or slurry.

[0057] In some embodiments, the pulping mixer is a continuous mixer. In some embodiments, the pulping mixer is a batch mixer. In some embodiments, the dough or slurry mixer is a continuous mixer. In some embodiments, the dough or slurry mixer is a batch mixer.

[0058] In some embodiments, the pulping mixer is a vertical mixer. In some embodiments, the pulping mixer is a horizontal mixer. In some embodiments, the dough or slurry mixer is a horizontal mixer. In some embodiments, the dough or slurry mixer is a vertical mixer.

[0059] The apparatus may comprise a pulp conveyor placed between the pulping mixer and the dough or slurry mixer. The control unit may be operatively connected to the pulp conveyor and may be configured for controlling the pulp conveyor to dose the pulp to the dough or slurry mixer.

[0060] In some embodiments, the pulp conveyor comprises a gravimetric dosing unit configured to dose gravimetrically the pulp to the dough or slurry mixer. The pulp conveyor may be a screw conveyor or a belt conveyor. The pulp conveyor may comprise a hopper configured to receive the pulp from the pulping mixer.

[0061] The apparatus may comprise a powder conveyor placed downstream of the vegetable and / or alkaloid particles source and the binder source and upstream of the dough or slurry mixer. The control unit may be operatively connected to the powder conveyor and may be configured for controlling the powder conveyor to dose the vegetable and / or alkaloid particles and the binder to the dough or slurry mixer.

[0062] The powder conveyor may be a screw conveyor or a belt conveyor. The powder conveyor may comprise a hopper configured to receive the vegetable and / or alkaloid particles and the binder from the vegetable and / or alkaloid particles source and the binder source.

[0063] The control unit may be also configured for controlling the vegetable and / or alkaloid particles source and the binder source to deposit the binder on the vegetable and / or alkaloid particles in the powder conveyor.

[0064] In some embodiments, a powder mixer is placed downstream of the vegetable and / or alkaloid particles source and the binder source and upstream of the powder conveyor. The control unit may be operatively connected to the powder mixer and may be configured for controlling the powder mixer to mix the vegetable and / or alkaloid particles and the binder. In some embodiments, a grinder is operatively placed upstream of the vegetable and / or alkaloid particles source and is configured to grind vegetables and / or alkaloids to particle size.

[0065] In some embodiments, the dough mixer or slurry mixer comprises cooling devices. The control unit may be operatively connected to the cooling devices and may be configured to control a temperature of the dough or slurry.

[0066] In some embodiments, the apparatus comprises a shredder placed upstream of the fiber source. The fibers come in sheets or boards and the shredder is configured to shred the sheets or boards to obtain fiber shreds in the fiber source, said fiber shreds being fed from the fiber source to the dough or slurry mixer.

[0067] The present disclosure also relates to a process for manufacturing an aerosolgenerating article component. The process comprises: manufacturing a sheet of aerosolgenerating substrate for an aerosol-generating article through a method for producing a sheet of aerosol-generating substrate for an aerosol-generating article. The method comprises: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent and 35 percent w / w. The method further comprises: mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough or a slurry. The method may also further comprise: forming a sheet. The method may also further comprise: drying the sheet to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0068] In some embodiments, the process comprises: gathering the sheet of aerosolgenerating substrate. In some embodiments, the process comprises: wrapping the gathered sheet of aerosol-generating substrate in a wrapper to form a continuous rod. In some embodiments, the process comprises: cutting the continuous rod into a plurality of aerosolgenerating article components each having a rod shape, each aerosol-generating article component comprising a gathered sheet formed from a cut portion of the sheet of aerosolgenerating substrate.

[0069] Before gathering, the process may also comprise: weakening the sheet of aerosolgenerating substrate by making weakened lines in said sheet of aerosol-generating substrate. In some embodiments, the weakened lines are made through a crimping step generating a plurality of substantially parallel ridges or corrugations.

[0070] The present disclosure also relates to an aerosol-generating article comprising at least one aerosol-generating article component made according to a process for manufacturing an aerosol-generating article component. The process comprises: manufacturing a sheet of aerosol-generating substrate for an aerosol-generating article through a method for producing a sheet of aerosol-generating substrate for an aerosol- generating article. The method comprises: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent and 35 percent w / w. The method further comprises: mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough or a slurry. The method may also further comprise: forming a sheet. The method may also further comprise: drying the sheet to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0071] In some embodiments, the process comprises: gathering the sheet of aerosolgenerating substrate. In some embodiments, the process comprises: wrapping the gathered sheet of aerosol-generating substrate in a wrapper to form a continuous rod. In some embodiments, the process comprises: cutting the continuous rod into a plurality of aerosolgenerating article components each having a rod shape, each aerosol-generating article component comprising a gathered sheet formed from a cut portion of the sheet of aerosolgenerating substrate.

[0072] Before gathering, the process may also comprise: weakening the sheet of aerosolgenerating substrate by making weakened lines in said sheet of aerosol-generating substrate. In some embodiments, the weakened lines are made through a crimping step generating a plurality of substantially parallel ridges or corrugations.

[0073] As used in the present description, the term “pulping” refers to the process of dispersing fibers into a liquid (like water or water / glycerine) by applying mechanical forces.

[0074] As used in the present description, the “pulp” is the resulting hydrated fibrous material with a reduced particle size due to the mechanical work of “pulping”.

[0075] As used in the present description, the term “dough” means a past like mixture that is stiff enough to be kneaded or rolled out, as opposed to a “slurry” which is a watery mixture of insoluble matter with a water content so high (e.g. 70 percent - 95 percent) that cannot be kneaded or rolled out.

[0076] As used in the present description, the terms “upstream” and “downstream” are used to describe the relative positions of components, or portions of components, of the apparatus in relation to the direction in which a material or materials passes through the apparatus along a given path.

[0077] As used in the present description, the term “recipe” means a group of ingredients without any limitation concerning the order and the timing in which they are combined with each other and / or with water.

[0078] The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein. EX1. A method for producing a sheet of aerosol-generating substrate for an aerosol-generating article, the method comprising: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent and 35 percent weight per weight (w / w); then mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough or a slurry; forming a sheet; drying the sheet to obtain a sheet of aerosol-generating substrate for an aerosolgenerating article.

