CN114828662A - Sheets of alkaloid containing material - Google Patents

Abstract

The present invention relates to a multi-layer sheet of alkaloid-containing material, the multi-layer sheet comprising: a first layer comprising a matrix sheet comprising fibers having a thickness of about 1 mm to an average fiber length of about 5 mm, the first layer defining a first surface and a second surface; a second layer comprising a mixture of: the powder of the alkaloid-containing material, the The powder has a size of about 8 microns to about 200 microns; #water; #binder; #aerosol former; the second layer is applied to the first surface of the base sheet, and wherein the The binder is included in an amount from about 0% to about 1% of the total weight of the multilayer sheet of alkaloid-containing material.

Description

Sheets of alkaloid-containing materials

The present invention relates to sheets of alkaloid-containing material, such as multilayer sheets or composite sheets.

In particular, the alkaloid-containing material may be a homogenized tobacco material, which is preferably used in aerosol-generating articles such as cigarettes or tobacco-containing "heat-not-burn" type products.

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

In a "heat not burn" aerosol-forming article, the aerosol-forming substrate is heated to a relatively low temperature to form the aerosol but prevent the tobacco material from burning.

Homogenized tobacco material is produced by mixing different components, including tobacco powder, to form a tobacco slurry. Furthermore, the pulp typically contains fibers such as cellulose fibers in addition to the fibers contained in the tobacco. The slurry is then stored in storage tanks before being sent via a suitable delivery system to a casting system where it enters a "cast box" to be cast on a moving conveyor belt and then into a dryer Medium dry.

There is a need for a method of obtaining an alkaloid-containing alternative material that can be used in heat-not-burn products.

In one aspect, the present invention relates to a multi-layer sheet of alkaloid-containing material comprising: a first layer comprising a matrix sheet comprising fibers, the fibers having a thickness of from about 0.7 mm to about 50 Average fiber length in mm. The first layer defines a first surface and a second surface. The multilayer sheet also includes a second layer comprising a mixture of: a powder of an alkaloid-containing material having a size of from about 8 microns to about 200 microns; water; a binder; and an aerosol forming agent. The second layer is applied to the first surface of the substrate sheet.

The present invention also relates to a sheet of alkaloid-containing composite material comprising: a matrix sheet comprising fibers, the matrix sheet having an average fiber length of about 0.7 millimeters to about 50 millimeters and defining a first surface and a second Second surface. The matrix sheet is impregnated with a mixture of: a powder of an alkaloid-containing material having a size of from about 8 microns to about 200 microns; water; a binder; and an aerosol former.

A multilayer sheet or sheet formed from a composite material is provided. Multilayer sheets or sheets formed from composite materials have relatively high tensile strengths when compared to known cast leaves. High tensile strength is provided by the matrix sheet with fibers that are relatively "long" compared to the fibers used in the casting blade. Furthermore, multilayer sheets or sheets formed from composite materials are relatively uniform. The slurry is applied to a fiber-containing matrix sheet to form a multilayer sheet or a sheet formed from an alkaloid-containing composite. It is not necessary to add large amounts of fibers to the slurry to obtain a multilayer sheet with relatively high tensile strength or a sheet formed from an alkaloid-containing composite, as it is already provided by the matrix sheet. Thus, the slurry can be very homogeneous in its composition (at least on its surface), and the resulting multilayer sheet or the sheet formed from the composite obtained when the slurry is applied to the matrix sheet is also homogeneous. The slurry can form a layer on the substrate sheet. The slurry can impregnate the matrix sheet. Better control over the composition of the multilayer sheet or sheet formed from the composite material can be achieved.

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

As used herein, the term "slurry" refers to a liquid, viscous or pasty material, which may include emulsions of various liquid, viscous or pasty materials. The slurry may contain a certain amount of solid particles, provided that the slurry still exhibits liquid, viscous or pasty behavior.

In the following, the term "upstream" or "downstream" is used to refer to the flow direction of the slurry.

As used herein, the term "movable support" means any means comprising a surface adapted to move in at least one longitudinal direction. The movable support can form a closed loop, providing uninterrupted conveyance in one direction. However, the movable support can also be moved in a reciprocating manner. The movable support may comprise a conveyor belt. The movable support may be substantially flat. The movable supports can exhibit structured or unstructured surfaces. The movable supports may comprise sheet-like movable and flexible straps. The straps may be made of metallic materials, including but not limited to steel, copper, iron alloys, and copper alloys, or may be made of rubber.

"Fiber-containing matrix sheet" means a sheet that is used as a matrix for pulp and formed in a fiber-containing material. The material from which the sheet is formed may include any type of fibers, such as cellulosic fibers. The sheet of material may be placed on a movable support or it may be self-supporting.

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

Alkaloids are a group of naturally occurring compounds that mainly contain basic nitrogen atoms. This group also includes some related compounds that are neutral or even weakly acidic. Some synthetic compounds with similar structures are also called alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids can also contain oxygen, sulfur, and more rarely, other elements such as chlorine, bromine and phosphorus.

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

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

The most commonly used forms of homogenized tobacco material are reconstituted tobacco sheets and cast leaves. Methods of forming sheets of homogenized tobacco material generally include the step of mixing tobacco powder and a binder to form a slurry. The slurry is then used to form tobacco sheets. For example, so-called casting leaves are produced by casting a viscous slurry onto a moving metal belt. Alternatively, reconstituted tobacco can be produced in a process similar to papermaking using slurries with low viscosity and high moisture content.

Sheet materials of tobacco may be referred to as reconstituted sheet materials and are formed using granulated tobacco or a granulated tobacco blend, a humectant, and an aqueous solvent to form a tobacco composition.

In addition to tobacco, homogenized tobacco sheets typically contain a binder such as guar gum. The homogenized tobacco sheet may also contain an aerosol former, such as glycerin.

The term "aerosol-forming substrate" refers to a substrate capable of releasing aerosol-forming volatile compounds. Typically, aerosol-forming substrates release volatile compounds when heated. The aerosol-forming substrate may comprise an alkaloid-containing material containing volatile alkaloid flavor compounds that will be released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may comprise a homogenized 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. Preferably, the aerosol generating device comprises an aerosolizer, such as a heater.

Multilayer sheets or sheets of alkaloid-containing composites can be used as aerosol-forming substrates for aerosol-generating devices. The sheet of alkaloid-containing material may comprise a homogenized tobacco sheet.

A multi-layer sheet or sheet of alkaloid-containing composite is formed starting from a matrix sheet on which the slurry is applied.

A matrix sheet comprising fibers is provided. The matrix sheet defines a first surface and a second surface. On the first surface, the slurry is applied. The slurry can form another layer, such as a second layer, on the first surface of the substrate sheet. Additionally, the slurry may substantially completely impregnate the matrix sheet. Additionally, the slurry may partially impregnate the matrix sheet such that the matrix sheet is partially impregnated and partially covered by the second material layer on the first surface.

A fiber-containing matrix sheet is generally a relatively "strong" sheet with a tensile strength such that it can be transported between rolls without requiring any other substrates with which it must come into contact. The tensile strength of the matrix sheet is preferably from about 0.1 N/(mm) ² to about 1 N/(mm) ² .

