JP7586913B2 - Process for the preparation of sheets of alkaloid-containing material - Patent Application 20070123333 - Google Patents

Description

The present invention relates to a method for producing cast sheets of alkaloid-containing material.

In particular, the alkaloid-containing material is a homogenized tobacco material, preferably for use in an aerosol-generating article, such as a cigarette, or a "heat-not-burn" type tobacco-containing product.

Today, in addition to tobacco leaves, homogenized tobacco materials such as cast leaf or reconstituted tobacco are also used in the manufacture of tobacco products.

In "heat-not-burn" aerosol-generating articles, the aerosol-forming substrate is heated to a relatively low temperature to form an aerosol but prevent combustion of the tobacco material.

Homogenized tobacco material is produced by mixing different components, including tobacco powder, to form a tobacco slurry. Furthermore, the slurry generally contains fibers, such as cellulose fibers, in addition to those contained in the tobacco. This slurry is then stored in tanks before being sent through a suitable delivery system to a casting system where it enters a "casting box" to be cast onto the steel belt of a moving conveyor, and then dried in a dryer.

There is a need for processes to obtain alternative materials containing alkaloids that can be used for heat-free, non-combustion products.

In one aspect, the present invention relates to a method for the manufacture of a sheet of alkaloid-containing material, the method comprising the steps of providing a slurry comprising an alkaloid-containing material, an aerosol former and water, and extruding the slurry. The method may also comprise the steps of collecting the extruded slurry in a tank having an outlet, and providing a substrate sheet comprising fibers. The method may also comprise the steps of dispensing the slurry from the outlet onto the substrate sheet to form strips of the slurry, the substrate sheet forming, together with the strips of the slurry, a sheet of alkaloid-containing material.

The present invention also relates to a system for the manufacture of two or more sheets of material containing an alkaloid, the system comprising two or more bobbins of substrate sheets comprising fibers. The system may also include equipment for supplying a slurry to the two or more substrate sheets comprising fibers. The equipment may include an extruder adapted to extrude the slurry, a tank having a number of outlets adapted to contain the slurry, and a moving element adapted to move the two or more substrate sheets comprising fibers unwound from the two or more bobbins along a conveying direction and under the outlets such that the slurry is applied to the two or more substrate sheets.

The invention also relates to a system for the manufacture of sheets of material containing an alkaloid, the system comprising a bobbin of a substrate sheet comprising fibers and an installation for supplying a slurry to the substrate sheet comprising fibers. The installation may comprise an extruder adapted to extrude the slurry, a tank having an outlet adapted to receive the slurry from the extruder, and a moving element adapted to move the substrate sheet comprising fibers unwound from the bobbin along a conveying direction and under the outlet so that the slurry is applied to the substrate sheet.

The slurry is fed to a substrate sheet containing fibers to form a sheet of alkaloid-containing material. Thus, a "substrate of fibers" for the slurry is already present and there is no need to add large amounts of fibers to the slurry to obtain a sheet of alkaloid-containing material having a relatively high tensile strength. This aspect may allow for the use of less water in the slurry and therefore less energy in drying the resulting sheet of alkaloid-containing material.

As used herein, the term "sheet" means a layered element having a width and length substantially greater than its thickness.

As used herein, the term "slurry" refers to a liquid-like viscous or pasty material that may include an emulsion of different liquid-like viscous or pasty materials. A slurry may contain a certain amount of solid-state particles, provided that the slurry still exhibits liquid-like viscous or pasty behavior.

In what follows, the terms "upstream" and "downstream" are used to refer to the direction of slurry flow.

The term "movable support" as used herein means any means comprising a surface adapted to move in at least one longitudinal direction. The movable support may form a closed loop to provide uninterrupted transport capability in one direction. However, the movable support may move in a reciprocating manner as well. The movable support may comprise a conveyor belt. The movable support may be essentially flat. The movable support may exhibit a structured or unstructured surface. The movable support may comprise a sheet-like movable and bendable strip. The strip may be made of a metallic material, including but not limited to steel, copper, iron alloys, copper alloys, or rubber.

"Fiber-containing substrate sheet" means a sheet used as a substrate for a slurry and formed of a material that contains fibers. The material from which the sheet is formed may include any type of fiber, for example, cellulose fibers. The sheet of material may be placed on a movable support or may be self-supporting.

An "alkaloid-containing material" is a material that contains one or more alkaloids. The alkaloids may include nicotine. Nicotine may be found, for example, in tobacco.

Alkaloids are a group of naturally occurring compounds that contain mostly basic nitrogen atoms. The group also includes some related compounds that have neutral properties, and even some that have weakly acidic properties. Some synthetic compounds of similar structure are also called alkaloids. In addition to carbon, hydrogen, and nitrogen, alkaloids may also contain other elements such as oxygen, sulfur, and more rarely chlorine, bromine, and phosphorus.

Caffeine, nicotine, theobromine, atropine, and tubocurarine are examples of alkaloids.

As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco that contains the alkaloid nicotine. Thus, an alkaloid-containing material can be a homogenized tobacco material.

The most commonly used forms of homogenized tobacco material are reconstituted tobacco sheets and cast leaves. The process of forming homogenized tobacco material sheets typically involves mixing tobacco powder with a binder to form a slurry. The slurry is then used to create tobacco sheets, for example by casting the viscous slurry onto a moving metal belt to produce so-called cast leaves. Alternatively, slurries with lower viscosity and higher moisture content can be used to create reconstituted tobacco in a process similar to papermaking.

Tobacco sheet materials, which can be referred to as reconstituted sheet materials, can be formed using particulate tobacco or particulate tobacco blends, a humectant, and an aqueous solvent to form a tobacco composition.

The homogenized tobacco sheet may include, in addition to tobacco, a binder. The binder may be guar. The homogenized tobacco sheet may also include an aerosol former. The aerosol former may be glycerin.

The term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that may form an aerosol. Typically, the aerosol-forming substrate releases the volatile compounds upon heating. The aerosol-forming substrate may comprise an alkaloid-containing material that contains a volatile alkaloid flavour compound, which is released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may comprise a homogenised material. The aerosol-forming substrate may comprise a homogenised tobacco material.