[0079] EX2. The method according to EX1 , wherein the fibers concentration is between 15 percent w / w and 20 percent w / w, optionally of 18 percent w / w.

[0080] EX3. The method according to EX1 or EX2, wherein a water content of the dough is 25 percent to 40 percent on wet weight basis, optionally 27 percent to 32 percent on wet weight basis, optionally 30 percent on wet weight basis; or wherein a water content of the slurry is 70 percent to 95 percent on wet weight basis, optionally 70 percent to 90 percent on wet weight basis, optionally of 75 percent on wet weight basis.

[0081] EX4. The method according to any of EX1 to EX3, wherein the amount of liquid in the pulp comprises water and / or an aerosol forming agent.

[0082] EX5. The method according to any of EX1 to EX4, wherein the amount of liquid in the pulp is water or an aerosol forming agent.

[0083] EX6. The method according to any of EX1 to EX4, wherein the amount of liquid in the pulp is water and an aerosol forming agent.

[0084] EX7. The method according to EX6, a ratio of the water to the aerosol forming agent in the amount of liquid in the pulp is between 0.05 w / w and 20 w / w, optionally between 0.05 w / w and 1.5 w / w.

[0085] EX8. The method according to any of EX1 to EX7, wherein mixing further comprises: adding additional water to achieve said water content of the dough or of the slurry.

[0086] EX9. The method according to any of EX1 to EX8, wherein the fibers are pulped with the amount of liquid until the pulp looks like a coconut flour.

[0087] EX10. The method according to any of EX1 to EX9, wherein a temperature of the amount of liquid in pulping is between 18°C and 55°C, optionally 20°C.

[0088] EX11 . The method according to any of EX1 to EX10, wherein pulping is carried out in a pulping mixer.

[0089] EX12. The method according to EX11 , wherein pulping comprises: mixing the fibers and the amount of liquid in the pulping mixer.

[0090] EX13. The method according to EX11 or EX12, wherein pulping is continuously carried out in the pulping mixer or carried out in batches in the pulping mixer. EX14. The method according to any of EX1 to EX13, wherein pulping is carried out for a pulping time between 5 min and 40 min, optionally between 20 min and 30 min.

[0091] EX15. The method according to any of EX1 to EX14, wherein mixing to make the dough or the slurry is carried out in a dough mixer or in a slurry mixer.

[0092] EX16. The method according to EX15, wherein mixing to make the dough or the slurry is carried out continuously in the dough mixer or slurry mixer or carried out in batches in the dough mixer or slurry mixer.

[0093] EX17. The method according to EX15 or EX16, wherein the method comprises: dosing the pulp to the dough mixer or slurry mixer; optionally the pulp is gravimetrically dosed to the dough mixer or slurry mixer.

[0094] EX18. The method according to EX17, wherein the pulp is continuously dosed to the dough mixer or slurry mixer or dosed in batches to the dough mixer or slurry mixer.

[0095] EX19. The method according to any of EX1 to EX18, wherein, before pulping the fibers are fiber shreds; optionally each fiber shred has a surface dimension between 0.5 cm2and 10 cm2.

[0096] EX20. The method according to EX19, wherein the fibers come in sheets or boards (for instance 80 cm x 80 cm or less) and the method comprises: shredding the sheets or boards of fibers to obtain the fiber shreds.

[0097] EX21. The method according to any of EX1 to EX20, wherein, after pulping, a particle size of the fibers in the pulp is between 0.3 mm and 8 mm, optionally between 0.7 mm and 5 mm.

[0098] EX22. The method according to any of EX1 to EX21 , wherein the fibers comprise filaments; optionally each filament has a fiber length between 200 pm and 2000 pm, optionally between 450 pm and 800 pm, optionally between 600 pm and 700 pm.

[0099] EX23. The method according to any of EX1 to EX22, wherein the fibers are cellulose fibers; optionally the cellulose fibers are: soft-wood fibers, hard wood fibers, jute fibers, flax fibers or tobacco fibers.

[0100] EX24. The method according to any of EX1 to EX23, wherein an amount of the fibers in the dough or slurry is 0.1 percent to 20 percent on dry weight basis; optionally the amount of the fibers in the dough or slurry is 0.1 percent to 7.0 percent on dry weight basis, optionally 0.1 to 5.0 percent, optionally of 4.0 percent on dry weight basis, optionally of 3.9 percent on dry weight basis; optionally the amount of the fibers in the dough or slurry is 15 percent to 20 percent on dry weight basis, optionally of 17.5 percent on dry weight basis.

[0101] EX25. The method according to any of EX1 to EX24, wherein the binder is in powder form. EX26. The method according to any of EX1 to EX25, wherein the aerosol forming agent is in liquid form.

[0102] EX27. The method according to any of EX1 to EX26, wherein the vegetable and / or alkaloid particles are in powder form.

[0103] EX28. The method according to any of EX1 to EX27, wherein an amount of the binder in the dough or slurry is 1.0 percent to 7.0 percent on dry weight basis, optionally 1.5 percent to 6.5 percent on dry weight basis.

[0104] EX29. The method according to any of EX1 to EX28, wherein an amount of the aerosol forming agent in the dough or slurry is 10 percent to 20 percent on dry weight basis.

[0105] EX30. The method according to any of EX1 to EX29, wherein an amount of the vegetable and / or alkaloid particles in the recipe is 50 percent to 80 percent on dry weight basis.

[0106] EX31. The method according to any of EX1 to EX30, wherein the binder is a derivative of cellulose, optionally the derivative of cellulose is methylcellulose, ethylcellulose, ethylhydroxymethyl or carboxymethylcellulose (CMC); or the binder comprises natural pectins, optionally fruit, citrus or tobacco pectins; or guar gums, optionally hydroxyethyl guar or hydroxypropyl guar; or locust bean gums, optionally hydroxyethyl and hydroxypropyl locust bean gum; or alginate; or starches, optionally modified or derivitized starches; or tamarind gum; or dextran; or pullalon; or konjac flour; or xanthan gum; or a mixture of the above.