The matrix sheet can be made from various natural or synthetic materials, including cellulose, hemp, kenaf, bamboo pulp, cotton, silk, wood, or combinations thereof. The selection of materials is based on the expected mechanical properties of the final sheet including the alkaloid-containing material.

The fibers in the matrix sheet may or may not be woven. If not woven, the fibers may be oriented primarily in one direction. Alternatively, the fibers can be randomly oriented. If woven, various patterns can be used. The matrix sheet may comprise a fiber mat. The fibers may, for example, be randomly arranged, flattened into a sheet, or woven into a fabric. The matrix sheet may contain a binder to hold the fibers together. The binder can include methyl cellulose.

Preferably, the matrix sheet is a woven sheet. Woven sheets are sheets in which fibers are intertwined. Not all fibers need to be entangled, but some of them. Woven sheets allow to obtain uniform and relatively high mechanical strengths.

The fiber content in the matrix sheet is preferably below 50 g/(m) ² .

The matrix sheet preferably contains cellulose fibers. Cellulosic fibers that form sheets are known in the art and include, but are not limited to, softwood fibers, hardwood fibers, jute fibers, flax fibers, tobacco fibers, and combinations thereof. In addition to pulping, cellulosic fibers may be subjected to suitable processes such as refining, mechanical pulping, chemical pulping, bleaching, kraft pulping, and combinations thereof. Cellulosic fibers may include tobacco stem material, stems, or other tobacco plant material. Preferably, cellulosic fibers, such as wood fibers, contain low lignin content. Alternatively, fibers such as vegetable fibers may be used with the fibers described above or in substitutes comprising hemp and bamboo.

The fiber-containing matrix sheet includes fibers having an average fiber length of from about 0.7 millimeters to about 50 millimeters. More preferably, the fibers of the fiber-containing matrix sheet have an average fiber length of from about 1 millimeter to about 25 millimeters. More preferably, the fibers of the fiber-containing matrix sheet have an average fiber length of from about 1 millimeter to about 10 millimeters. More preferably, the fibers of the fiber-containing matrix sheet have an average fiber length of from about 1 millimeter to about 5 millimeters. Even more preferably, the fibers of the fiber-containing matrix sheet have an average fiber length of from about 1.2 millimeters to about 1.8 millimeters. Fibers with an average fiber length of 1 mm to 5 mm are the preferred compromise between the achieved tensile strength and the uniformity of the sheet,

The average length of the fibers refers to the true length of the fibers (whether they are crimped or kinked) as measured by the MORFI COMPACT commercialized by Techpap SAS. Average length is the mathematical mean of the measured lengths of fibers measured by MORFI COMPACT over N fibers, where N>5. MORFI COMPACT is a fiber analyzer that measures the length of a fiber based on its architecture and thus its actual unfolded length. If the measured object has a length of 200 microns to 10000 microns and its width is 5 microns to 75 microns, the measured objects are considered fibers. Fiber length is measured when deionized water is added to the fiber and Morfi software is used.

The matrix sheet defines first and second surfaces that oppose each other. The first surface or the second surface may be a substantially flat surface. The first surface or the second surface may be horizontal, ie parallel to the horizontal plane, or inclined. The first surface or the second surface may also be substantially vertical.

The slurry to be applied to the first surface of the substrate sheet had the following composition.

The slurry contains particles of alkaloid-containing material. The particles form a powder of the alkaloid-containing material. To obtain a powder, the alkaloid-containing material is ground into a powder. Preferably, the abrasive particles of the alkaloid-containing material have a size of less than 200 microns, preferably less than 180 microns, preferably less than 160 microns, preferably less than 140 microns, preferably less than 120 microns, preferably less than 100 microns, preferably less than 80 microns, preferably less than A size of 60 microns, preferably less than 40 microns. Preferably, the abrasive particles of the alkaloid-containing material have a size greater than 8 microns, preferably greater than 12 microns, preferably greater than 20 microns, preferably greater than 30 microns, preferably greater than 50 microns, preferably greater than 70 microns. Preferably, the step of grinding the alkaloid-containing material to a powder comprises grinding the alkaloid-containing material to a powder having a size of about 8 microns to 200 microns. More preferably, the step of grinding the alkaloid-containing material into a powder comprises grinding the alkaloid-containing material to a size of about 10 microns to 150 microns. Even more preferably, the step of grinding the alkaloid-containing material to a powder comprises grinding the alkaloid-containing material to a size of about 15 to 120 microns.

For the size of the particles of the alkaloid-containing material, the Dv95 size is meant. Each of the above listed values indicates the Dv95 of the particle size. The "v" in Dv95 means volume distribution is considered. Using a volume distribution introduces the concept of an equivalent sphere. An equivalent sphere is one that is equal to the real particle in the property we are measuring. So, for the light scattering method, it is a sphere that will produce the same scattering intensity as a real particle. This is basically a sphere of particles with the same volume. Furthermore, "95" in Dv95 means that ninety-five percent of the distribution has diameters of the smaller particle size and five percent of the larger particle size. Thus, particle size is a size according to a volume distribution, wherein 95% of the particles have a diameter (of a corresponding sphere of particles of substantially the same volume) that is smaller than the stated value. A particle size of 60 microns means that 95% of the particles have a diameter of less than 60 microns, where the diameter is the diameter of a sphere having a volume corresponding to the particle.

The Dv95 size of the particles was measured using a Horiba LA 950 or LA 960 particle size distribution analyzer. The HORIBA LA-960 particle size analyzer measures the size distribution using laser diffraction. This technique uses first principles to calculate size using light that scatters from the particle (edge diffraction) and passes through the particle (double scattering refraction). LA-960 incorporates Mie scattering theory.

The size of the powder need not be "extremely small" due to the fact that the slurry preferably contains no or only very small amounts of cellulose fibers other than those already contained in the alkaloid-containing material. If fibers are present in the slurry, the fibers act as "glue" for the particles. Therefore, in order to have a uniform sheet, the particles are kept small. In the present invention, the slurry itself does not form a sheet, but is applied to the substrate layer. The slurry itself is not required to produce a layer with relatively high tensile strength. Therefore, the size of the powder can be larger than in the case of a slurry formed by adding fibers.

The powder of the alkaloid-containing material can be, for example, a tobacco powder blend. Preferably, the tobacco powder blend contains the majority of the tobacco present in the slurry. As such, the tobacco powder blend is the source of most of the tobacco in the homogenized tobacco material. Thus, the tobacco powder blend defines the flavor of the final product (eg, an aerosol produced by heating homogenized tobacco material).

The amount of powder of the alkaloid-containing material in the slurry is preferably from about 40% to about 70% of the total mass of the slurry (ie, the mass of the slurry including water). Preferably, the alkaloid-containing material is preferably in powder form. More preferably, the amount of alkaloid-containing material in the slurry is preferably from about 40% to about 50% of the total mass of the slurry (ie, the mass of the slurry including water).

A binder is preferably added to the slurry to enhance the tensile properties of the multilayer sheet or sheet of composite material.