As used herein, the term "aerosol generating device" refers to a device configured to interact with an aerosol-forming substrate to generate an aerosol. The aerosol generating device preferably includes an aerosolizer, such as a heater.

A sheet of alkaloid-containing material is therefore a sheet formed of material containing any alkaloid, or a combination of two or more alkaloids. The width of the sheet of alkaloid-containing material is preferably greater than about 10 millimeters, more preferably greater than about 20 millimeters or about 30 millimeters. Even more preferably, the width of the sheet of alkaloid-containing material is comprised between about 60 millimeters and about 2500 millimeters. The thickness of the sheet of alkaloid-containing material is preferably comprised between about 50 micrometers and about 300 micrometers, more preferably, the thickness of the sheet is comprised between about 100 micrometers and about 250 micrometers, and even more preferably, the thickness of the sheet is comprised between about 130 micrometers and 220 micrometers.

Sheets of alkaloid-containing material can be used as aerosol-forming substrates for aerosol generating devices.

The slurry may include a number of different components or ingredients. These components may affect the properties of the cast sheet of alkaloid-containing material. The first component is the alkaloid-containing material, for example in powder form. This material may be, for example, a tobacco powder blend. The tobacco powder blend preferably contains the majority of the tobacco present in the slurry. As such, the tobacco powder blend is the source of the majority of the tobacco in the homogenized tobacco material. As such, the tobacco powder blend defines the flavor to the final product, for example, the aerosol generated by heating the homogenized tobacco material. The amount of tobacco powder in the slurry preferably comprises about 20 percent to about 45 percent of the total mass of the slurry, i.e., the mass of the slurry including water. More preferably, the amount of tobacco powder in the slurry preferably comprises about 25 percent to about 45 percent of the total mass of the slurry, i.e., the mass of the slurry including water.

A binder is preferably added to the slurry to enhance the tensile properties of the homogenized sheet. An aerosol former is preferably added to the slurry to facilitate the formation of an aerosol. Additionally, water may be added to the slurry to reach a specific viscosity and moisture for casting a web of the alkaloid-containing material.

The amount of binder added to the slurry may comprise from about 0 percent to about 1 percent of the total mass of the slurry, i.e., the mass of the slurry including water. More preferably, the amount of binder added to the slurry comprises from about 0 percent to about 0.5 percent. The binder used in the slurry may be any of the gums or pectins described herein. The binder may ensure that the alkaloid powder remains substantially dispersed throughout the sheet of alkaloid-containing material. While any binder may be employed, preferred binders are natural pectins (such as fruit pectins, citrus pectins, or tobacco pectins), guar gums (such as hydroxyethyl guar, hydroxypropyl guar, etc.), locust bean gums (such as hydroxyethyl locust bean gum, hydroxypropyl locust bean gum, etc.), alginates, starches (such as modified or derivatized starches), celluloses (such as methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, carboxymethylcellulose, etc.), tamarind gum, dextran, pralon, konjac flour, xanthan gum, and the like. A particularly preferred binder for use in the present invention is guar.

Suitable aerosol formers for inclusion in slurries for sheets of alkaloid-containing material are well known in the art and include, but are not limited to, monohydric alcohols (such as menthol), polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.).

Examples of preferred aerosol formers are glycerin and propylene glycol.

The slurry may have an aerosol former content of about 1 percent to about 5 percent of the total mass of the slurry, i.e., the mass of the slurry including water. The aerosol former content is preferably 1 to 3 percent of the total mass of the slurry, which corresponds to an amount of aerosol former of about 2.9 percent to about 8.5 percent on a dry weight basis of the slurry.

Water is also preferably present in the slurry. The amount of water preferably comprises about 30 percent to 55 percent of the total mass of the slurry, i.e., the mass of the slurry including the water. More preferably, the amount of water comprises about 45 percent to 55 percent of the total mass of the slurry, i.e., the mass of the slurry including the water.

The alkaloid-containing material, preferably in powder form, may contain cellulose. However, it is preferred that no cellulose fibre is added to the slurry, i.e. no further fibre is added to the slurry other than that already contained in the alkaloid-containing material. Thus, it is preferred that the amount of fibre added to the slurry (i.e. in addition to that already contained in the alkaloid-containing material) is less than 0.5 percent of the total mass of the slurry, i.e. the mass of the slurry including water. More preferably, the added fibre is present in an amount less than about 0.1 percent of the total mass of the slurry.

The slurry is formed at a given location. The slurry may then be stored. The slurry can be stored and formed at the same location, e.g., in the same storage tank, or can be stored and formed at two different locations, e.g., in two different storage tanks. The storage tanks used are preferably well known in the art. Furthermore, the slurry can be formed or stored in a single storage tank or in multiple storage tanks. A mixer is preferably present in the storage tank to homogenize the slurry.

The slurry is transferred from the storage tank to the extruder. The slurry is introduced, for example, into the inlet of the extruder and exits the extruder at the outlet of the extruder. There may be more than one inlet and more than one outlet of the extruder. The extruder may include a screw, the rotation of which may cause compression of the slurry. A heating element may be present in the extruder to heat the slurry. The rotation of the screw may also cause heating of the slurry. The extruder may include a single screw extruder. Thus, extrusion here may include compressing the slurry by the screw. Due to compression, the slurry is directed towards the outlet of the extruder. After extrusion, the slurry is still in slurry form. The extrusion process preferably reduces the viscosity of the slurry.

In this context, the term "extrusion" is used in its ordinary sense, i.e. "to force or push out, expel." The slurry after extrusion remains in slurry form.

The extruded slurry is collected in a tank having an outlet. The tank has a bottom wall, and the outlet is preferably formed in the bottom wall. The outlet preferably comprises an opening formed in the bottom wall of the tank. The tank may be located below the extruder. The tank may be integral with the extruder.

There may therefore be two configurations. In the first configuration, the slurry is introduced into a vessel. The vessel contains a screw that compresses the slurry towards an outlet. The vessel and screw may be considered to be an extruder. The compressed slurry leaving the vessel is introduced into a tank. From the tank outlet or from the tank outlets, the slurry is fed to a substrate sheet or to two or more substrate sheets.

