Method of Manufacture

Technical field of the invention The present invention relates to the field of tobacco such as cigarette and its method of manufacture, in particular relates to a 3-Dimensional forming of aerosol-generating substrates comprising tobacco.

Background of the invention Conventional smoking tobacco products such as cigarette, cigarillo, cigar and pipe tobacco have been around for many centuries and have been commonly used by consumers worldwide. In recent times, with the rise of additive manufacturing technologies, commonly known as 3-Dimentional (3D) printing technology, it has been envisaged that printing technology may be for the manufacturing of tobacco products.

Extrusion is the most common and probably the simplest 3D printing technique. It is a process used to create different 3D objects of a fixed cross- sectional profile. The material to be extruded and shaped is usually provided in a substantially paste or gel form from a reservoir or container and forced under pressure through an extrusion nozzle or head which comprises an opening of a defined shape and cross-section according to which the extruded material is continuously shaped. Extrusion process not only allows very complex cross- section profile to be created, it also allows material which is brittle to be worked on. Tobacco products produced from extrusion process have already been reported in the art.

For instance patent document US 2008/0196731 relates to a method of processing tobacco fines, whereby the tobacco preparation for producing smoking articles from an initial material to be processed comprises tobacco fines and tobacco material. The tobacco material is subjected to an increased mechanical pressure (e.g. extrusion) in order to bind the tobacco fines permanently to the tobacco material without using external binding agent. Patent document WO 2007/138484 A2 relates to a consumable tobacco film strips adapted to dissolve in the oral cavity comprises tobacco component. The tobacco component preferably comprises ground or powdered tobacco laminae and/or stem (e.g., tobacco fines) having an average particle size of less than about 1mm. The tobacco film strips are not used for vaping or smoking.

Patent document CN 103 300 472 B relates to a new cigarette manufacturing method that uses 3D printing technology to produce cigarettes, and uses layered processing and superimposed solidification to add tobacco powder layer by layer to generate 3D solid cigarettes. Although it is possible to produce 3D tobacco products with extrusion process, it remains currently confidential, be it considering conventional extrusion processes or 3D printing technologies or else additive manufacturing technologies.

Meanwhile, numerous new kinds of tobacco products have emerged in recent years and the acceptance of these new products increases tremendously. It remains to be seen whether extrusion and/or 3D printing techniques will become more relevant for the manufacturing of these new tobacco products.

It is an aim of the invention to provide an improved extrusion and/or 3D printing process of tobacco containing substrates for the manufacturing of tobacco products, which may in particular be advantageous for the manufacturing of aerosol-generating articles of various kinds. Summary of the present invention

The inventors of the present invention have found solutions to the above-discussed problems through a new and inventive aerosol-generating tobacco containing substrate and its manufacturing method as defined in the claims.

A first aspect of the invention is accordingly to provide a method of manufacturing a 3-Dimensional aerosol-generating tobacco-containing substrate, comprising the steps of (a) Providing tobacco material(s); (b) Comminuting the tobacco material(s) into tobacco particles having an average particle size of less than 100 micrometres; (c) Collecting the tobacco particles having an average particle size of less than 100 micrometres, preferably between 30 micrometres and 90 micrometres; (d) Mixing the tobacco particles with at least one aerosol-generating agent, thereby forming an aerosol-generating tobacco- containing amorphous solid feedstock; (e) Dispensing the aerosol- generating tobacco-containing amorphous solid feedstock through a nozzle to form said 3-Dimensional tobacco-containing substrate, wherein the nozzle is heated at a temperature of at least 50°C and less than 100°C during dispensing.

A second aspect of the invention relates to a 3-Dimensional tobacco- containing substrate obtained by the method according to the present invention. The inventors of the present invention have experimented and confirmed that extrusion and 3D printing, or generally speaking additive manufacturing techniques can be used to produce 3D aerosol-generating tobacco-containing substrates for the making of aerosol-generating articles, and is particular for heat-not-burn tobacco products, wherein an aerosol-forming material, comprising usually a tobacco-containing material, is heated rather than combusted (heat-not-burn), to generate an inhalable aerosol.

Furthermore, thanks to the 3D aerosol-generating tobacco-containing substrate of the present invention and its manufacturing method, the inventors of the present invention have found out that aerosol-generating tobacco-containing substrates offer a very satisfactory sensory experience to users, even at low quantities of aerosol-generating tobacco-containing substrates per aerosol generating substrates, i.e. of a few tens of milligrams of substrate. Moreover, thanks to the smaller particle size (e.g. less than 100 pm) and increased homogenous overall product quality (which the tobacco-containing particles have been filtered and collected, as this is paramount for a superior quality of the end product), the increased particle surface (surface to volume ratio) leads to taste improvement and better aromatic release upon heating of the aerosol-generating tobacco-containing substrate. In this connection, the fact that the nozzle is heated at a temperature of at least 50 °C and less than 100 °C during dispensing is crucial especially in the present invention as it relates to an aerosol-generating substrate. The inventors found out that temperature higher than 100 °C is not suitable in producing 3D aerosol-generating tobacco-containing substrate of an aerosol-generating article as such high temperature would substantially reduce or destroy the characteristic of the tobacco products, thereby giving an inferior vaping experience, while moderately heated nozzle (above 50 °C) would be sufficient to allow a smooth dispensing of the feedback. For this reason, low temperature of nozzle (head) (i.e. less than 100 °C) is needed to be maintained during the entire dispensing process.