The amount of binder present in the slurry may range from about 0% to about 1% of the total mass of the slurry (ie, the mass of the slurry including water). More preferably, the binder is present in the slurry in an amount from about 0% to about 0.5% 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 substantial absorption of the slurry by the matrix sheet is desired, less binder may be used to improve absorption. Higher amounts of binder may be used if it is preferred that the slurry be coated on the substrate sheet. The amount of binder can change the viscosity of the paste. Higher amounts of binder can result in higher slurry viscosity.

The binder used in the slurry can be any of the gums or pectins described herein. The binder ensures that the alkaloid powder remains substantially dispersed throughout the sheet of alkaloid-containing material. Although any binder can be used, preferred binders are natural pectins such as fruit, citrus or tobacco pectins; guar gums such as hydroxyethyl guar and hydroxypropyl guar; locust bean gum , such as hydroxyethyl and hydroxypropyl locust bean gum; alginates; starches, such as modified or derivatized starches; celluloses, such as methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, and carboxymethyl base cellulose; tamarind gum; glucan; pullalon; konjac flour; xanthan gum, etc. A particularly preferred binder for use in the present invention is guar gum.

If the slurry impregnates the matrix sheet, the amount of binder varies depending on which part of the sheet is considered, eg it is greatest at the surface where the slurry has been deposited. Therefore, the maximum value is 0% to 1%.

Preferably an aerosol former is added to the slurry to facilitate aerosol formation.

Suitable aerosol formers for inclusion in slurries for sheets of alkaloid-containing material are 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, and glycerol; esters of polyhydric alcohols, such as monoacetin, diacetin, or triacetin; and aliphatic esters of mono-, di- or polycarboxylic acids, such as ten Dioxanedioic acid dimethyl ester and tetradecanedioic acid dimethyl ester.

Examples of preferred aerosol formers are glycerol and propylene glycol.

The slurry may have an aerosol former content of about 1% to about 5% of the total mass of the slurry (ie, the mass of the slurry including water). Preferably, it constitutes 1% to 3% of the total mass of the slurry, which corresponds to an amount of the aerosol former of about 2.9% to about 8.5% by dry weight of the slurry.

Water is also preferably present in the slurry to achieve a certain viscosity and moisture for applying the slurry to the substrate sheet. The amount of water is preferably about 30% to 55% of the total mass of the slurry (ie the mass of the slurry including water). More preferably, the amount of water is from about 45% to about 55% of the total mass of the slurry, ie, the mass of the slurry including water.

The alkaloid-containing material, preferably in powder form, may contain cellulose. Preferably, however, no added cellulosic fibers are present in the pulp, ie no more fibers are added to the pulp than are already contained in the alkaloid-containing material. Therefore, the amount of fibers (ie in addition to those already contained in the alkaloid-containing material) added to the pulp is preferably less than 0.5% of the total mass of the pulp, ie the mass of the pulp including water. More preferably, the added fibers are present in an amount less than about 0.1% of the total mass of the pulp.

A slurry is formed at a given location. The slurry can then be stored. The slurry may, for example, be stored and formed in the same location, such as in the same storage tank, or stored and formed in two different locations, such as in two different storage tanks. The tanks used are preferably known in the art. Additionally, the slurry can be formed or stored in a single storage tank, or in multiple storage tanks. Preferably, a mixer is present in the storage tank to homogenize the slurry.

Preferably, the slurry is applied to the first surface of the matrix sheet. In application, the slurry may form a strand of slurry on the fiber-containing matrix sheet.

The slurry need not be applied to the entire first surface. The slurry may be applied to only a portion of the first surface, eg, a central portion of the first surface.

The slurry in contact with the matrix sheet can be completely absorbed or adsorbed by the matrix sheet. The slurry may form a layer on the first surface of the substrate sheet, referred to as the second layer. The slurry may be partially absorbed or adsorbed by the substrate sheet and partially coat the first surface of the substrate sheet.

Preferably, the application of the slurry can form a second layer on the substrate sheet. Basically, a coating of slurry is formed on the first surface of the substrate sheet.

Application of the slurry The matrix sheet can be impregnated with the slurry.

The slurry can be minimally, partially or largely absorbed or adsorbed by the matrix sheet. The pulp absorption or adsorption depends on the composition of the matrix sheet or the composition of the pulp, or both the composition of the matrix sheet and the composition of the pulp. For example, slurry absorption or adsorption depends on the amount of water or binder contained in the slurry. If the slurry is only minimally or partially absorbed by the matrix sheet, a second layer will be formed on the surface of the matrix sheet to which the slurry is applied and a multilayer sheet will be formed.

If a sorption process occurs - in which the slurry is absorbed or adsorbed by the matrix sheet - the matrix sheet will be impregnated with the slurry. The slurry can be completely absorbed by the matrix sheet. The slurry can also both form a coating and impregnate the matrix sheet.

Sorption is a physical and chemical process by which one substance attaches to another. Sorption is specific to: absorption, in which a substance in one state is incorporated into a substance in a different state, and this liquid slurry is absorbed by a solid matrix sheet; or adsorption, in which ions and molecules physically adhere or bond on the surface of the other phase.

The resulting sheets formed from the matrix sheet and the slurry applied to the first surface may have different compositions in cross-sections taken perpendicular to the first surface of the matrix sheet. At the second surface, the lowest concentration of slurry may be present. At the first surface, the highest concentration of slurry may be present. The combination of the material of the matrix sheet and the slurry may be present in different concentrations between the first surface and the second surface.

The slurry can be applied to both the first surface and the second surface. The composition of the sheet of alkaloid-containing material may be symmetrical. The fiber concentration per unit volume of the sheet of alkaloid-containing material may be highest at the center of the sheet of alkaloid-containing material and lowest at the first and second surfaces.

The combination of the matrix sheet and the slurry provided on its first surface forms a multilayer sheet of alkaloid-containing material or a sheet of alkaloid-containing composite material.

In addition to the matrix sheet and slurry, other elements may be combined to form a multilayer sheet of alkaloid-containing material or a sheet of alkaloid-containing composite material. The matrix sheet itself may be a multilayer sheet. Matrix sheets may include flavor sheets, alkaloid (eg, nicotine) containing material sheets, and the like.

Forming a multi-layer sheet of alkaloid-containing material or a sheet of alkaloid-containing composite material by feeding a slurry onto an already formed fiber-containing matrix sheet allows substantially no added fibers to be used in the slurry, Or use a very limited amount of added fiber. Fibers are often added to prior art cast sheet slurries to increase the tensile strength of the sheet, thereby acting as reinforcing agents.

However, the presence of the matrix sheet on which the slurry is fed will provide sufficient tensile strength to the resulting sheet of alkaloid-containing material. Addition of cellulosic fibers to the pulp can be avoided.

In fiber-added slurries, relatively large amounts of water may be required, as fiber pulping requires water. Additionally, 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 alkaloid-containing material. The conveyor belt on which the slurry is cast also plays an important role in this "high water content" process: any defects in the conveyor belt can be transferred to the casting sheet, so a high-quality conveyor belt is usually required. Removing the added fibers from the pulp allows reducing the amount of water required to homogenize the pulp. Good homogenization still requires a certain amount of water. This relatively "dense" slurry is suitable for application to fiber-containing matrix sheets.