In a second configuration, the screw is contained within the tank. In other words, the tank is part of the extruder and the screw is located inside the tank. The slurry is introduced into the tank. The slurry is then compressed by the screw. The tank and the screw form the extruder. The compressed slurry leaves the tank through an outlet or outlets of the tank. From the outlet of the tank, the slurry is fed onto the substrate sheet or two or more substrate sheets.

In both configurations, the slurry is output from the tank's outlet or outlets.

Further, a substrate sheet comprising the fibers is provided. The substrate sheet defines a surface onto which the slurry is dispensed from the tank. The surface may be horizontal, i.e. parallel to the horizontal plane, or it may be inclined. It may also be substantially vertical. The substrate sheet may be provided on a bobbin from which it is unwound.

The base sheet moves along the transport direction.

The tank including the outlet is preferably positioned above the base sheet. More preferably, the outlet is positioned above the base sheet.

The substrate sheet containing the fibers is typically a relatively "strong" sheet, the tensile strength of which is such that it can be transported between rollers without the need for any additional substrate on which it must be in contact. The tensile strength of the substrate sheet is preferably comprised between about 0.1 Newtons/(mm) ² and about 1 Newtons/(mm) ² .

The substrate sheet may be made of different materials, natural or synthetic, including cellulose, hemp, kenaf, bamboo pulp, cotton, silk, or combinations thereof. The choice of material is made according to the mechanical properties expected of the final sheet containing the alkaloid-containing material.

The fiber content in the base sheet is preferably less than 50 grams per ^meter .

Cellulosic fibers forming the sheets are well known in the art and may include, but are preferably not limited to, softwood fibers, hardwood fibers, jute fibers, flax fibers, tobacco fibers, and combinations thereof. In addition to pulping, the cellulose fibers may be subjected to suitable processes such as refining, mechanical pulping, chemical pulping, bleaching, sulfate pulping, and combinations thereof. The cellulose fibers may include tobacco stem material, petioles, or other tobacco plant materials. Cellulosic fibers such as wood fibers preferably include a low lignin content. Alternatively, fibers such as vegetable fibers may be used in conjunction with or as a replacement for the above fibers, including hemp and bamboo.

The fiber-containing substrate sheet preferably comprises fibers having an average fiber length comprised between 0.7 millimeters and about 50 millimeters. More preferably, the fibers of the fiber-containing substrate sheet have an average fiber length comprised between about 1 millimeter and about 25 millimeters. More preferably, the fibers of the fiber-containing substrate sheet have an average fiber length comprised between about 1 millimeter and about 10 millimeters. More preferably, the fibers of the fiber-containing substrate sheet have an average fiber length comprised between about 1 millimeter and about 5 millimeters. Even more preferably, the fibers of the fiber-containing substrate sheet have an average fiber length comprised between about 1.2 millimeters and about 1.8 millimeters.

The average length of fibers refers to their actual length (regardless of whether they are curled or kinked) as measured by MORFI COMPACT commercialized by Techpap SAS. The average length is the mathematical average of the fiber lengths measured by MORFI COMPACT for measurements of N fibers (where N>5). MORFI COMPACT is a fiber analyzer that measures the length of fibers according to the structure of the fiber, and therefore measures the actual generated length of the fiber. A measured object is considered a fiber if its length is comprised between 200 micrometers and 10,000 micrometers and its width is comprised between 5 micrometers and 75 micrometers. The length of the fiber is measured when deionized water is added to the fiber and the Morfi software is used.

The fibers in the substrate sheet may be woven or non-woven. If non-woven, the fibers may be oriented primarily in one direction. Also, the fibers may be, for example, randomly oriented. If woven, a variety of patterns may be used.

The substrate sheet defines a first surface and a second surface. For example, the first surface or the second surface may be a substantially planar surface. The first surface and the second surface may be opposite one another. The substrate sheet is preferably moved to apply or distribute the slurry present in the tank to the first surface of the substrate sheet such that the slurry is applied to the first surface along the length of the first surface to form strips of slurry on the substrate sheet including the fibers.

The slurry does not have to be applied to the entire first surface. The slurry can be applied to only a portion of the first surface (e.g., a central portion of the first surface).

Therefore, it is preferable that the base sheet is moved along the conveying direction (e.g., moved linearly) so that a portion of the first surface of the base sheet comes into contact with the slurry.

The slurry that comes into contact with the base sheet may be completely absorbed by the base sheet. The slurry may form a coating on the first surface of the base sheet. The slurry may be partially absorbed by the base sheet and may also partially coat the first surface of the base sheet. The resulting sheet formed by the base sheet and the slurry may have different compositions in a cross section taken perpendicular to the first surface of the base sheet. The lowest amount of slurry may be present at the second surface. The highest amount of slurry may be present at the first surface. In between, the combination of the material of the base sheet and the slurry may be present in different concentrations.

A moving element may be provided for moving the substrate sheet along the conveying direction. The moving element may include a movable support, and the substrate sheet including the fibers may be positioned on the movable support so as to convey the substrate sheet while the movable support moves.

In another embodiment, the moving element may include a moving drum that moves the substrate sheet as it rotates. The support sheet may be free-standing for a portion of its length.

The amount of slurry in the tank is preferably kept substantially constant. For example, the amount of slurry in the tank is equal to a predefined amount. The amount of slurry in the tank is preferably kept constant. For example, a predetermined level of slurry in the tank is set. To obtain a substantially constant level of slurry in the tank, the slurry is continuously fed into the tank while being fed onto the substrate sheet. The level of the slurry in the tank may be checked by a sensor and the amount of slurry provided into the tank by the extruder may be varied to maintain the level in the tank constant.

As previously described, the slurry is dispensed from the tank outlet onto the substrate sheet. The slurry forms a deposit on a first surface of the substrate sheet.

Further, due to the movement of the substrate sheet in the conveying direction, the slurry dispensed from the outlet forms slurry strips. The combination of the substrate sheet and the slurry strips provided on its first surface forms a sheet of material containing the alkaloid.

In addition to the base sheet and the strips of slurry, other elements may be combined to form a sheet of material containing the alkaloid. The base sheet itself may be a multi-layer sheet. The base sheet may include a flavor sheet, a sheet of material containing nicotine, and others.