According to one particularly preferred embodiment, the tobacco material can be comminuted, having particle size between 30 pm and 90 pm, and said comminuted tobacco-containing particles are then filtered and collected such that only particle size of between 30 pm and 90 pm are being used for the production of the aerosol-generating tobacco-containing substrate. This narrow range of fine tobacco-containing particles are particularly preferred as it gives a more homogenous particle profile which is important to render better taste experience of the 3D extruded tobacco products.

According to one particularly preferred embodiment, a superior quality intermediate or end product can be obtained when the tobacco material can be comminuted, having particle size between 40 pm and 80 pm, and said comminuted tobacco-containing particles are then filtered and collected such that only particle size of between 40 pm and 80 pm are being used for the production of the aerosol-generating tobacco-containing substrate. A significant number of testers could significantly notice the particular fine (and smooth) vaping experience when the article comprises only tobacco material particles size within these range. It is noted that particle having too fine sizes (e.g. less than 40 pm or less than 20 pm) affect the general vaping experience as some odd tastes may be released from the overly comminuted tobacco material. According to another embodiment of the invention, the tobacco material(s) can be selected from the group consisting of tobacco fines, tobacco dust, tobacco laminae, tobacco cut filler, volume expanded tobacco, scrap tobacco which is recovered from various processing stages and cigarette manufacture stages, tobacco stems and stalks, scraps and/or sheets of reconstituted tobacco material, rolled tobacco stems, tobacco in whole leaf form, and the combination thereof. The inventors of the present invention found out that parts from tobacco which are tougher and harder (e.g. tobacco stems, stalks, cut filler, rolled tobacco stems) are suitable to be comminuted into smaller particle size e.g. less than 100 pm or 90 pm whereas softer parts (e.g. tobacco leaves, lamina portions, tobacco dust) can be comminuted into particle size less than 100 pm.

It is disclosed herein that in one particularly favoured embodiment, the tobacco material is selected only from tobacco cut filler. Cut filler tobacco product referred herein is formed predominantly from the lamina portion of the tobacco leaf, which is separated from the stem portion of the leaf during a threshing process. The inventors have found out that cut filler tobacco products, when the tobacco material is comminuted to particle size of less than 100 pm, preferably between 30 pm and 90 pm, the taste profile of the tobacco product can be enhanced. Similar results as described above can also be obtained when only the stem portion of the leaves is comminuted and homogenised.

According to yet another embodiment of the invention, the tobacco material(s) can be comminuted into tobacco-containing particles through milling, grinding, mulling, pulverizing, pounding, crushing and/or powdering. In another variant of the invention, the dispensing step comprises one or more of the following conditions: (a) Subjecting the mixture with a constant or an increasing pressure; (b) Subjecting the mixture with a constant or an increasing temperature; (c) Subjecting the mixture with a constant or an increasing flow rate or feed rate; (d) Subjecting the mixture with a constant or an increasing mechanical or shear force.

In another embodiment of the present invention further comprises a step of homogenising the mixture, wherein the mixture can be subjected to intense mixing for dispersion and homogenization of ingredients such as conveying, mixing, shearing, heating, cooling, shaping or encapsulation.

In another embodiment, the aerosol-generating agent in the feedstock mixture comprises at least one of a humectant, a foam stabilizing agent, and a foam forming agent or a combination thereof, wherein the aerosol-forming agent preferably has a weight of 10 - 80 wt. %. In a further embodiment, the feedstock mixture may comprise a binder, the binder being selected from the group consisting of alginate, guar, xanthan, acacia, pectin, hydroxyethyl bean gum, hydroxypropyl locust bean gum, tamarind or other gums, dextran, pullalon, konjac flour, derivative starch, modified cellulose compounds and a combination thereof. In a further embodiment, the feedstock mixture may further comprise additives, such as aromas, taste enhancers, preservatives or the like.

According to one embodiment, the tobacco-containing particles having an average particle size of less than 80 micrometres, preferably less than 70, 60, 50 or 40 micrometres are filtered and collected. According to one preferred embodiment, the feedstock has a moisture content before dispensing, of less than about 80 wt. %, preferably less than 70 wt. %, 60 wt. %, 50 wt. %, 40 wt. %, 35 wt. %, 30 wt. %, 25 wt. %, 20 wt. % or 15 wt. % based on the total weight of feedstock. In yet another embodiment, the dispensing comprises extruding the feedstock through the nozzle, preferably with a screw or piston extruder.