[0107] EX32. The method according to any of EX1 to EX31 , wherein the aerosol forming agent is a polyhydric alcohol, optionally the polyhydric alcohol is triethylene glycol, 1 ,3- butanediol or glycerine or propylene glycol; or the aerosol forming agent comprises monohydric alcohols, optionally menthol; or esters of polyhydric alcohols, optionally glycerol mono-, di- or triacetate; or aliphatic esters of mono- , di- or polycarboxylic acids, optionally dimethyl dodecanedioate, dimethyl tetradecanedioate or triethyl citrate.

[0108] EX33. The method according to any of EX1 to EX32, wherein the vegetable and / or alkaloid particles comprise tobacco and / or nicotine and / or other botanicals.

[0109] EX34. The method according to EX33, wherein the botanicals are between 50.0 percent to 80.0 percent on dry weight basis.

[0110] EX35. The method according to EX33 or EX34, wherein the botanicals comprise cellulose fibers, like sheet fibers or powder fibers optionally the botanicals comprise one or more of: clove, star anise, lavender, rosemary, peppermint, sage, camomille, apple fibre, black tea, rosehip seeds, and lemon balm.

[0111] EX36. The method according to EX33 or EX34, wherein the pulp is mixed also with hydroxypropylmethil cellulose. EX37. The method according to any of EX33 to EX36, wherein the tobacco is between 50.0 percent to 80.0 percent on dry weight basis and the other botanicals are between 1 .0 percent to 20.0 percent on dry weight basis.

[0112] EX38. The method according to any of EX1 to EX37, wherein the vegetable and / or alkaloid particles and the binder are pre-mixed and then mixed with the pulp and the aerosol forming agent to make the dough or slurry.

[0113] EX39. The method according to EX38, wherein pre-mixing of the vegetable and / or alkaloid particles and the binder is carried out in a powder-mixer.

[0114] EX40. The method according to any of EX1 to EX39, wherein the binder is deposited on the vegetable and / or alkaloid particles to disperse said binder in the vegetable and / or alkaloid particles before mixing with the pulp and the aerosol forming agent to make the dough or slurry.

[0115] EX41. The method according to EX40, wherein depositing the vegetable and / or alkaloid particles on the binder is carried out in a powder conveyor.

[0116] EX42. The method according to EX39 or EX41 , wherein pre-mixing or depositing is continuously carried out in the powder mixer or powder conveyor or carried out in batches in the powder mixer or powder conveyor.

[0117] EX43. The method according to any of EX33 to EX42, wherein the method comprises: dosing the pre-mixed or dispersed vegetable and / or alkaloid particles and binder to the dough mixer or slurry mixer; optionally the pre-mixed or dispersed vegetable and / or alkaloid particles and binder is gravimetrically dosed to the dough mixer or slurry mixer.

[0118] EX44. The method according to EX43, wherein the pre-mixed or dispersed vegetable and / or alkaloid particles and binder is continuously dosed to the dough mixer or slurry mixer or dosed in batches to the dough mixer or slurry mixer.

[0119] EX45. The method according to any of EX1 to EX44, wherein a temperature of the dough or slurry during mixing is kept between 18°C and 55°C.

[0120] EX46. An apparatus for producing a sheet of aerosol-generating substrate for an aerosol-generating article, the apparatus comprising: a pulping mixer; a fiber source (optionally a fiber tank), and a liquid source (optionally a liquid tank), connected to the pulping mixer; a dough or slurry mixer placed downstream of the pulping mixer and connected to the pulping mixer; a vegetable and / or alkaloid particles source (optionally a vegetable and / or alkaloid particles tank), a binder source (optionally a binder tank) and an aerosol forming agent source (optionally an aerosol forming agent tank) connected to the dough or slurry mixer; flattening rollers placed downstream of the dough mixer or a casting box placed downstream the slurry mixer; a dryer placed downstream of the flattening rollers or casting box; a control unit.

[0121] EX47. The apparatus according to EX46, wherein said apparatus is configured to carry out the method according to any of EX1 to EX45.

[0122] EX48. The apparatus according to EX46 or EX47, wherein the control unit is configured for controlling the pulping mixer, the fiber source, the liquid source, the vegetable and / or alkaloid particles source, the binder source, the aerosol forming agent source, the dough mixer or slurry mixer, optionally the flattening rollers and the dryer.

[0123] EX49. The apparatus according to any of EX46 to EX48, wherein the control unit is configured to execute the following procedure: dosing fibers from the fiber source and an amount liquid from the liquid source to the pulping mixer according to a ratio of the fibers to the amount of liquid between 10 percent w / w and 35 percent w / w; pulping the fibers with the amount of liquid in the pulping mixer to make a pulp; dosing the pulp from the pulping mixer to the dough or slurry mixer; dosing vegetable and / or alkaloid particles from the vegetable and / or alkaloid particles source to the dough or slurry mixer, dosing a binder from the binder source to the dough or slurry mixer; dosing an aerosol forming agent from the aerosol forming agent source to the dough or slurry mixer; mixing the pulp with vegetable and / or alkaloid particles, the binder and the aerosol forming agent to make a dough or a slurry, wherein a water content of the dough is 25 percent to 40 percent on wet weight basis or wherein a water content of the slurry is 70 percent to 95 percent on wet weight basis;

[0124] - feeding the dough to the flattening rollers to flatten the dough or casting the slurry through the casting box to form a sheet; drying the sheet in the dryer to obtain a sheet of aerosol-generating substrate for an aerosol-generating article.

[0125] EX50. The apparatus according to any of EX46 to EX49, wherein the liquid source comprises at least one of a water source and an aerosol forming agent source.

[0126] EX51 . The apparatus according to EX50, wherein the control unit is configured to dose water from the water source and / or aerosol forming agent from the aerosol forming agent source, the amount liquid comprising the water and / or the aerosol forming agent. EX52. The apparatus according to any of EX46 to EX51 , further comprising a main water source connected to the dough or slurry mixer, wherein the control unit is configured for controlling the main water source to dose additional water to achieve said water content of the dough or slurry.

[0127] EX53. The apparatus according to any of EX46 to EX52, wherein the pulping mixer is a continuous mixer or a batch mixer and / or the dough or slurry mixer is a continuous mixer or a batch mixer.

[0128] EX54. The apparatus according to any of EX46 to EX53, wherein the pulping mixer is a vertical mixer or a horizontal mixer and / or the dough or slurry mixer is a vertical mixer or a horizontal mixer.