Forming a sheet of alkaloid-containing material by feeding the slurry onto a substrate sheet containing already formed fibers allows for the substantial elimination of the fibers added in the slurry. Fibers are generally added to the slurry to increase the tensile strength of the sheet and act as reinforcing agents.

However, the presence of the substrate sheet onto which the slurry is applied provides sufficient tensile strength to the resulting sheet of alkaloid-containing material. The addition of cellulose fibers into the slurry may be avoided.

In slurries where fibers are added, a relatively large amount of water may be required in the slurry, since water is required for pulping of the fibers. In addition, due to the large amount of water present in the slurry, a large amount of energy is required to dry the slurry and form a sheet of material containing the alkaloids. In this "high water content" process, the conveyor steel belt on which the slurry is cast may also play an important role: any defects in the conveyor belt may be transferred to the cast sheet, and therefore a high quality belt is often required. Removing the fibers from the slurry allows a reduction in the amount of water required to homogenize the slurry. For good homogenization, a certain amount of water may still be required. This amount of water may be further reduced later by the extrusion process. This relatively "high density" slurry is suitable for application to a substrate sheet containing fibers.

Shorter drying times or less drying power are required for drying of the sheets of alkaloid-containing material produced according to the invention. The substrate sheet is preferably already dry when wound on the bobbin. The substrate sheet may be moistened (e.g., water may be sprayed onto the substrate sheet) before contacting the slurry. Moistening is done to facilitate penetration of the slurry in the substrate sheet. The resulting multi-layered sheets of alkaloid-containing material, or sheets of alkaloid-containing composite material, are only "partially wet" and the drying time or amount of energy required for drying is relatively low. Less "intense" drying allows one to have better control of the flavor of the aerosol generated by the sheets of alkaloid-containing material when used as an aerosol-forming substrate. During drying, alkaloids, flavors, or other volatiles may evaporate and their concentration in the sheets of alkaloid-containing material may be reduced. Minimizing drying when alkaloids are present helps to control the aerosol properties. Smaller dryers may be required compared to those used to dry cast leaves. Energy may be saved. Installation space may be saved.

The tank preferably includes a plurality of outlets, and the step of dispensing the slurry from the outlets preferably includes dispensing the slurry from the plurality of outlets to form a plurality of strips of slurry. All of the plurality of outlets are preferably formed on the bottom wall of the tank. Due to the plurality of outlets, two or more single slurry strips may be created. A single substrate sheet including fibers may be provided on which a number of slurry strips are dispensed equal to the number of outlets formed on the tank. The single substrate sheet having the plurality of slurry strips on its surface may be cut into sub-sheets. Alternatively, a single slurry strip may be formed on the substrate sheet and other slurry strips may be formed elsewhere. Thus, the substrate sheet may include one or more than one strip of slurry. The plurality of slurry strips are preferably parallel to each other.

For example, if a movable support is present, the slurry strips may be formed on a substrate sheet, or the slurry strips may be formed on the movable support.

More preferably, the step of feeding the slurry from the multiple outlets includes feeding the slurry from the multiple outlets onto two or more substrate sheets comprising fibers to form two or more sheets of material containing the alkaloid. Preferably, two or more sheets of material containing the alkaloid are formed simultaneously. Two or more substrate sheets comprising fibers may be provided. The number of substrate sheets may be equal to or different from the number of outlets formed in the tank. Thus, in each substrate sheet, a single strip of slurry may be formed, or two or more strips of slurry may be formed, or no strips of slurry may be formed. If the number of substrate sheets is equal to the number of outlets formed in the tank, a single strip of slurry may be formed. If the number of substrate sheets is less than the number of outlets, two or more strips of slurry may be formed. The step of slitting the "wide" sheet of material containing the alkaloid into narrower sheets may be avoided. This process requires fewer components (such as slit blades). Machines such as dryers may be smaller.

Furthermore, in cases where the number of substrate sheets is equal to the number of outlets in the tank, the substrate sheets may also be positioned such that no slurry is dispensed onto some substrate sheets while two or more strips of slurry are formed on other substrate sheets.

In the case of two or more substrate sheets, the substrate sheets may be identical to one another. In particular, the substrate sheets may all have the same thickness. The substrate sheets may all have the same width.

The thickness of the substrate sheet is preferably from about 175 micrometers to about 250 micrometers. More preferably, the thickness of the substrate sheet is from about 190 micrometers to about 220 micrometers. The width of the substrate sheet is preferably from about 100 millimeters to about 150 millimeters.

The step of dispensing the slurry from the multiple outlets preferably includes spraying the slurry onto the substrate sheet. The step of dispensing the slurry from the multiple outlets preferably includes spraying the slurry onto at least one of the two or more substrate sheets. The step of dispensing the slurry from the multiple outlets preferably includes spraying the slurry onto all of the two or more substrate sheets. The nozzle preferably discharges the slurry from the tank onto the substrate sheet, preferably onto the surface of the substrate sheet comprising fibers, preferably onto the surface of the two or more substrate sheets. The slurry present in the tank may be very viscous, for example having a kinematic viscosity comprised between about 18,000 centipoise and about 45,000 centipoise, and for this reason it is preferred to provide one or more pumps to push the slurry towards the outlet of the tank. A nozzle is preferably located at each outlet.

The step of dispensing the slurry from the multiple outlets preferably includes depositing the slurry on the substrate sheet. The step of dispensing the slurry from the multiple outlets preferably includes depositing the slurry on at least one of the two or more substrate sheets. The step of dispensing the slurry from the multiple outlets preferably includes depositing the slurry on all of the two or more substrate sheets. Dispensing the slurry on the substrate sheet may be by gravity alone. A roller may be positioned at each outlet. The roller may be in contact with the substrate sheet containing the fibers. The slurry falls by gravity from the tank into the outlet and then onto the roller. In this way, the roller coats the substrate sheet, or two or more substrate sheets, with the slurry.