Less drying time or less drying power is required to dry a multi-layer sheet of alkaloid-containing material or a sheet of alkaloid-containing composite material according to the present invention. The substrate sheet is preferably already dry when it is wound into a spool. The substrate sheet may be wetted, eg, sprayed with water, prior to contacting the slurry. Wetting is performed to facilitate penetration of the slurry into the matrix sheet. The resulting multilayer sheet of alkaloid-containing material or sheet of alkaloid-containing composite material is only "partially wetted" and the drying time or amount of energy required for drying is relatively low. When used as an aerosol-forming substrate, less "intensive" drying allows for better control of the flavor of the aerosol produced by the multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material. During the drying process, alkaloids, flavors, or other volatiles may evaporate and their concentration may be reduced in the multilayer sheet of alkaloid-containing material or in the sheet of alkaloid-containing composite material. Minimizing drying when alkaloids are present helps control aerosol properties.

The fact that a fiber-containing matrix sheet is provided allows to obtain a multilayer sheet of alkaloid-containing material or a sheet of alkaloid-containing composite material with sufficient tensile strength, which strength is imparted by the fibers to allow in downstream manufacturing steps Robust processing. The length or configuration of the fibers is not constrained by having a homogeneous material containing alkaloids. The tensile strength is provided by the matrix sheet, while the properties of the aerosol are imparted by the slurry applied to the matrix sheet. Both tensile strength and aerosol properties can be independently optimized.

Preferably, the first layer is partially impregnated by the second layer. In a multilayer sheet, there may be no "sharp" transitions between the first and second layers. The slurry forming the second layer may be partially absorbed by the second layer. Depending on the composition of the matrix sheet or the slurry, or both the matrix sheet and the slurry, eg depending on the amount of water or binder contained in the slurry, the slurry may be minimally , partially or mostly absorbed by the matrix sheet. If the slurry is only minimally or partially absorbed by the matrix sheet, a slurry layer, ie a second layer, will be formed on the surface of the matrix sheet to which the slurry is applied. A coating of slurry can then be formed on the surface of the substrate sheet. On the other hand, if a sorption process occurs - in which the slurry is absorbed or adsorbed by the matrix sheet - the matrix sheet will be impregnated with the slurry. The slurry can be completely absorbed by the matrix sheet. The slurry can also both form the second coating and impregnate the matrix sheet.

Preferably, the multilayer sheet of alkaloid-containing material comprises a third layer comprising a mixture of: a powder of alkaloid-containing material having a size of about 8 microns to about 200 microns; water; a binder; an aerosol former; the third layer is applied to the second surface of the base sheet. The multilayer sheet may be symmetrical, with the second and third layers applied to both the first and second surfaces of the matrix sheet. The second layer may be the same as the second layer. When the second layer is different from the third layer, the multilayer sheet can be asymmetrical. For example, the thickness of the second layer may be different from the thickness of the third layer.

Preferably, the multi-layer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material comprises powder of alkaloid-containing material in an amount of the From about 40% to about 80% of the total weight of the sheet of composite material. The multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material contains high levels of alkaloid-containing material. This amount is obtained for a "dry" sheet, ie, a sheet having a moisture content of from about 7% to about 15%.

In the present invention, the pulp is preferably formed from a suitable blend of tobacco leaves and stems of different tobacco types. Preferably, more than one tobacco type is blended together. For example, at least two different tobacco types are blended together. The term "tobacco type" means one of different tobacco varieties. For the purposes of the present invention, these different tobacco types can be distinguished into three main groups: flue-cured, sun-cured, and flavored tobacco. The distinction between these three groups is based on the tobacco curing process performed prior to further processing into tobacco products.

Flue-cured tobacco is a tobacco with usually large pale leaves. Throughout this specification, the term "flue-cured tobacco" is used for tobacco that has been smoked. Examples of flue-cured tobacco are Chinese flue-cured tobacco, Brazilian flue-cured tobacco, American flue-cured tobacco, such as Virginia tobacco, Indian flue-cured tobacco, Tanzania flue-cured tobacco or other African flue-cured tobacco. Flue-cured tobacco is characterized by a high sugar-to-nitrogen ratio. From a sensory point of view, flue-cured tobacco is the type of tobacco that is accompanied by a pungent and refreshing feeling after curing. According to the present invention, flue-cured tobacco is a tobacco having a reducing sugar content of about 2.5% to about 20% by dry leaf weight and a total ammonia content of less than about 0.12% by dry leaf weight. Reducing sugars include, for example, glucose or fructose. Total ammonia includes, for example, ammonia and ammonia salts.

Sun-cured tobacco is tobacco with usually large dark leaves. Throughout this specification, the term "cured tobacco" is used for tobacco that has been air-dried. In addition, sun-cured tobacco can ferment. Tobacco used primarily for chewing, snuff, cigars, and pipe blends is also included in this category. From a sensory point of view, sun-cured tobacco is a type of tobacco that has a dark cigar-like feel with a smoky flavor after curing. Sun-cured tobacco is characterized by a low sugar-to-nitrogen ratio. Examples of sun-cured tobacco are Malawi burley or other African burley, dark roasted Brazil Galpao, sun-cured or cured Indonesian Kasturi. According to the present invention, sun-cured tobacco is tobacco having a reducing sugar content of less than about 5% by dry weight of the tobacco leaf and a total ammonia content of up to about 0.5% by dry weight of the tobacco leaf.

Flavored tobacco is a tobacco that often has small, pale leaves. Throughout this specification, the term "flavor tobacco" is used for other tobaccos with high aroma content, eg, high content of essential oils. From a sensory point of view, oriental tobacco is the type of tobacco that is accompanied by a pungent and aromatic sensation after curing. Examples of flavored tobaccos are Greek Oriental, Oriental Turkey, Semi-Oriental tobacco and cured American Burley such as Perique, Rustica, American Burley or Meriland.

In addition, the blend may include so-called filler tobacco. Filler tobacco is not a specific tobacco type, but it includes tobacco types that are primarily used to complement other tobacco types used in blends and do not impart specific characteristic aromas into the final product. Examples of filler tobaccos are stems, midribs or stems of other tobacco types. A specific example may be the flue-treated stem of a flue-treated Brazilian lower stem.

Within each type of tobacco, the tobacco leaves are further graded, eg, by origin, location in the plant, color, surface texture, size and shape. Tobacco leaves of these and other characteristics are used to form tobacco blends. Tobacco blends are mixtures of tobacco belonging to the same or different types, such that the tobacco blend has specific characteristics of agglomeration. This characteristic may be, for example, a unique taste or a specific aerosol composition upon heating or burning. The blend includes specific tobacco types and grades in given proportions of one relative to the other.

Different grades within the same tobacco type can be cross-blended to reduce variability in the components of each blend. According to the present invention, different tobacco grades are selected in order to obtain a desired blend with predetermined specific characteristics. For example, the blend may homogenize the tobacco material with target values of reducing sugars, total ammonia, and total alkaloids on a dry weight basis. Total alkaloids are, for example, nicotine and minor alkaloids including nornicotine, anatabine, neonicotine and myosmine.