[0129] EX55. The apparatus according to any of EX46 to EX54, comprising a pulp conveyor placed between the pulping mixer and the dough or slurry mixer wherein the control unit is operatively connected to the pulp conveyor and is configured for controlling the pulp conveyor to dose the pulp to the dough or slurry mixer.

[0130] EX56. The apparatus according to EX55, wherein the pulp conveyor comprises a gravimetric dosing unit configured to dose gravimetrically the pulp to the dough or slurry mixer.

[0131] EX57. The apparatus according to EX55 or EX56, wherein the pulp conveyor is a screw conveyor or a belt conveyor; optionally the pulp conveyor comprising a hopper configured to receive the pulp from the pulping mixer.

[0132] EX58. The apparatus according to any of EX46 to EX57, comprising a powder conveyor placed downstream of the vegetable and / or alkaloid particles source and the binder source and upstream of the dough or slurry mixer, wherein the control unit is operatively connected to the powder conveyor and is configured for controlling the powder conveyor to dose the vegetable and / or alkaloid particles and the binder to the dough or slurry mixer.

[0133] EX59. The apparatus according to EX58, wherein the control unit is configured for controlling the vegetable and / or alkaloid particles source and the binder source to deposit the binder on the vegetable and / or alkaloid particles in the powder conveyor.

[0134] EX60. The apparatus according to EX58 or EX59, wherein the powder conveyor is a screw conveyor or a belt conveyor; optionally the powder conveyor comprising a hopper configured to receive the vegetable and / or alkaloid particles and the binder from the vegetable and / or alkaloid particles source and the binder source.

[0135] EX61. The apparatus according to any of EX58 to EX60, comprising a powder mixer placed downstream of the vegetable and / or alkaloid particles source and the binder source and upstream of the powder conveyor, wherein the control unit is operatively connected to the powder mixer and is configured for controlling the powder mixer to mix the vegetable and / or alkaloid particles and the binder.

[0136] EX62. The apparatus according to any of EX46 to EX61 , comprising a grinder operatively placed upstream of the vegetable and / or alkaloid particles source and configured to grind vegetables and / or alkaloids to particle size.

[0137] EX63. The apparatus according to any of EX46 to EX57, wherein the dough mixer or slurry mixer comprises cooling devices, the control unit being operatively connected to the cooling devices and being configured to control a temperature of the dough or slurry.

[0138] EX64. The apparatus according to any of EX46 to EX63, comprising a shredder placed upstream of the fiber source, wherein the fibers come in sheets or boards and the shredder is configured to shred the sheets or boards to obtain fiber shreds in the fiber source, said fiber shreds being fed from the fiber source to the dough or slurry mixer.

[0139] EX65. A process for manufacturing an aerosol-generating article component, comprising: manufacturing a sheet of aerosol-generating substrate for an aerosol-generating article through the method according to any of EX1 to EX39 or in the apparatus according to any of EX46 to EX64; gathering the sheet of aerosol-generating substrate and wrapping the gathered sheet of aerosol-generating substrate in a wrapper to form a continuous rod; cutting the continuous rod into a plurality of aerosol-generating article components each having a rod shape, each aerosol-generating article component comprising a gathered sheet formed from a cut portion of the sheet of aerosol-generating substrate.

[0140] EX66. The process according to EX65, wherein, before gathering, the process comprises: weakening the sheet of aerosol-generating substrate by making weakened lines in said sheet of aerosol-generating substrate, optionally through a crimping step generating a plurality of substantially parallel ridges or corrugations.

[0141] EX67. An aerosol-generating article comprising at least one aerosol-generating article component made according to the process of EX65 or EX66.

[0142] Examples will now be further described with reference to the figures in which:

[0143] Figure 1 shows schematically an apparatus for producing a sheet of aerosolgenerating substrate for an aerosol-generating article according to the invention;

[0144] Figures 2 shows schematically an embodiment variant of the apparatus of figure 1 ;

[0145] Figure 3 shows in greater detail a portion of the apparatus of figure 1 or 2;

[0146] Figure 4 shows in greater detail a variant of the portion of figure 3; Figure 5 shows schematically an apparatus for making a continuous rod from the sheet of aerosol-generating substrate manufactured in the apparatus of figures 1 to 4;

[0147] Figures 6 and 7 shows respectively an axial section and a cross section of an aerosolgenerating article component made through the apparatuses of figures 1 to 5;

[0148] Figure 8 is a flowchart of a method for producing a sheet of aerosol-generating substrate for an aerosol-generating article according to embodiments of the invention.

[0149] The apparatus 1 shown in Figure 1 is a schematic example of an apparatus configured for carrying out a method for producing a sheet of aerosol-generating substrate for an aerosol-generating article according to the invention.

[0150] The apparatus 1 comprises a vegetable and / or alkaloid particles source 2, for instance a tank containing tobacco powder, a binder source 3, for instance a tank containing carboxymethylcellulose (CMC) powder, an aerosol forming agent source 4, for instance a tank containing liquid glycerine, a source or tank of water 5, a fiber source 6, i.e. a tank containing cellulose fibers, a main water source 7, for instance a tank of additional water, another aerosol forming agent source 8, for instance another tank containing liquid glycerine. The tobacco may comprise tobacco blends.

[0151] A grinder, not shown, may be operatively placed upstream of the vegetable and / or alkaloid particles source 2 to grind the vegetables and / or alkaloids to a required particle size.

[0152] In other embodiments, the vegetable and / or alkaloid particles comprise tobacco and other botanicals. The tobacco may be between 50.0 percent to 80.0 percent on dry weight basis and the other botanicals may be between 1.0 percent to 20.0 percent on dry weight basis. In other embodiments, the vegetable and / or alkaloid particles comprise botanicals instead of tobacco and the botanicals are 50 percent to 80 percent on dry weight basis. For instance, the botanicals comprise cellulose fibers, like sheet fibers or powder fibers. The botanicals may comprise clove, star anise, lavender, rosemary, peppermint, sage, camomille, apple fibre, black tea, rosehip seeds, and lemon balm.