The method preferably includes adjusting the pressure or flow rate of the slurry provided from the outlet. The method preferably includes adjusting the pressure or flow rate of the slurry provided from at least one of the plurality of outlets. The method preferably includes adjusting the pressure or flow rate of the slurry provided from all of the plurality of outlets. Even more preferably, adjusting the pressure or flow rate of the slurry provided from at least one of the plurality of outlets independently of at least one of the other outlets of the plurality of outlets. Given N outlets, selecting one outlet from among the available N, the pressure or flow rate of the slurry exiting the selected outlet is independent of at least one of the pressures or flow rates of the slurry exiting the other N-1 outlets. The flow rate or pressure of the slurry is independently adjusted at all of the plurality of outlets. At least one of the plurality of outlets preferably includes a pump for adjusting the pressure or flow rate of the slurry exiting the outlet. More preferably, each of the plurality of outlets includes a pump for adjusting the pressure or flow rate of the slurry exiting the outlet. Preferably, both pressure and flow rate may be adjusted at each outlet independently from at least another outlet of the plurality of outlets.

The method preferably includes a step of reducing the amount of water in the slurry while extruding. The method preferably includes a step of reducing the amount of water in the slurry while compressing the slurry with a screw. During the extrusion process, the amount of water in the slurry may be reduced. This is due to, for example, the heat and pressure present during the extrusion process. Reducing the water in the slurry may allow for a denser slurry to be obtained that requires less time and energy to dry when the slurry is applied to the substrate sheet. In this way, control of the resulting flavor and alkaloid concentration in the resulting sheet of alkaloid-containing material may be obtained. The amount of water removed during extrusion is preferably less than about 50 percent of the total mass of the slurry. The amount of water removed during extrusion is preferably less than about 25 percent of the total mass of the slurry. The amount of water removed during extrusion is preferably less than about 15 percent of the total mass of the slurry. The amount of water removed during extrusion is preferably greater than about 2 percent of the total mass of the slurry. More preferably, the amount of water removed during extrusion is greater than about 4 percent of the total mass of the slurry.

After extrusion, the amount of binder (by weight) remains substantially the same as before extrusion. After extrusion, the amount of aerosol former (by weight) remains the same as before extrusion. After extrusion, the amount of alkaloid-containing material (by weight) remains the same as before extrusion. After extrusion, the amount of water is preferably reduced from about 30 percent to about 55 percent of the total mass of the slurry before extrusion to about 30 percent to 50 percent of the total mass of the slurry.

The method preferably includes using a component to orient the flow of slurry provided from one or more of the plurality of outlets along the direction of movement of the substrate sheet. The tank outlet preferably has a particular shape. At least one of the plurality of outlets may comprise a pipe or nozzle having a curvature. For example, the pipe or nozzle may have an arcuate configuration. A curved nozzle is preferably provided. The curvature is adapted to impart a non-zero component to the flow of slurry exiting the pipe or nozzle along an axis parallel to the conveying direction of the substrate sheet.

The method preferably includes evaluating the thickness of the sheet of alkaloid-containing material. The method preferably includes evaluating the thickness of at least one of the sheets of two or more alkaloid-containing materials. The method preferably includes evaluating the thickness of all of the sheets of two or more alkaloid-containing materials. The method preferably includes compressing the sheet of alkaloid-containing material. The method preferably includes compressing at least one of the sheets of two or more alkaloid-containing materials. The method preferably includes compressing all of the sheets of two or more alkaloid-containing materials. More preferably, the method includes modifying the thickness of the sheet of alkaloid-containing material by compressing the sheet of alkaloid-containing material. More preferably, the method includes modifying the thickness of the sheet of alkaloid-containing material by compressing at least one of the sheets of two or more alkaloid-containing materials. More preferably, the method includes modifying the thickness of the sheet of alkaloid-containing material by compressing all of the sheets of two or more alkaloid-containing materials. The compressing step may include a calendering step. The compressing step may be performed by inserting the sheet of alkaloid-containing material between two compression rollers. The thickness of the sheet may be checked after the slurry is deposited and dried. The thickness of the sheet may be measured by an optical sensor. Suitable optical sensors may include X-ray or laser sensors, or a combination thereof. A feedback loop may be provided to correct the thickness of the sheet if the measured thickness is outside the desired range.

The step of providing a slurry containing an alkaloid-containing material, an aerosol former, and water preferably includes at least one of providing the alkaloid-containing material to the slurry in an amount of about 40 percent to about 70 percent of the total weight of the slurry, providing water to the slurry in an amount of about 30 percent to about 55 percent of the total weight of the slurry, providing a binder to the slurry in an amount of about 0 percent to about 1 percent of the total weight of the slurry, and providing an aerosol former to the slurry in an amount of 1 percent to about 5 percent of the total weight of the slurry.

More preferably, the step of providing the alkaloid-containing material to the slurry includes providing the alkaloid-containing material to the slurry in an amount comprising about 40 percent to about 50 percent of the total weight of the slurry.

More preferably, the step of providing water to the slurry includes providing water to the slurry in an amount comprising about 45 percent to about 55 percent of the total weight of the slurry. Due to the relatively low amount of water in the sheet of alkaloid-containing material, the drying time required is relatively short compared to a cast sheet. Minimal loss of volatiles from the sheet may be achieved.

More preferably, the step of providing a binder to the slurry includes providing the binder to the slurry in an amount comprised between about 0 percent and about 0.5 percent of the total weight of the slurry. The amount of binder may depend on the desired properties of the sheet of alkaloid-containing material. If it is desired that the slurry be largely absorbed by the substrate sheet, less binder may be used to improve absorption. If a coating of the slurry on the substrate sheet is preferred, a greater amount of binder may be used. The amount of binder may change the viscosity of the slurry. A greater amount of binder may lead to a higher viscosity of the slurry.

More preferably, the step of providing the aerosol former to the slurry includes providing the aerosol former to the slurry in an amount comprising 1 percent to about 3 percent of the total weight of the slurry.