For example, flue-cured tobacco may include grade A tobacco, grade B tobacco, and grade C tobacco. Grade A flue-cured tobacco has slightly different chemical characteristics than Grade B and C flue-cured tobacco. Flavored tobaccos may include D-grade tobaccos and E-grade tobaccos, where D-grade flavored tobaccos have slightly different chemical characteristics than E-grade flavored tobaccos. To illustrate, a possible target value for a tobacco blend may be, for example, a reducing sugar content of about 10% by dry weight of the total tobacco blend. To achieve the selected target value, 70% flue-cured tobacco and 30% flavored tobacco can be selected to form a tobacco blend. 70% flue-cured tobacco was chosen among grade A tobacco, grade B tobacco and grade C tobacco, and 30% oriental tobacco was chosen among grade D tobacco and grade E tobacco. The amount of Class A, B, C, D, E tobacco included in the blend depends on the chemical composition of each of the Class A, B, C, D, E tobaccos in order to meet the tobacco blend goals value.

Various tobacco types have different chemical characteristics. More than 300 chemical constituents are believed to be present in tobacco leaves. Within the same type of tobacco, different grades can also have differences in chemical composition. The chemical composition of tobacco can be influenced by genetics, agricultural practices, soil type and nutrients, weather conditions, plant diseases, leaf position, and collection and drying procedures.

Preferably, the multi-layer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material comprises water in an amount of From about 7% to about 15% of the total weight.

Preferably, the multi-layer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material comprises a binder in an amount that accounts for the amount of the multi-layer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material about 0% to about 1% of the total weight of the material. More preferably, the binder is present in the slurry in an amount ranging from about 0% to about 0.5% of the total mass of the slurry. The amount of binder may depend on the desired properties of the multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material. If substantial absorption of the slurry by the matrix sheet is desired, less binder may be used to improve absorption. Higher amounts of binder may be used if a slurry layer on the matrix sheet is preferred. The amount of binder can change the viscosity of the paste. Higher amounts of binder can result in higher slurry viscosity.

Preferably, the multi-layer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite comprises an aerosol-forming agent in an amount that accounts for the From about 2.9% to about 8.5% of the total weight of the sheet.

Multilayer sheet of alkaloid-containing material or sheet of alkaloid-containing composite material containing fibers other than fibers of alkaloid-containing material in an amount that accounts for the multi-layer sheet of alkaloid-containing material or alkaloid-containing material about 2% to about 5% of the total weight of the sheet of composite material. The fibers are concentrated in the matrix sheet and very few fibers (other than those contained in the alkaloid-containing material) are present in the second layer.

The multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite has a thickness of from about 150 microns to about 400 microns, more preferably the sheets have a thickness of from about 180 microns to about 300 microns, even more preferably About 180 microns to 250 microns.

Preferably, the matrix sheet has a thickness of 175 microns to about 250 microns. The thickness of the matrix sheet is preferably selected such that the final thickness when the slurry is applied to one or both of its surfaces is a thickness that is preferred for further processing of the sheet, such as crimping and gathering into strands.

The multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite preferably has a width of about 100 millimeters to about 2500 millimeters. The width of the multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material is chosen depending on the size of the spool to be obtained. Preferably, after the multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material is formed, it is dried. Preferably, after drying, the multilayer sheet of alkaloid-containing material or the sheet of alkaloid-containing composite material is wound into a spool. The spool may be a "master spool", which is then cut into smaller spools, or already a spool for further processing of sheets of alkaloid-containing material.

Preferably, the powder of the alkaloid-containing material comprises tobacco powder. Preferably, the powder is a tobacco powder blend.

Preferably, the fibre-containing matrix sheet comprises cellulosic fibres. More preferably, the fibre-containing matrix sheet comprises fibres derived from hemp, kenaf, bamboo, wood, cotton or silk.

The present invention may also relate to an aerosol-generating article comprising a multilayer sheet of alkaloid-containing material or part of a sheet of alkaloid-containing composite material according to the present invention. Aerosol-forming articles according to the present invention may encompass articles in which the alkaloid-containing material is heated to form an aerosol rather than burn.

The aerosol-forming article according to the present invention may be an entire assembled aerosol-forming article or an aerosol-forming article part in combination with one or more other components to provide an assembled article for generating an aerosol, such as that of a heated smoking device Consumables.

An aerosol-forming article may be one that generates an aerosol that can be inhaled directly into the user's lungs through the user's mouth. Aerosol-forming articles may resemble conventional smoking articles, such as cigarettes, and may include tobacco. Aerosol-forming articles may be disposable. Alternatively, the aerosol-forming article may be partially reusable and include a refillable or replaceable aerosol-forming substrate.

In preferred embodiments, the shape of the aerosol-forming article may be substantially cylindrical. The aerosol-forming article can be substantially elongated. The aerosol-forming article may have a length and a perimeter that is substantially perpendicular to the length. The aerosol-forming article may have an overall length of about 30 millimeters to about 100 millimeters. The aerosol-forming article can have an outer diameter of about 5 millimeters to about 12 millimeters.

In all aspects of the invention, preferably, the sheet comprising the alkaloid-containing material is a homogenized tobacco sheet, wherein the alkaloid-containing material is nicotine-containing tobacco.

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

- Figure 1 shows a flow chart of the method for producing a sheet of homogenized tobacco material according to the invention;

- Figure 2 shows an enlarged view of one of the steps of the method of Figure 1;

- Figure 3 shows a schematic perspective view of a first embodiment of an apparatus for producing sheets of alkaloid-containing material according to the invention;

- Figure 4 shows a schematic cross-sectional side view of a second embodiment of the apparatus for producing sheets of alkaloid-containing material according to the invention;

- Figure 5 shows a schematic cross-sectional side view of a third embodiment of the apparatus for producing sheets of alkaloid-containing material according to the invention;

- Figure 6 shows a schematic cross-sectional side view of a fourth embodiment of the apparatus for producing sheets of alkaloid-containing material according to the invention;

- Figure 7 shows a graph presenting the composition of a cross-section of a homogenized tobacco sheet produced with the method of the invention;

- Figure 8 shows a schematic diagram of a side view of a multilayer sheet according to the invention; and

- Figure 9 shows a schematic diagram of a side view of a composite sheet according to the invention.

Referring first to Figure 1, a method of producing a sheet 200 of alkaloid-containing material is shown. In the embodiment shown, the sheet of alkaloid-containing material 200 is a homogenized tobacco sheet and the alkaloid-containing material is tobacco.

The first step of the method of the present invention is to select the tobacco type and tobacco grade 100 to be used in the tobacco blend used to produce the homogenized tobacco material. Tobacco types and tobacco grades used in the method of the present invention are, for example, flue-cured, sun-cured, flavored, and filler tobaccos.

The selected tobacco type and tobacco grade intended to be produced for the homogenized tobacco material is processed according to the following steps of the method of the present invention.

The method includes a further step 101 of laying the selected tobacco. This step may include checking tobacco integrity, such as grade and quantity, which may be verified, for example, by a barcode reader for product tracking and traceability. After harvesting and drying, tobacco leaves are assigned grades that describe, for example, stem position, quality and color.