According to one embodiment, the nozzle has a dispensing aperture having, in a cross section perpendicular to feedstock dispensing direction, a smallest dimension of more than 1 mm and a largest dimension of less than 2 cm.

According to another embodiment, the aperture forms a die of a determined, regular or irregular shape.

In yet another embodiment, present invention further comprises a step of portioning the 3-Dimensional tobacco-containing substrate upon or after dispensing.

In one most preferred embodiment, the present invention further comprises a step of curing the formed 3-Dimensional aerosol-generating tobacco-containing substrate. According to another embodiment, the feedstock comprises a total solid content of at least 15 %, preferably between about 33 % and 66 % are total solid content.

According to another embodiment, at least 33 % of the total solid content of the feedstock content is tobacco-containing particles, preferably between 40 % and 70 % of the total solid content of the feedstock content.

According to another embodiment, the feedstock is dispensed by means through a nozzle aperture having a diameter of less than about 200 micrometres or less than about 150 micrometres.

According to another embodiment, the feedstock contains a first type of tobacco-containing particles, the method further comprising providing a further feedstock containing a second type of tobacco-containing particles to the first feedstock. According to another embodiment, the feedstock containing the first type of tobacco-containing particles and the feedstock containing the second type of tobacco-containing particles are subjected to the same or different device for printing.

By “about” or “approximately” in relation to a given numerical value, it is meant to include numerical values within 10% of the specified value. All values given in the present disclosure are to be understood to be complemented by the word “about”, unless it is clear to the contrary from the context.

The indefinite article “a” or “an” does not exclude a plurality, thus should be treated broadly.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

As used herein, the term “aerosol-generating tobacco-containing substrate” refers to substances or compounds capable of producing an aerosol comprising an aerosol-generating material that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol.

As used herein, the term "aerosol-generating" refers to a material capable of releasing volatile compounds upon heating, which can form an aerosol. The aerosol generated from aerosol-generating material of aerosol generating articles described herein may be visible or invisible and may include vapours (for example, fine particles of substances, which are in a gaseous state, that are ordinarily liquid or solid at room temperature) as well as gases and liquid droplets of condensed vapours. As used herein, the term “amorphous” refers to a substance or an element that is without a clearly defined shape or form. The term “solid” refers to a substance or an element that is solid rather than liquid or fluid, wherein paste, cream or mousse are considered as included in this term according to the present invention. The term “feedstock” refers to a raw material to supply to a machine or for producing an intermediate or an end product.

As used herein, wt.-% is to be understood as weight percent, based on the total weight of the composition or material, unless explicitly otherwise specified. In the present disclosure, all amounts are given in wt.-%, unless clearly stated otherwise or obvious from context. In the present disclosure, furthermore all amounts given in wt.-% in a particular composition add up to 100 wt.-%. The weight percent are thereby calculated by dividing the mass of each component by the total mass of the composition, unless indicated otherwise or clear from context.

Particle sizes, as disclosed in this invention, can be measured by any suitable method, e.g. sieving or laser diffraction, preferably sieving.

The term “smoking” and “vaping” should be construed as similar within the definition of the present invention.

Brief description of the drawings

Figure 1 shows a schematic representative of a 3D aerosol-generating article comprising tobacco-containing substrate having a cylindrical tubular shape.

Figure 2 shows a schematic representative of a 3D aerosol generating article comprising tobacco-containing substrate having an irregular shape.

Detailed description of the inventions Figure 1 is an example of the 3D aerosol-generating tobacco- containing substrate where the extruded 3D tobacco product 100 has a cylindrical tubular shape. The extruded tobacco product 100 shown in this example is an aerosol-generating article comprising tobacco-containing substrate. The extruded 3D aerosol-generating tobacco-containing substrate can be realised in many different forms other than the rod shape of Figure 1 , for instance cube, sphere, polygon or irregular shapes as demonstrated in the Figure 2. The length of the 3D aerosol-generating tobacco-containing substrate can be varied and only one or more selected portions of the extruded tobacco products may contain the tobacco-containing substrate.

In contrast to known methods for comminuting tobacco materials to particle size having size more than 100 pm, according to the present invention, selected tobacco materials are being comminuted, filtered and collected, wherein the particle size has an average size of less than 100 pm. In some embodiments, it is preferred to comminute the particle into even smaller size, for instance between 30 pm and 90 pm, or in some example to around 20 pm. The inventors of the present invention have found out that such smaller particulate size (i.e. between 30 pm and 90 pm) are particularly suitable for tobacco materials selected from for instance tobacco stalks, tobacco stems or cut filler, as these portions of the tobacco plants are generally more robust and tough compared to lamina portion of the tobacco for instance. Comminuting the particle size of these selected portions to less than 100 pm, in particular between 30 pm and 90 pm creates tobacco-containing particle having higher surface area for contacting aerosol former or carrier compounds. Moreover, filtering and collecting the particle having this size range allows the tobacco-containing substrate to be more homogenous.