The step of providing a slurry comprising an alkaloid-containing material, an aerosol former, and water preferably includes grinding the alkaloid-containing material to a powder having a size comprised between about 8 micrometers and 200 micrometers. More preferably, the step of providing a slurry comprising an alkaloid-containing material, an aerosol former, and water includes grinding the alkaloid-containing material to a powder having a size comprised between about 10 micrometers and 150 micrometers. Even more preferably, the step of providing a slurry comprising an alkaloid-containing material, an aerosol former, and water includes grinding the alkaloid-containing material to a powder having a size comprised between about 15 micrometers and 120 micrometers. The size of the powder does not need to be "extremely small" due to the fact that the slurry contains no or only very small amounts of cellulose fibers in addition to the cellulose fibers already contained in the alkaloid-containing material. In order to obtain a homogeneous slurry, the particles of the alkaloid-containing material are preferably "small". This small size is also due to the absence of added fibers, which act as a "glue" in the cast leaf. Preferably, the size of the ground particles of the alkaloid-containing material is less than 200 micrometers, preferably less than 180 micrometers, preferably less than 160 micrometers, preferably less than 140 micrometers, preferably less than 120 micrometers, preferably less than 100 micrometers, preferably less than 80 micrometers, preferably less than 60 micrometers, preferably less than 40 micrometers. Preferably, the size of the ground particles of the alkaloid-containing material is greater than 8 micrometers, preferably greater than 12 micrometers, preferably greater than 20 micrometers, preferably greater than 30 micrometers, preferably greater than 50 micrometers, preferably greater than 70 micrometers.

The size of the particles of the alkaloid-containing material refers to the Dv95 size. Each of the values listed above indicates the Dv95 of the particle size. The "v" in Dv95 means that the volume distribution is taken into account. The use of the volume distribution introduces the concept of an equivalent sphere. An equivalent sphere is a sphere that is equivalent to the actual particle in the property we are measuring. It is therefore a sphere that will produce the same scattering intensity in light scattering methods as the actual particle. This is essentially a sphere with the same volume of particles. Furthermore, the "95" in Dv95 refers to the diameter where 95 percent of the distribution has a smaller particle size and 5 percent has a larger particle size. The particle size is therefore that size by volume distribution where 95 percent of the particles have a diameter smaller than the stated value (the diameter of a corresponding sphere with substantially the same volume of the particle). A particle size of 60 micrometers means that 95 percent of the particles have a diameter smaller than 60 micrometers and the diameter is the diameter of a sphere with a corresponding volume than the particle.

The Dv95 size of particles is measured using a Horiba LA950 or LA960 particle size distribution analyzer. The HORIBA LA-960 particle size analyzer measures size distribution using laser diffraction. This technique uses first principles to calculate size using light scattered off the particle (edge diffraction) and light transmitted through the particle (secondary scattering refraction). The LA-960 incorporates Mie scattering theory.

Furthermore, the viscosity of the slurry may depend on the size of the powder of the alkaloid-containing material. The larger the size, the more viscous the slurry may be.

The method preferably includes providing a substrate sheet having fibers with an average fiber length of about 0.7 millimeters to about 50 millimeters. The method preferably includes providing at least one of the two or more substrate sheets having fibers with an average fiber length of about 0.7 millimeters to about 50 millimeters. The method preferably includes providing all of the two or more substrate sheets having fibers with an average fiber length of about 0.7 millimeters to about 50 millimeters. More preferably, the fibers of the substrate sheet including fibers have an average fiber length of about 1 millimeter to about 25 millimeters. More preferably, the fibers of the substrate sheet including fibers have an average fiber length of about 1 millimeter to about 10 millimeters. More preferably, the fibers of the substrate sheet including fibers have an average fiber length of about 1 millimeter to about 5 millimeters. Even more preferably, the fibers of the substrate sheet including fibers have an average fiber length of about 1.2 millimeters to about 1.8 millimeters.

The base sheet is preferably a braided sheet. A braided sheet is a sheet in which fibers are intertwined. It is not necessary for all the fibers to be intertwined, but some of them will be. A braided sheet makes it possible to obtain a homogeneous and relatively high mechanical strength.

The step of extruding the slurry and collecting the extruded slurry in a tank with multiple outlets preferably includes extruding the slurry by a screw. The extrusion of the slurry is preferably performed in a single screw extruder. Single screw extrusion creates pressure in the slurry. This forces the slurry to be extruded. Single screw extruders can be used as part of a larger extrusion system or as a stand-alone machine for extrusion. The screw may be located in a hot barrel. As the screw rotates, it moves the slurry in the hot barrel. In this way, the slurry not only reaches the required temperature but also is thoroughly mixed to form a homogenous slurry. The pressure built up by the single screw extruder then forces the slurry out of the extruder. Extrusion includes compressing the slurry by a screw. More preferably, the step of extrusion includes inserting the slurry into a single screw extruder. Although the slurry exits at the extruder outlet, the process is still considered to be extrusion. The tank may be part of the extruder or it may be external to the extruder.

The method preferably includes a step of homogenizing the extruded slurry collected in a tank. The slurry exiting the extruder enters the tank. Alternatively, the tank is part of the extruder and the extruded slurry is collected in the part of the tank from which the slurry was extruded. The slurry is preferably mixed or otherwise agitated in the tank. Agitation or mixing may improve the homogeneity of the slurry. The slurry is preferably made uniform throughout its structure or composition. Thus, the composition of the slurry and the properties of the slurry (viscosity, temperature, etc.) are the same throughout the tank. In this way, the slurry from every outlet, delivered by the multiple outlets, is substantially the same. When two or more sheets of material containing alkaloids are formed by the method of the present invention, all sheets have substantially the same properties, since the slurries output from the outlets have the same properties (assuming multiple identical substrate sheets are used).

The step of supplying the slurry from the multiple outlets to form multiple parallel strips of slurry preferably includes providing a moving drum located below the multiple outlets, unwinding one or more bobbins to obtain one or more base sheets containing fibers, placing one or more base sheets containing fibers on the moving drum so as to move the one or more base sheets along the moving direction, and supplying the slurry from the multiple outlets onto the one or more base sheets containing fibers while the one or more base sheets containing fibers are moved along the moving direction by the moving drum. The step of supplying the slurry from the multiple outlets to form multiple parallel strips of slurry preferably includes providing a moving drum located below the multiple outlets, unwinding two or more bobbins to obtain two or more base sheets containing fibers, placing two or more base sheets containing fibers on the moving drum so as to move the two or more base sheets along the moving direction, and supplying the slurry from the multiple outlets onto the two or more base sheets containing fibers while the two or more base sheets containing fibers are moved along the moving direction by the moving drum.