Additionally, the laying step 101 may also include unboxing or unboxing of the tobacco box if the tobacco is being shipped to a manufacturing site that produces homogenized tobacco material. Next, the unboxed tobacco is preferably fed to a weighing station for weighing.

Furthermore, if desired, the tobacco laying step 101 may include severing the bales, since tobacco leaves are usually compressed into bales and shipped in shipping boxes.

The following steps were performed for each tobacco type, as detailed below. These steps can then be performed in stages so that only one production line is required. Alternatively, different tobacco types can be processed in separate production lines. This can be advantageous when some tobacco types have different processing steps. For example, in conventional primary tobacco processing, flue-cured and sun-cured tobacco are at least partially processed in separate processes, as sun-cured tobacco often receives additional casing. However, according to the present invention, preferably, the blended tobacco powder is not flavored prior to forming the homogenized tobacco web.

Additionally, the method may include the step 102 of grinding the tobacco leaves. The grinding step 102 may be a single grinding step or a dual grinding step in which the tobacco is first coarsely ground and then finely ground.

Preferably, after the grinding step 102, a step of removing non-tobacco material from the powder (not depicted in Figure 1) is performed. This removal step can be performed before grinding. It may be easier to remove the non-tobacco material before grinding because the non-tobacco material can be more easily identified and removed than after grinding.

Preferably, after the grinding step 102, the tobacco particles are conveyed to the blending step 103, eg by pneumatic transfer.

In a blending step 103, all ground tobacco particles of the different tobacco types selected for the tobacco blend are blended. The blending step 103 is thus a single step for all selected tobacco types. This means that after the blending step, only a single production line is required for all the different tobacco types. In Figure 2, a blend of four coarsely ground tobacco particles of four different tobacco types selected for tobacco blends, schematically indicated by boxes 1, 2, 3 and 4, respectively, is presented .

In the blending step 103, the blending of the various tobacco types is preferably carried out in pellet form. Preferably, the step of measuring and controlling one or more properties of the tobacco blend is performed.

Alternatively, step 102 follows a blending step 103 in which the various tobacco types are blended together to form the desired blend. The process can be faster if done after the blending step.

It should be understood that each tobacco type may itself be a sub-blend, in other words, a "flue-cured tobacco type" may be, for example, a blend of different grades of Virginia tobacco and Brazilian flue-cured tobacco.

The tobacco powder thus obtained can be used immediately to form a tobacco slurry. Alternatively, a further step (not shown) of storing the tobacco powder, eg in a suitable container, can be inserted.

The tobacco powder from the fines blending step 103 is used in the subsequent slurry preparation step 104 . The slurry preparation step 104 preferably includes adding together the aerosol former, binder and ground tobacco powder in a slurry mixing tank. More preferably, this step further comprises processing the slurry with a high shear mixer to ensure the homogeneity and homogeneity of the slurry.

Preferably, the slurry preparation step 104 also includes the step of adding water, wherein water is added to the slurry to obtain the desired viscosity and moisture.

The composition of the slurry after step 104 is as follows:

Water: 30%-55%

Tobacco powder: 40%-70%

Binder: 0%-1%

Aerosol former: 1%-5%

Added fiber: less than 0.5%

To form the homogenized tobacco sheet 200, the slurry formed according to step 104 is preferably cast in a casting or applying step 105. Preferably, this casting step 105 includes delivering the slurry to a casting station and applying the slurry on the substrate sheet 11 (shown in Figures 3-6).

The homogenized cast sheet 200 is then dried in a drying step 106, which includes uniform and gentle drying of the cast web. Preferably, the drying step includes monitoring the casting leaf temperature of each drying zone to ensure a gentle drying profile for each drying zone.

Referring now to FIG. 3 , a first embodiment of an apparatus for producing a sheet 200 of homogenized tobacco according to the present invention is presented and indicated with reference numeral 10 .

Preferably, the apparatus 10 is adapted to produce a plurality of sheets 200 of homogenized tobacco material.

The apparatus 10 for producing a sheet of homogenized tobacco material comprises an extruder 5 , a tank 6 located at the outlet 20 of the extruder 5 and a moving drum 7 located below the tank 6 .

The extruder 5 comprises an inlet 21 for introducing a slurry 22 (indicated by arrows in FIG. 3 ) to form a sheet of homogenized tobacco material, a screw 23 for extruding the slurry 22 and an outlet 20 . The slurry 22 is pushed by the screw 23 from the inlet 21 to the outlet 20 (see again arrow 22 in Figure 3). The screw 23 that pushes the slurry 22 can be rotated by a motor 24, which is schematically depicted as a rectangle in FIG. 3 .

The slurry 22 reaches the extruder 5 from various storage tanks or silos (not shown in the figures). The slurry 22 contains tobacco powder, water, a binder and an aerosol former. Preferably, the binder is guar gum. Preferably, the aerosol former is glycerol. Preferably, no more fibers are added to the slurry. The slurry is formed as described in step 104 .

The slurry 22 reaches the tank 6 from the extruder 5 . From the above composition, about 5% of the water was removed from the slurry by an extrusion process.

Tank 6 includes a number of outlets, all indicated at 30 . Tank 6 may have any geometric shape, and in the depicted embodiment is essentially a basin. Tank 6 includes side walls 32 and also includes bottom wall 33 . A mixer 34 (indicated by arrows in FIG. 3 ) may be present within the tank 6 to agitate and mix the slurry 22 .

In addition, a sensor 50 is present in the tank 6 to measure the vertical level of the slurry 22 . Preferably, there is feedback between the sensor 50 and the extruder 5 so that the slurry in the tank 6 is maintained at a substantially constant level.

The moving drum 7 is located below the outlet 30 . The moving drum 7 is adapted to rotate about its axis 77 in the direction of rotation 8 indicated by the arrows in FIG. 3 . The moving drum 7 defines an outer cylindrical surface 41 .

Furthermore, the device 10 includes a plurality of spools 9 (a single spool is depicted in Figure 3). Each spool 9 of the plurality of spools is made from a roll of a matrix sheet 11 , such as a cellulosic fiber sheet. The spool is unwound and the free part of the sheet 11 unwound from the spool 9 is positioned in contact with the moving drum 7 . The matrix sheet 11 includes a first surface 12 and a second surface 13 that are opposed to each other. The second surface 13 is preferably in contact with the cylindrical surface 41 of the moving drum 7 . The first surface 12 faces at least one of the plurality of outlets 30 . The rotation of the moving drum 7 causes the plurality of substrate sheets 11 to move in a common conveying direction indicated by arrow 14 in FIG. 3 . The spool 9 is thus continuously unwound under the rotation of the drum 7 .

Each substrate sheet 11 of the plurality of substrate sheets is in contact with the surface 41 of the moving drum 7 and is free-standing downstream of the drum 7 in the conveying direction, ie the first surface 12 and the second surface 13 are not supported by any elements . Another roller or roller (not visible in the figures) can further pull the plurality of sheets 11 in the conveying direction 14 .

The slurry 22 is supplied to the plurality of substrate sheets 11 from the outlet 30 . Preferably, each outlet 30 of the plurality of outlets feeds the slurry 22 to a single matrix sheet 11 of the plurality of sheets. The slurry is delivered from the outlet 30 by gravity or by applying pressure, for example by means of a pump (not shown in the figures). Preferably, the pump includes flow rate control means (not visible in the drawings) to control the amount of slurry delivered to the matrix sheet 11 .