[0153] In other embodiments, the binder is methylcellulose, ethylcellulose or ethylhydroxymethyl. In other embodiments, the binder comprises natural pectins, like fruit, citrus or tobacco pectins. In other embodiments, the binder comprises guar gums, like hydroxyethyl guar or hydroxypropyl guar. In other embodiments, the binder comprises locust bean gums, like hydroxyethyl and hydroxypropyl locust bean gum. In other embodiments, the binder comprises alginate or starches, like modified or derivitized starches. In other embodiments, the binder comprises tamarind gum or dextran or pullalon or konjac flour or xanthan gum. In other embodiments, the binder comprises a mixture of the above. In other embodiments, the aerosol forming agent is triethylene glycol, 1 ,3-butanediol or propylene glycol. In other embodiments, the aerosol forming agent comprises monohydric alcohols, like menthol. In other embodiments, the aerosol forming agent comprises esters of polyhydric alcohols, like glycerol mono-, di- or triacetate or aliphatic esters of mono-, di- or polycarboxylic acids, like dimethyl dodecanedioate, dimethyl tetradecanedioate or triethyl citrate.

[0154] For instance, the cellulose fibers are: soft-wood fibers, hard wood fibers, jute fibers, flax fibers or tobacco fibers. The filaments of fibers have a fiber length between 200 pm and 2000 pm, for instance between 450 pm and 800 pm, for instance between 600 pm and 700 pm.

[0155] In preferred embodiments, the apparatus 1 may is provided with a shredder 100, shown schematically in figures 1 and 2, operatively working upstream of the tank containing the cellulose fibers. The fibers are fed to the shredder 100 in sheets or boards (for instance 80 cm x 80 cm) and the shredder 100 shreds the sheets or boards to obtain fiber shreds, each having a surface dimension between 0.5 cm2and 10 cm2.

[0156] The apparatus 1 comprises a powder mixer 9 placed downstream of the vegetable and / or alkaloid particles tank 2 and of the binder tank 3. The vegetable and / or alkaloid particles tank 2 and the binder tank 3 are connected to the powder mixer 9, for instance through pipes, valves and pumps, to allow feeding this latter with the tobacco powder and the carboxymethylcellulose (CMC) powder. The powder mixer 9 is structured and configured to mix the tobacco powder and the carboxymethylcellulose (CMC) powder. Therefore, the vegetable and / or alkaloid particles (tobacco) and the binder (CMC) are premixed in the powder mixer 9.

[0157] The apparatus 1 comprises a powder conveyor 10 placed downstream of the powder mixer 9. The powder conveyor 10 is represented as a screw conveyor having an inlet provided with a hopper 11 configured to receive the tobacco powder and the carboxymethylcellulose (CMC) powder from the powder conveyor 10. The screw conveyor has an outlet 12 from which the mixed tobacco and carboxymethylcellulose (CMC) powders are discharged.

[0158] The apparatus 1 further comprises a pulping mixer 13 placed downstream of the aerosol forming agent tank 4, the tank of water 5 and the fiber tank 6. The aerosol forming agent tank 4, the tank of water 5 and the fiber tank 6 are connected to the pulping mixer 13, for instance through pipes, valves and pumps, to allow feeding this latter with the lignocellulosic fibers, the water and the glycerine. The pulping mixer 13 may be a vertical mixer or a horizontal mixer and is structured and configured to disperse fibers into a liquid (like water or water / glycerine) by applying mechanical forces. The apparatus 1 comprises a pulp conveyor 14 placed downstream of the pulping mixer 13. The pulp conveyor 14 is represented as a screw conveyor having an inlet provided with a hopper 15 configured to receive the pulp from the pulping mixer 13. The screw conveyor has an outlet 16 from which the pulp is discharged. The pulp conveyor 14 may also be a belt conveyor.

[0159] The apparatus 1 further comprises a dough mixer 17 placed downstream of the powder conveyor 10 and of the pulp conveyor 14 in order to receive the mixed tobacco and carboxymethylcellulose (CMC) powders from the outlet 12 of the powder conveyor 10 and to receive the pulp from the outlet 16 of the pulp conveyor 14.

[0160] The dough mixer 17 is also connected to the main water source 7 and to the another aerosol forming agent tank 8, for instance through pipes, valves and pumps, to receive the additional water from the main water source 7 and additional glycerine from the another aerosol forming agent tank 8.

[0161] The apparatus 1 comprises a control unit 18, represented schematically in figure 1 , operatively connected to the vegetable and / or alkaloid particles source 2, the binder source 3, the aerosol forming agent source 4, the source of water 5, the fiber source 6, the main water source 7, the aerosol forming agent source 8, the powder mixer 9, the powder conveyor 10, the pulping mixer 13, the pulp conveyor 14 and the dough mixer 17. The control unit 18 is connected, for instance, to motors and / or valves and / or pumps part of the above cited devices or of pipes connecting the above cited devices. The control unit 18 is for instance an electronic control unit comprising a CPU, storage memories, input and output devices. The control unit 18 is configured to store and run a software program and to execute a control procedure to manage the cited devices of the apparatus 1 in order to carry out the method for producing a sheet of aerosol-generating substrate for an aerosolgenerating article of the invention.

[0162] The control unit 18 is configured to dose an amount of the tobacco powder and an amount of the carboxymethylcellulose (CMC) powder in the powder mixer 9 according to a predefined recipe and to control the powder mixer 9 and the powder conveyor 10 to dose the pre-mixed powders in the dough mixer 17. In other embodiments, the binder (e.g. CMC) is deposited on the vegetable and / or alkaloid particles (e.g. tobacco) to disperse said binder in the vegetable and / or alkaloid particles before feeding to the dough mixer 17. Depositing the vegetable and / or alkaloid particles on the binder may be carried out in the powder conveyor 10.

[0163] The pre-mixed or dispersed vegetable and / or alkaloid particles and binder are gravimetrically dosed to the dough mixer 17. Therefore, the powder conveyor 10 comprises a gravimetric dosing unit, not shown in drawings, controlled by the control unit 18 and configured to dose gravimetrically the pre-mixed powders to the dough mixer 17.

[0164] Mixing in the powder mixer 9 and conveying in the powder conveyor 10 are carried out in batches. Otherwise, powder mixing and conveying are continuously carried out in the powder mixer 9 and powder conveyor 10.