The one or more substrate sheets are preferably self-supporting. The rotation of the moving drum then moves the one or more substrate sheets. When the movement is provided, no conveyor belt is needed to support the substrate sheets. The one or more substrate sheets comprising the fibers can be "self-supporting". The second surface of the one or more substrate sheets opposite the first surface facing the outlet of the tank is preferably not in contact with any further elements for at least a certain length interval. The substrate sheets may proceed "free-standing" after the slurry is dispensed, without both sides being in contact with any other elements. The fact that a conveyor belt is substantially no longer needed to support the sheets of alkaloid-containing material allows for greater flexibility of the entire system. In the process in which the slurry is cast on the conveyor belt, a conveyor belt with strict dimensional requirements is generally needed. Such a belt may no longer be needed when a self-supporting substrate sheet is used.

Specific embodiments are further described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 shows a schematic perspective view of an installation for the production of sheets of alkaloid-containing material according to the invention. FIG. 2 shows a front view of the installation of FIG. FIG. 3 shows a side view of the installation of FIGS. FIG. 4 shows an enlarged view of a detail of the installation of FIGS.

Referring initially to Figures 1 and 2, an apparatus for the manufacture of sheets 200 of alkaloid-containing material according to the present invention is shown and designated by the reference numeral 100.

The apparatus 100 is preferably adapted for the production of a plurality of sheets 200 of material containing an alkaloid. In this embodiment, the plurality of sheets are sheets of homogenized tobacco material.

The equipment 100 for producing sheets of homogenized tobacco material includes an extruder 2, a tank 3 positioned at the outlet 20 of the extruder 2, and a moving drum 4 located below the tank 3.

The extruder 2 comprises an inlet 21 into which a slurry 22 (indicated by an arrow in FIG. 1) for forming a sheet of homogenized tobacco material is introduced, a screw 23 for extruding the slurry, and an outlet 20. The slurry 22 is pushed from the inlet to the outlet 20 by the screw 23 (see again the arrow 22). The screw 23 pushing the slurry 22 may be rotated by a motor 24 (see, for example, FIG. 2).

The slurry 22 reaches the extruder 2 from different storage tanks or silos (not shown in the accompanying drawings). The slurry 22 comprises tobacco powder, water, a binder and an aerosol former. The binder is preferably guar. The aerosol former is preferably glycerin. Preferably, no further fibres are added to the slurry.

The slurry 22 has the following composition at the inlet in its total mass:
Water: 30% to 55%
Tobacco powder: 40% to 70%
Binder: 0% to 1%
Aerosol former: 1% to 5%
Added fiber: less than 0.5%

The slurry 22 reaches the tank 3 from the extruder 2. From the above composition, 5% of the water is removed from the slurry by the extrusion process.

The tank 3 includes multiple outlets, all indicated at 30. The tank 3 may have any geometric shape, and in the illustrated embodiment is substantially conical. The tank 3 includes a side wall 32 and further includes a bottom wall 33. A mixer 34 (indicated by an arrow in FIG. 1) may be present inside the tank 3 to agitate and mix the slurry.

Additionally, a sensor 50 is present in the tank 3 to measure the vertical level of the slurry. Preferably, there is feedback between the sensor 30 and the extruder 2 so that the slurry is maintained at a substantially constant level in the tank 3.

Below the outlet 30 is located the moving drum 4. The moving drum 4 is adapted to rotate about its axis 6 in a rotational direction 5 indicated by an arrow in Figures 1 and 2. The moving drum 4 defines an outer cylindrical surface 41.

Furthermore, the installation 100 includes a plurality of bobbins 7. Each bobbin 7 of the plurality of bobbins is made of a coil of a base sheet 8, for example a cellulose fiber sheet. The bobbins are unwound and the free portion of the sheet 8 unwound from the bobbins 7 is positioned in contact with the moving drum 4. The base sheet 8 includes a first surface 11 and a second surface 1, one surface opposite to the other surface. The second surface 1 is preferably in contact with the cylindrical surface 41 of the moving drum 4. The first surface 11 faces at least one of the plurality of outlets 30. The rotation of the moving drum 4 causes the movement of the plurality of base sheets 8 along a common conveying direction indicated by the arrow 12 in Figs. 1 and 3. Thus, the bobbins 7 are unwound continuously by the rotation of the drum 4.

Each substrate sheet 8 of the plurality of substrate sheets is in contact with the surface 41 of the moving drum 4 and is free-standing downstream of the drum 4 along the conveying direction, i.e. the first surface 11 and the second surface 1 are not supported by any element. Further drums or rollers (not visible in the drawing) may further pull the plurality of sheets 8 in the conveying direction 12.

The slurry 22 is delivered to the plurality of substrate sheets 8 through the outlets 30. Each outlet 30 of the plurality of outlets 8 preferably delivers the slurry 22 to a single substrate sheet 8 of the plurality of sheets, as seen in FIG. 2. The slurry is delivered from the outlets 30 by gravity or by application of pressure, for example by a pump 31. The slurry from the tank 3 is moved by the pump 31 from the tank 3 through the plurality of outlets 30 to the substrate sheets 8. The pump 31 preferably includes a flow control (not visible in the drawing) to control the amount of slurry delivered to the substrate sheets 8.

When the slurry 22 is applied to the base sheet, it becomes a homogenized tobacco sheet 200. The slurry may be partially or completely absorbed by the base sheet 8. Most of the slurry may coat the base sheet 8, particularly the second surface 11.

In one embodiment, the bottom wall 33 of the tank 3 is formed with a number of openings 35, each connected to a pipe 36 (see Figures 2 and 3). A valve 37 regulates the flow of the slurry through the pipe 36. Downstream of the valve 37 in the direction of the slurry flow, the pipe 36 terminates in an outlet 30.

In a different embodiment (not shown), multiple openings are formed directly in the bottom wall 16 and multiple pipes are connected, each pipe being connected to a different opening without the presence of a valve.