When the matrix sheet 11 is fed with the slurry 22 it becomes a homogenized tobacco sheet 200 . The slurry may be partially or completely absorbed by the matrix sheet 11 . Most slurries can coat the substrate sheet 11 , especially the first surface 12 .

The second surface 13 may also be supplied with slurry 22 .

Each outlet 30 preferably terminates in a nozzle 38 where the outlet 30 exists.

Furthermore, preferably further sensors (not shown) are arranged at 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 sensor can be, for example, a nuclear measurement head. There are also preferably additional sensors not shown in the figures, such as sensors for locating and determining the location of defects in the homogenized tobacco sheet. A sensor to determine the moisture of the sheet 200 can be added. There may be sensors to measure the thickness of the sheet. Sensors can be added to check the alignment of the sheets to avoid misalignment and jamming of sheets if more than a single sheet is formed.

The operation of the apparatus 10 for forming the plurality of homogenized tobacco sheets 200 is as follows. The slurry 22 formed, preferably without or with The storage tank (also not shown) is transferred to the extruder 5 . The slurry reduces its water content at extruder 5 and is extruded into tank 6 . In tank 6, the slurry reaches outlet 30, with or without a pump. The nozzles 38 feed the slurry onto the fibre-containing matrix sheet 11 which is positioned in contact with the moving drum 7 . The movement of the drum 7 causes the substrate sheet 11 to be displaced in the conveying direction 14 . Each nozzle 38 deposits the slurry on a different substrate sheet 11 . A plurality of homogenized tobacco sheets 200 are thus formed.

The thickness and grammage per square meter of the sheet 200 controlled by the nucleometer immediately after the slurry feed is preferably continuously monitored and feedback controlled using a slurry measuring device.

In Figure 4, a second embodiment of an apparatus 110 for producing a homogenized tobacco sheet 200 is shown. Apparatus 110 includes casting box 42 containing slurry 22 and matrix sheet 11, wherein casting rolls 45 associated with casting box 42 cast slurry 22 contained in casting box 42 to matrix sheet 11 above to form a cast sheet 200 of homogenized tobacco material. Slurry 22 is prepared as in step 104 above.

The substrate sheet 11 is wound around moving rolls (only roll 52 is shown) and positioned above the casting box 42 . The substrate sheet 11 defines a first surface 12 and a second surface 13 and is moved under the action of moving rollers 52 in the conveying direction 14 indicated by the arrow in FIG. 4 .

The casting box 42 includes side walls including a first wall 43 and a second opposing wall 44 . The casting box 42 is generally defined by four side walls, namely, a first wall 43 and a second opposing wall 44 and a third and fourth opposing wall connecting the first wall 43 and the second opposing wall 44 (Fig. not shown).

Additionally, the casting box 42 includes a bottom wall 46 . It also includes a hole 47, which in this case coincides with the top of the casting box. The holes 47 are positioned adjacent to the matrix sheet 11 .

The incoming slurry 22 is introduced into the casting box 42 from an inlet (not visible), in particular, for example, the end of a tube connected to one of the side walls of the casting box.

The slurry 22 from the buffer tank (not shown in the drawings) is transferred into the casting box 42 by means of a pump (not shown in the drawings). Preferably, the pump includes a flow rate control device (not visible in the drawings) to control the amount of slurry 22 introduced into the casting box 42 . Advantageously, the pump is designed to ensure that the slurry transfer time is kept to a necessary minimum.

The amount of slurry 22 in casting box 42 has a predetermined level, which preferably remains substantially constant or within a given range. In order to maintain the amount of slurry 22 at substantially the same level, a pump will control the flow of slurry 22 to casting box 42 .

A casting roll 45 is associated with the casting box 42 for casting the slurry. The casting roll 45 has a major dimension, namely its longitudinal width. The casting roll defines a first axis of rotation 48 (indicated by a cross in Figure 4) corresponding to its longitudinal direction. Preferably, the first axis of rotation 48 is horizontal, more preferably perpendicular to the casting direction 17 .

The casting rolls 45 are preferably rotatably attached to the two opposite side walls of the casting box 42 by means of their ends. Furthermore, the casting roll 45 partially protrudes from the hole 47 and faces the substrate sheet 11 (see Fig. 4 for details).

There may be a gap between the casting roll 45 and the substrate sheet 11, the size of which determines, inter alia, the thickness of the casting web 200 of homogenized tobacco material.

The slurry 22 is cast on the substrate sheet 11 by casting rolls 45, resulting in a continuous sheet 200 of homogenized tobacco material. The slurry is cast on the first surface 12 of the substrate sheet 11 facing the roll 45 .

The thickness of the sheet can be further controlled by lamination rolls 52,53. The moving roll 52 may be part of a pair of lamination rolls 52, 53 with a gap therebetween into which the sheet 200 is inserted. The lamination rolls 52 , 53 are used to facilitate absorption and wetting of the cellulosic fibers of the matrix sheet 11 and to achieve control of the final thickness of the sheet 11 .

The casting sheet 200 is driven in the conveying direction 14 by the moving rollers 52 and enters a heating unit (not shown in the figure), where it is gradually heated and uniformly dried.

The operation of the apparatus 110 for forming the homogenized tobacco sheet 200 is as follows. The slurry 22 formed, preferably without or with The storage tank (also not shown) is transferred to the casting box 42 . The casting roll 45 supplies the slurry onto the fiber-containing matrix sheet 11 by rotating while the matrix sheet 11 moves in the conveying direction 14 . The slurry layer is thus deposited on the first surface 12 of the substrate sheet 11 to form a homogenized tobacco sheet 200 .

The thickness and grammage per square meter of the sheet 200 controlled by the nucleometer immediately after the slurry feed is preferably continuously monitored and feedback controlled using a slurry measuring device.

In Figure 5, a third embodiment of an apparatus 120 for producing a homogenized tobacco sheet 200 is shown. Device 120 is similar to device 110 of Figure 4, so only the differences between the two devices will be outlined.

In addition to the casting roll 45 , the apparatus 120 also includes a second roll, a transfer roll 49 , in the casting box 42 . The transfer roll 49 is located below the casting roll 45 . The diameter of the transfer roll 49 is preferably larger than the diameter of the casting roll 45 . Preferably, the transfer roller 49 is cylindrical and defines a second axis of rotation 51 (indicated by a cross in FIG. 5 ) parallel to the first axis of rotation 48 . The transfer rolls 49 are preferably rotatably attached to the two opposite side walls of the casting box 42 by means of their longitudinal ends. Furthermore, transfer roll 49 is preferably located entirely within casting box 42 and is at least partially submerged by slurry 22 . The rotation direction of the transfer roll 49 is opposite to the rotation direction of the casting roll 45 .

A gap is formed between the casting roll 49 and the casting roll 45 .

The transfer roll 49 thus contacts the slurry and transfers it to the casting roll 45 which applies the slurry to the substrate sheet 11 as detailed with reference to the apparatus 110 .