[0165] The control unit 18 is configured to dose an amount of the glycerine from the aerosol forming agent source 4, an amount of water from the water source 5 and an amount of fibers from the fiber source 6 in the pulping mixer 13 according to the predefined recipe and in order to make a pulp having a fibers concentration between 10 percent and 35 percent w / w (mass percentage weight per weight), i.e. the pulp is semi-solid. An amount of liquid in the pulp comprises water and glycerine. For instance, a ratio of the water to the glycerine in the amount of liquid in the pulp is between 0.05 w / w and 20 w / w, for instance between 0.05 w / w and 1 .5 w / w. For instance, the fibers concentration is between 15 percent and 20 percent w / w, for instance of 18 percent w / w.

[0166] The control unit 18 controls the pulping mixer 13 to pulp the fibers with the amount of water and the amount of glycerine to make the pulp and controls the pulp conveyor 14 to dose the pulp to the dough mixer 17. After pulping, a particle size of the fibers in the pulp is between 0.3 mm and 8 mm, optionally between 0.7 mm and 5 mm.

[0167] The pulp from the pulping mixer 13 looks like a coconut flour and may be dosed gravimetrically to the dough mixer 17. Therefore, the pulp conveyor 14 comprises a gravimetric dosing unit, not shown in drawings, controlled by the control unit 18 and configured to dose gravimetrically the pulp to the dough mixer 17. A temperature of water and / or glycerine fed to the pulping mixer 13 may also be controlled, by the control unit 18 and through heaters and / or coolers, to be between 18°C and 55°C, for instance of 20°C.

[0168] Pulping in the pulping mixer 13 is carried out in batches (batch mixer) for a pulping time between 5 min and 40 min, for instance between 20 min and 30 min, and the resulting pulp is dosed in batches to the dough mixer 17. Otherwise, pulping is continuously carried out in the pulping mixer 13 (continuous mixer) for a mixing time, for instance, of 10 min and the resulting pulp is dosed continuously to the dough mixer 17. For instance, a mixing speed in the pulping mixer 13 is 180 RPM.

[0169] The control unit 18 is configured for controlling the main water source 7 to dose additional water to achieve a predefined water content of a dough “D” in the dough mixer 17 and for controlling the aerosol forming agent source 8 to dose additional glycerine to achieve a predefined glycerine content of the dough “D” in the dough mixer 17.

[0170] The dough mixer 17 may be horizontal mixer or a vertical mixer and comprises kneading elements 19, one represented schematically in figure 3, which are configured for mixing the pulp, the pre-mixed tobacco and carboxymethylcellulose (CMC) powders, water and glycerine to make the dough “D”, i.e. a paste like mixture having a water content between 25 percent and 40 percent on wet weight basis. For instance, the water content of the dough “D” is between 27 percent and 32 percent on wet weight basis, for instance 30 percent on wet weight basis. The kneading elements 19 may be, for instance, counter rotating screws.

[0171] Mixing to make the dough “D” is carried out in batches in the dough mixer 17 (batch mixer). Otherwise, mixing to make the dough “D” is carried out continuously in the dough 17 (continuous mixer).

[0172] A temperature of the dough “D” during mixing may be controlled through cooling devices in order to keep said temperature between 18°C and 55°C.

[0173] An amount of the fibers in the final dough “D” may be between 0.1 percent to 20 percent on dry weight basis, for instance 0.1 percent to 5.0 percent on dry weight basis. In some embodiments, the amount of the fibers in the final dough “D” is 3.9 or 4.0 percent on dry weight basis. In some other embodiments, said amount of the fibers in the dough “D” is 15 percent to 20 percent on dry weight basis, for instance of 17.5 percent on dry weight basis. An amount of the binder (e.g. CMC) in the dough is 1.0 percent to 7.0 percent on dry weight basis, for instance 1.5 percent to 6.5 percent on dry weight basis. An amount of the vegetable and / or alkaloid particles in the recipe is 50 percent to 80 percent on dry weight basis.

[0174] The dough “D” is then calendered through a dough-sheeter or calendaring rollers 20, which may be part of the dough mixer 17, to shape the dough “D” like a thick sheet 21. For instance, a thickness of the thick sheet 21 is between 2 mm and 20 mm.

[0175] Downstream of the dough mixer 17, the apparatus 1 comprises flattening rollers 22 which are configured to flatten the thick sheet 21 to form a flattened thin sheet 23. The non- limitative embodiment of Figure 3 shows two pairs of flattening rollers 22 arranged one after the other. A thickness of the thin sheet 23 may be between 0.15 mm and 0.35 mm, optionally between 0.15 mm and 0.30 mm, for instance between 0.172 mm and 0.285 mm.

[0176] A dryer 24 is operatively placed downstream of the flattening rollers 22 and is configured to dry the flattened thin sheet 23 and obtaining the sheet 25 of aerosolgenerating substrate for an aerosol-generating article. The dryer 24 may comprise a casing delimiting a chamber 26 and a belt conveyor 27, for instance a mesh belt, moving through the chamber 26 while supporting the thin sheet 23. Heating devices, not shown, are configured to heat and dry the thin sheet 23 moving through the chamber 26. The heating / drying technology may be a combination of infrared and hot air, microwave and hot air or via conduction through a steam-heated belt and convection with hot air. The flattened sheet 23 is dried down to a water content of 5.8 - 11.2 percent on wet weight basis, for instance to 8.5 percent on wet weight basis.

[0177] Downstream of the dryer 24, longitudinal edges of the sheet 25 are trimmed though a trimming device 28. A winder operatively placed downstream of the dryer 24 and of the trimming device 28 is configured to wind the sheet 25 of aerosol-generating substrate on a core 29 to form a master bobbin 30.

[0178] A cooling station, not shown, may be placed between the dryer 11 and the winder so that the sheet 12 of aerosol-generating substrate is cooled prior to be winded.

[0179] The control unit 18 is configured for controlling the flattening rollers 22 and the dryer 24 the trimmer 28 and the winder.

[0180] In a different embodiment, not shown in the drawings, the apparatus 1 comprise an inline slitter operatively placed downstream of the dryer 24 and configured to divide the sheet of aerosol-generating substrate 25 in a plurality of sheets 33 of reduced width. A plurality of small winders are employed for winding each sheet 33 on a respective small bobbin.