Each pipe 37 terminates in a nozzle 38 with an outlet 30, as seen in Figures 3 and 4. The nozzle 38 is a curved nozzle with a horizontal inlet 39 and an outlet 30 through which the slurry exits, forming a flow with a component along the conveying direction 12.

2, the number of substrate sheets 8 is equal to the number of outlets 30. All substrate sheets are in contact with the surface 41 of the drum 4 at their second surface 1. The width 42 of each substrate sheet 8 is preferably equal to the width of a standard "small bobbin" (e.g., preferably about 10 millimeters to about 300 millimeters) used for further processing of the sheet 200. The width 42 of all substrate sheets 8 is preferably the same.

Furthermore, additional sensors (not shown) are preferably arranged on the substrate sheet 200 downstream of the outlet 30 to measure the weight per square centimeter and thickness of the homogenized tobacco sheet 200. The sensors may be, for example, nuclear measurement heads. There are preferably also additional sensors not shown in the drawings, such as sensors for locating and determining defects in the homogenized tobacco sheet, sensors for determining the moisture of the sheet 200, sensors for measuring the thickness of the sheet, sensors for checking the alignment of the sheets to avoid misaligned sheets and jams of the sheets when more than one sheet is formed, etc.

The function of the equipment 100 for forming a plurality of homogenized tobacco sheets 200 is as follows: A slurry 22, preferably formed by mixing and combining tobacco powder, water, and other ingredients, preferably with zero or low added fiber content, is transferred from a storage tank (also not shown) to an extruder 2, for example using an in-line mixer (not shown). The slurry reduces its water content in the extruder 2 and is extruded inside a tank 3. In the tank 3, a valve 36 is opened and the slurry reaches an outlet 30, with or without the need for a pump 31. A nozzle 38 delivers the slurry onto a fiber-containing substrate sheet 8, which is positioned in contact with a moving drum 4. The movement of the drum 4 causes a transition of the substrate sheet 8 along the conveying direction 12. Each nozzle 38 deposits a slurry onto a different substrate sheet 8. Thus, a plurality of homogenized tobacco sheets 200 are formed.

The thickness and basis weight of the sheet 200, controlled by the nucleon gauge immediately after slurry delivery, are preferably continuously monitored and feedback controlled using a slurry measurement device.

Claims (14)

1. A method for the manufacture of a sheet of alkaloid-containing material comprising the steps of:
providing a slurry comprising an alkaloid-containing material, an aerosol former and water;
extruding the slurry;
Collecting the extruded slurry in a tank having multiple outlets;
Providing two or more substrate sheets comprising fibers;
and dispensing the slurry from said plurality of outlets to form a plurality of strips of slurry onto said two or more substrate sheets comprising fibres to form two or more sheets of material containing an alkaloid. providing a slurry from the plurality of outlets;
10. The method of claim 1, comprising: o spraying the slurry onto at least one substrate sheet; or o depositing the slurry onto at least one substrate sheet. The method according to any one of claims 1 to 2, further comprising a step of adjusting the pressure or flow rate of the slurry supplied from at least one of the plurality of outlets. The method of claim 3, wherein the step of adjusting the pressure or the flow rate of the slurry delivered from at least one of the plurality of outlets comprises adjusting the pressure or the flow rate of the slurry delivered from at least one of the plurality of outlets independently from at least one of the other outlets of the plurality of outlets. The method of claims 1 to 4, further comprising reducing the amount of water in the slurry during extrusion. The method according to any one of claims 1 to 5, further comprising a step of directing the flow of slurry supplied from at least one of the plurality of outlets along the direction of movement of the base sheet using a component. assessing the thickness of at least one of the sheets of two or more materials containing the alkaloid;
〇 modifying the thickness of at least one of the two or more sheets of material containing an alkaloid if the evaluated thickness is outside a given range of values by compressing the at least one of the sheets of material containing an alkaloid. Providing a slurry comprising an alkaloid-containing material, an aerosol former, and water;
providing said material containing alkaloids to said slurry in an amount comprising about 40 percent to about 70 percent of the total weight of said slurry;
providing the water to the slurry in an amount comprising about 30 percent to about 55 percent of the total weight of the slurry;
8. The method of claim 1, comprising: providing a binder to the slurry in an amount between about 0 percent and about 1 percent of the total weight of the slurry; or providing the aerosol former to the slurry in an amount between about 1 percent and about 5 percent of the total weight of the slurry. providing a slurry comprising an alkaloid-containing material, an aerosol former, and water;
A method according to one or more of claims 1 to 8, comprising a step of grinding the alkaloid-containing material to a powder having a size comprised between about 8 micrometers and 200 micrometers. The method of any one or more of claims 1 to 9, comprising providing at least one of the two or more substrate sheets comprising fibers having an average fiber length of about 0.7 millimeters to about 2.5 millimeters. The method according to one or more of claims 1 to 10, comprising a step of homogenizing the extruded slurry collected in the tank. dispensing the slurry from the plurality of outlets to form a plurality of parallel strips of slurry;
providing a moving drum located below the outlets, the moving drum rotating about an axis;
Providing two or more bobbins of substrate sheet;
unwinding said two or more bobbins so as to obtain two or more substrate sheets comprising fibers;
placing the two or more substrate sheets comprising fibers in contact with the moving drum so as to move the two or more substrate sheets along a moving direction due to rotation of the moving drum;
The method according to one or more of the preceding claims, comprising: feeding slurry from the multiple outlets onto the two or more substrate sheets comprising fibers while moving the two or more substrate sheets comprising fibers along the moving direction by the moving drum. 1. A system for the production of sheets of two or more materials containing an alkaloid, comprising:
- two or more bobbins of a substrate sheet containing fibers;
- an installation for supplying a slurry to said two or more substrate sheets comprising fibres,
i. an extruder adapted to extrude the slurry;
ii. a tank adapted to contain the slurry, the tank having multiple outlets;
iii. An equipment comprising: a moving element adapted to move the two or more base sheets comprising fibers unwound from the two or more bobbins along a conveying direction and below the outlet such that a slurry is applied to the two or more base sheets. The system of claim 13, wherein the extruder is a screw extruder.