In operation of the apparatus 120, the slurry 22 is fed to the casting box 42 at the inlet. The slurry reaches the given level. When the slurry 22 in the casting box reaches a given level, the transfer roll 49 is partially in contact with the slurry, and due to its rotation, its outer surface is covered with a layer of slurry 22 so that there is a slurry on the transfer roll 49 coating. The slurry coating in transfer roll 49 is transferred to casting roll 45 . The slurry is then transferred to the casting roll 45 due to the contact between the slurry layer on the transfer roll 49 and the surface of the casting roll 45 , where it is transferred to the casting roll 45 before it is finally transferred to the substrate sheet 11 . A slurry coating is formed on the surface.

Cast roll 45 rotates about axis 48 and the slurry layer contacts matrix sheet 11 . This results in the transfer of the slurry from the casting roll 45 to the substrate sheet, where the coating of the slurry forms the casting web 200 .

The web is then preferably dried and spooled for storage (not shown). These spools are then unrolled and used to make tobacco components for aerosol-generating articles.

In Figure 6, a fourth embodiment of an apparatus 130 for producing a homogenized tobacco sheet 200 is shown. Device 130 is similar to device 120 of Figure 5, so only the differences between the two will be outlined.

In addition to the configuration depicted with reference to apparatus 120 , apparatus 130 also includes a counterpressure roll 56 positioned above casting roll 45 . A gap is formed between the casting roll 45 and the counter-pressure roll. The matrix sheet 11 is positioned in this gap. The slurry 22 cast by the casting roll 45 reaches the substrate sheet and it is compressed between the casting roll 45 and the counter pressure roll 56 . Cast roll 45 and counter-pressure roll 56 press first surface 12 and second surface 13 of substrate sheet 11, respectively.

The amount of slurry coming out of the casting box 42 can then be controlled by adjusting the distance between the two rolls 45 and 49 (casting roll and transfer roll). In addition, the amount of slurry applied to the substrate sheet 11 can be adjusted by controlling the pressure applied to the sheet by the casting roll 46 and the counter-pressure roll 56 .

The pressure applied to the sheet helps to control the deposition of the slurry on the matrix sheet 11 well.

Apparatus 130 operates the same as apparatus 120 with the addition of compression by backpressure roll 56 .

As depicted in FIG. 7 , a graph is depicted for the concentrations of various components of the sheet of homogenized tobacco 200 . The continuous curve represents the concentration of the slurry in the sheet, while the dashed curve represents the concentration of the matrix-forming material. The abscissa of the figure represents the position in the matrix sheet 11 from the first surface 12 of the matrix sheet to the second surface 13 of the matrix sheet. If the slurry 22 is placed on one surface of the matrix sheet 11 that is the first surface 12, the slurry will have a decreasing concentration across the thickness of the matrix sheet from the first surface 12 to the second surface 13 (reported tobacco The mass of the sheet as a percentage of the total mass per unit volume).

Such reduced concentrations may vary with the formulation of the pulp, the distribution size of the tobacco particles, and the properties of the fibrous matrix 11 .

For example, the slurry content may drop from about 70-80% (the reported mass of tobacco compounds as a percentage of the total mass per unit volume) in the area of the first surface 12 where the slurry is applied to about 25% on the second surface 13 -20%. The fibrous matrix can vary from about 30-20% on the first surface 12 to about 75-80% in the area of the second surface 13 .

The shapes of the curves in Figure 7 are only schematic.

Homogenized tobacco sheet 200 of this configuration may be obtained using any of the apparatuses 10, 110, 120 and 130 of Figures 3-6.

The sheet of homogenized tobacco 200 may be a multilayer sheet or a sheet of composite material, depending on how the pulp is absorbed into the matrix sheet. FIG. 8 shows a multi-layer sheet 200 in which slurry 22 coats matrix sheet 13 to form second layer 201 . In FIG. 9 , substantially all of the slurry 22 is absorbed by the matrix sheet 13 and forms a composite sheet 200 .

Claims (14)

1. A multilayer sheet of alkaloid containing material, said multilayer sheet comprising:

-a first layer comprising a matrix sheet comprising fibers having an average fiber length of about 1 millimeter to about 5 millimeters, the first layer defining a first surface and a second surface;

-a second layer comprising a mixture of:

■, a powder of the alkaloid containing material, the powder having a size of about 8 microns to about 200 microns;

■ water;

■ a binder;

■ an aerosol former;

the second layer is applied to the first surface of the substrate sheet, and wherein the binder is included in an amount of about 0% to about 1% of the total weight of the multi-layer sheet of alkaloid containing material.

2. The multi-layer sheet of alkaloid containing material of claim 1, wherein the first layer is partially impregnated by the second layer.

3. The multi-layer sheet of alkaloid containing material according to claim 1 or 2, comprising a third layer comprising a mixture of:

●, a powder of the alkaloid containing material, the powder having a size of about 8 microns to about 200 microns;

● water;

● a binder;

● an aerosol former;

the third layer is applied to the second surface of the substrate sheet.

4. A sheet of a composite material containing an alkaloid, the sheet comprising:

a. a matrix sheet comprising fibers, the matrix sheet having a nominal average fiber length of about 1 millimeter to about 5 millimeters and defining a first surface and a second surface;

b. impregnating the substrate sheet with a mixture of:

i. a powder of the alkaloid containing material, the powder having a size of about 8 microns to about 200 microns;

ii, water;

a binder;

an aerosol former;

wherein the binder is included in an amount of about 0% to about 1% by total weight of the sheet of the alkaloid containing composite.

5. The multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material of any of the preceding claims, the sheet comprising a powder of the alkaloid containing material in an amount of about 40% to about 80% of the total weight of the multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material.

6. The multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material of any of the preceding claims, comprising water in an amount of about 7% to about 15% of the total weight of the multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material.

7. The multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material of any of the preceding claims, comprising an aerosol former in an amount of about 2.9% to about 8.5% of the total weight of the multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material.

8. The multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material of any of the preceding claims, comprising fibers other than the fibers of the alkaloid containing material in an amount of about 2% to about 5% of the total weight of the multi-layer sheet of alkaloid containing material or the sheet of alkaloid containing composite material.

9. The multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material of any of the preceding claims, wherein the multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material has a thickness of about 150 microns to about 400 microns.

10. The multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material of any of the preceding claims, wherein the multi-layer sheet of alkaloid containing material or sheet of alkaloid containing composite material has a width of about 0.1 meters to about 2.0 meters.

11. The multilayer sheet of alkaloid containing material or sheet of alkaloid containing composite material according to any of the preceding claims, wherein the powder of alkaloid containing material comprises tobacco powder.

12. The multilayered sheet of alkaloid containing material or the sheet of alkaloid containing composite material of any of the preceding claims, wherein the substrate sheet comprising fibers comprises cellulose fibers.

13. The multilayered sheet of alkaloid containing material or the sheet of alkaloid containing composite material of any of the preceding claims, wherein the substrate sheet comprising fibers comprises fibers derived from hemp, kenaf, bamboo, wood, cotton or silk.

14. An aerosol-generating article comprising a portion of a multilayer sheet of the alkaloid containing material or the sheet of the alkaloid containing composite material according to any of claims 1 to 13.

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