[0181] The sheet 25 of aerosol-generating substrate of the master bobbin 30 is employed in the manufacturing of aerosol-generating article components 31 and of an aerosolgenerating article. The master bobbin 30 is slit in a plurality of small bobbins 32 so that each small bobbin 32 comprises a sheet 33 of aerosol-generating substrate of reduced width which is winded on a respective portion of the core 29. Alternatively, the master bobbin is not formed and the sheet 25 of aerosol-generating substrate is longitudinally inline divided in a plurality of sheets 33 of reduced width by an inline slitter and then each sheet 33 of reduced width is wound on a respective small bobbin 32.

[0182] Each sheet 33 of reduced width of aerosol-generating substrate may be, for instance, gathered and wrapped to form a respective continuous rod 35 through an apparatus 36 for manufacturing aerosol-generating article components, a part of which is shown in Figure 5.

[0183] The apparatus 36 for manufacturing aerosol-generating article components comprises a reel holder 34 carrying the small bobbin 32 formed by the sheet 33 of reduced width of aerosol-generating substrate for an aerosol-generating article component. The sheet 33 of reduced width of aerosol-generating substrate, previously manufactured, is unwound from the small bobbin 32 and fed along a feeding path in a feeding direction “F”.

[0184] Downstream of the reel holder 34, the apparatus 1 comprises two rotating cylindrical rollers 37 between which the sheet 33 is pressed. The rollers 37 are configured to weaken the sheet 33 by making weakened lines in said sheet 33. These rollers 37 have matching textured ridge-and-trough patterns on their outside surfaces that crimp the sheet 33 through transversal stretching of substrate’s fibers. This crimping process is helpful for folding and gathering the sheet 33 of aerosol-generating substrate into rod pieces that will fit into the aerosol generating articles. Indeed, the term “crimped sheet” denotes a sheet 33 having a plurality of substantially parallel ridges or corrugations which are substantially parallel to the cylindrical axis of the rod piece. This facilitates folding and gathering of the crimped sheet 33 of aerosol-generating substrate to form the aerosol-generating article component.

[0185] Figure 5 shows schematically a folding device 25 placed downstream of the two rotating cylindrical rollers 24 and configured to move the sheet 33 from a flat configuration (upstream of the folding device 38) to a gathered rod-shaped configuration (downstream of the folding device 38) and to wrap a wrapper 39, unwound from a respective bobbin 40, around the gathered sheet 33 to obtain the continuous rod 35. The folding device 38 may be shaped like a tapered funnel. The continuous rod 35 is then cut in a plurality of aerosolgenerating article components 31.

[0186] Each aerosol-generating article component 31 has a rod shape and comprises a gathered sheet formed from a cut portion of the sheet 33 of aerosol-generating substrate wrapped in a portion of the wrapper 39 (Figures 6 and 7). The aerosol-generating article components 31 are then joined to further elements (e.g. filters or others) to manufacture the final aerosol-generating articles.

[0187] In a different embodiment, the apparatus 1 is configured to make a slurry “S” instead of a dough “D”. The slurry “S” is a watery mixture of insoluble matter with a water content so high (e.g. 70 percent - 95 percent) that cannot be kneaded or rolled out. A water content of the slurry “D” is for instance 70 percent to 90 percent on wet weight basis, for instance of 75 percent on wet weight basis.

[0188] Figure 4 shows a slurry mixer 17’ instead of the dough mixer 17 disclosed above. The slurry mixer 17’ is structured and configured to mix the watery slurry “S” in place of the dough “D”.

[0189] The slurry mixer 17’ comprises an outlet 41 located above a casting box 42. The casting box 42 is in fluid communication with the outlet 41 to receive the slurry mixture from the slurry mixer 17’ and a belt conveyor 43 is located under the casting box 42. The belt conveyor 43 comprises a first drum 44, a second drum, not shown, and a belt 45 forming a closed loop around the first drum 44 and the second drum. A conveyor motor, not shown, is connected to the first drum 44 to move an upper branch of the belt 45 along a conveying direction.

[0190] The casting box 42 has a top opening 46 and a bottom opening 47. The bottom opening 47 is close to and faces a portion of the upper branch of the belt 45 located at the first drum 44. The casting box 42 comprises a casting blade 48 delimiting a slot together with the upper branch of the belt 45. The casting blade 48 is an element having one edge that is intended to come into contact with the slurry. Said edge may have a sharp and knife-like shape or a rectangular or a rounded shape. The belt 45 is a movable support and the upper branch of the belt 45 is a movable surface located under the casting box 42 moving along the conveying direction and configured to receive the slurry from said casting box 42 and to form a cast sheet 49. The cast sheet 49 is then dried, for instance in an oven similar to the dryer 24 disclosed in figure 3, to obtain the sheet 25 of aerosol-generating substrate which may be winded on the core 29 to form the master bobbin 30, as disclosed in figure 3.

[0191] In the variant embodiment of figure 2, the powder mixer 9 and the powder conveyor 10 are not provided. The vegetable and / or alkaloid particles tank 2 and the binder tank 3 are connected to the dough mixer 17. Furthermore, differently from the embodiment of figure 1 , no aerosol forming agent source 4 is connected to the pulping mixer 13 and pulping in the pulping mixer 13 is carried out with water and cellulose fibers only (no glycerine). The other devices of the apparatus 1 are the same as the apparatus of figure 1. The dough mixer 17 of figure 2 may also be a slurry mixer 17’ as detailed above. In other embodiments, not detailed in this description, pulping is carried out only with the aerosol binder (e.g. glycerine).

[0192] Example 1 (apparatus of figure 1)

[0193] The following Table 1 contains a recipe example.

[0194] Table 1

[0195] Method steps of Example 1 are listed in Table 2.

[0196] Table 2

[0197] Dough mixer operating parameters are listed in Table 3.

[0198] Table 3

[0199] Example 2 (apparatus of figure 2)

[0200] The recipe is the same as Example 1 and also the dough mixer operations parameters. Differently from Example 1, in step 3 only water is mixed with fibers in the pulping mixer 13 (glycerine is not pre-mixed with pulp in step 3).

[0201] In both examples, the dough was visually in line with the expectation and with the reference coming from standard batch preparation. No CMC or fibers agglomeration were present. Table 4 shows the mechanical properties of sheets manufactured using the dough of Examples 1 and 2 above.