The aerosol-generating articles which are produced from the extrusion process described herein is capable of producing an aerosol upon heating rather than combusting in order to release volatile compounds that can form said aerosol. The 3D aerosol-generating tobacco-containing substrate according to the present invention comprises aerosol-generating material for the generation of an aerosol. It is disclosed herein that the mixture for the extrusion process contains tobacco particles having particle size of less than 100 pm, preferably between 30 pm and 90 pm, and further comprises at least one of the following ingredients: a humectant, a binder, water, additive, aromatic and/or stabilizing agents. The aerosol-generating material comprises also an aerosol-forming agent, a foam-stabilizing agent, and a foam-forming agent, wherein the aerosol forming agent preferably has a weight of 10 - 80 wt.-%, more preferably around 25 %. The inventors of the present invention discover that the aerosol-generating material can be introduced into the mixture (or slurry) containing comminuted tobacco particles with the desired particle size as well as other ingredients without losing the stability of the aerosol-generating material.

The aerosol-forming agent can be selected from any compound, mixture and/or solution that is capable of forming an aerosol, e.g. when heated and/or in mixture with a tobacco ingredient containing agent. Well known examples include humectants such as glycerin and propylene glycol, 1, 3- Propanediol or compositions thereof, other alcohols, such as ethanol, etc.

In many extruder applications, conditioning is a step which cannot be completely ignored. Conditioning refers to setting a processing moistness using liquid such as water or water vapour. These necessary tasks are often completed in upstream processes or apparatus, wherein the ability of natural materials to quickly absorb steam and/or water, with good penetration, is utilised. The extruder apparatus are usually operated at ambient pressure. During extrusion, the tobacco-containing material (mixture) is exposed to shearing forces which result in desired or even undesired heating. According to the one embodiment of the present invention, the heating temperature of the material while dispensing is of about 50 °C to maximum less than 150 °C, preferably less than 100 °C. For this reason, the extruding nozzle may be cooled as applicable. The transport of material in the extruder is determined by the principles of drag flow, pressure flow and/or gap flow. The dissipative energy input is fed from the screw drive e.g. by converting electrical energy into thermal energy. Only as reference, the methods and conditions of extrusion as described in DE 10 2004 059 388 A1 and DE 10 2005 006 117 A1 are applicable to the present invention.

Advantageously, the total water present in the extruder is such that, when without an extrudate drying step being utilised, the moisture content of the cut extrudate is within a range of 5 % to 80 % by weight (wet basis) and more preferably within a range of between 40 % and 70 % or most preferably between 50 % and 60 % by weight (wet basis). By "total water" is meant the sum of any moisture present in the "dry" components fed to the extruder plus any added water. Water may be added to one or more of the components of the mixture before the components are fed to the extruder and/or by way of injection via a barrel port(s) of the extruder barrel. A convenient practice is to mix the components of the mixture and then to feed the mixture in a dry or substantially dry state to the extruder, water being added by injection into the extruder barrel. It will be appreciated that the 3D aerosol-generating tobacco- containing substrate 100 shown in the Figure 1 may be suitable for use with any types of existing heat-not-burn aerosol-generating devices.

The invention will be further described, by way of example only, with reference to the drawings of the accompanying Figures 1 and 2, which illustrate a schematic perspective view of a 3D aerosol-generating tobacco-containing substrate 100 obtained by a method according to the present invention.

Suitable tobacco material(s) for the purpose of extrusion are firstly selected. The selected tobacco material(s) are comminuted into desired particle size e.g. less than 100 pm or between 30 pm and 90 pm. The comminuted tobacco-containing particles are filtered and collected.

A mixture (or slurry) is prepared by mixing the collected tobacco- containing particles together other ingredients such as water, pectin, glycerine, humectant, water and aerosol-generating material, thereby forming an aerosol generating tobacco-containing amorphous solid feedstock. The total solid content of the mixture is about 35 % (65 % of the mixture comprises water). Of these solids, about 50 % are tobacco-containing particles.

The mixture is supplied to the printing or extruding head of an extruder application i.e. 3D printer, wherein the printing head has a nozzle aperture of about 140 micrometres. The printing head is heated to a temperature of about 90 °C. The mixture is dispensed from the printing head to form successive layers of 3D aerosol-generating tobacco-containing substrate 100 for use in smoking articles. The formed layers of the extruded tobacco objects are finally cured e.g. by hot air.