[0202] Table 4 | Strain Cross Direction | 0.05 |

[0203] The mechanical properties of the sheets manufactured through the invention are close to the mechanical properties of sheet manufactured through standard cast leaf methods. However, the invention allows to reduce water and energy consumption. Furthermore, the invention allows to treat the pulp as a solid and that is convenient because it can be dosed as a solid.

[0204] Further examples of recipes employing tobacco or other materials instead of tobacco, such as botanicals, or tobacco mixed with botanicals are exemplified in the following Table 5.

[0205] Table 5

Claims

CLAIMS1. Method for producing a sheet of aerosol-generating substrate for an aerosolgenerating article, the method comprising: pulping fibers with an amount of liquid to make a pulp, wherein a fibers concentration in the pulp is between 10 percent weight per weight and 35 percent weight per weight; then mixing the pulp with vegetable and / or alkaloid particles, a binder and an aerosol forming agent to make a dough (D) or a slurry (S); forming a sheet from the dough or slurry; drying the sheet to obtain a sheet of aerosol-generating substrate (25) for an aerosol-generating article.

2. Method according to claim 1 , wherein the fibers concentration is between 15 percent weight per weight and 20 percent weight per weight.

3. Method according to claim 1 or 2, wherein a water content of the dough (D) is 25 percent to 40 percent on wet weight basis or a water content of the slurry (S) is 70 percent to 95 percent on wet weight basis.

4. Method according to any of claims 1 to 3, wherein the amount of liquid in the pulp comprises water and / or an aerosol forming agent.

5. Method according to claim 4, wherein a ratio of the water to the aerosol forming agent in the amount of liquid in the pulp is between 0.05 weight per weight and 20 weight per weight.

6. Method according to any of claims 1 to 5, wherein mixing further comprises: adding additional water to achieve said water content of the dough (D) or of the slurry (S).

7. Method according to any of claims 1 to 6, wherein before pulping the fibers are fiber shreds; wherein the fibers come in sheets or boards and the method comprises: shredding the sheets or boards of fibers to obtain the fiber shreds.

8. Method according to any of claims 1 to 7, wherein a temperature of the amount of liquid in pulping is between 18°C and 55°C.

9. Method according to any of claims 1 to 8, wherein pulping is carried out in a pulping mixer (13); wherein mixing to make the dough (D) or the slurry (S) is carried out in a dough mixer (17) or slurry mixer (17’); wherein the method comprises: dosing gravimetrically the pulp to the dough mixer or slurry mixer.

10. Method according to claim 9, wherein pulping is continuously carried out in the pulping mixer (13) and the pulp is dosed gravimetrically to the dough or slurry mixer (17, 17’).

11. Apparatus for producing a sheet of aerosol-generating substrate for an aerosolgenerating article, the apparatus comprising: a pulping mixer (13); a fiber source (6) and a liquid source (4, 5) connected to the pulping mixer (13); a dough or slurry mixer (17, 17’) placed downstream of the pulping mixer (13) and connected to the pulping mixer (13); a vegetable and / or alkaloid particles source (2), a binder source (3) and an aerosol forming agent source (8) connected to the dough or slurry mixer (17, 17’); flattening rollers (22) placed downstream of the dough mixer (17) or a casting box (42) placed downstream the slurry mixer (17’); a dryer (24) placed downstream of the flattening rollers (22) or casting box (42); a control unit (18); wherein the control unit (18) is configured for controlling the pulping mixer (13), the fiber source (6), the liquid source (4, 5), the vegetable and / or alkaloid particles source (2), the binder source (3), the aerosol forming agent source (8), the dough mixer (17) or slurry mixer (17’), the flattening rollers (22) or casting box (42) and the dryer (24) to execute the following procedure: dosing fibers from the fiber source (6) and an amount liquid from the liquid source (4, 5) to the pulping mixer (13) according to a fibers concentration between 10 percent weight per weight and 35 percent weight per weight; pulping the fibers with the amount of liquid in the pulping mixer (13) to make a pulp; dosing the pulp from the pulping mixer (13) to the dough or slurry mixer (17, 17’); dosing vegetable and / or alkaloid particles from the vegetable and / or alkaloid particles source (2) to the dough or slurry mixer (17, 17’), dosing a binder from the binder source (3) to the dough or slurry mixer (17, 17’);dosing an aerosol forming agent from the aerosol forming agent source (8) to the dough or slurry mixer (17, 17’); mixing the pulp with vegetable and / or alkaloid particles, the binder and the aerosol forming agent to make a dough (D) or a slurry (S), wherein a water content of the dough (D) is 25 percent to 40 percent on wet weight basis or wherein a water content of the slurry (S) is 70 percent to 95 percent on wet weight basis;- feeding the dough (D) to the flattening rollers (22) to flatten the dough (D) or casting the slurry (S) through the casting box (42) to form a sheet (23, 49); drying the sheet in the dryer (24) to obtain a sheet (25) of aerosol-generating substrate for an aerosol-generating article.

12. Apparatus according to claim 11 , wherein the liquid source (4, 5) comprises at least one of a water source (5) and an aerosol forming agent source (4) and wherein the control unit (18) is configured to dose water from the water source (5) and / or aerosol forming agent from the aerosol forming agent source (4), the amount liquid comprising the water and / or the aerosol forming agent.

13. Apparatus according to claim 11 or 12, comprising a shredder (100) placed upstream of the fiber source (6), wherein the fibers come in sheets or boards and the shredder (100) is configured to shred the sheets or boards to obtain fiber shreds in the fiber source (6), said fiber shreds being fed from the fiber source (6) to the dough or slurry mixer (17, 17’).

14. Apparatus according to any of claims 11 to 13, comprising a pulp conveyor (14) placed between the pulping mixer (13) and the dough or slurry mixer (17, 17’), wherein the control unit (18) is operatively connected to the pulp conveyor (14) and is configured for controlling the pulp conveyor (14) to dose the pulp to the dough or slurry mixer (17, 17’).

15. Apparatus according to claim 14, wherein the pulp conveyor (14) comprises a gravimetric dosing unit configured to dose gravimetrically the pulp to the dough or slurry mixer (17, 17’).

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