Aerosol-generating articles, including insulating sleeves

Abstract

An aerosol-generating article (1) adapted to electrically heat an aerosol-generating device. The aerosol-generating article comprises an inner substrate core (3) containing an aerosol-generating substrate. The aerosol-generating article further comprises an insulating sleeve (5) surrounding the substrate core and an outer wrapper (7) surrounding the insulating sleeve. A method for producing an aerosol-generating article, an apparatus for producing an aerosol-generating article, and the use of acetate tow to wrap an aerosol-generating substrate of an aerosol-generating article.

Description

[Technical field]

[0001] The present invention relates to an aerosol-generating article. The present invention also relates to a method for producing an aerosol-generating article, an apparatus for producing an aerosol-generating article, and the use of acetate tow for wrapping an aerosol-generating substrate of an aerosol-generating article. [Background technology]

[0002] WO2018 / 206615A2 discloses an aerosol-generating article comprising a substrate core having a non-circular outer cross-section and a filler sleeve surrounding the substrate core. Summary of the Invention

[0003] According to a first aspect of the present invention there is provided an aerosol-generating article adapted to be electrically heated in an aerosol-generating device. The aerosol-generating article comprises an inner substrate core. The inner substrate core comprises an aerosol-generating substrate. The aerosol-generating article comprises an insulating sleeve surrounding the substrate core. The aerosol-generating article comprises an outer wrapper surrounding the insulating sleeve.

[0004] To generate an aerosol, the aerosol-generating substrate may be heated by a heating element disposed within the substrate core. The insulating sleeve reduces the amount of heat dissipated from the heating element to the outer surface of the aerosol-generating article. Thus, a higher portion of the generated heat remains within the substrate core and is available for generating an aerosol from the aerosol-generating substrate. More than 90 percent of the thermal energy that would otherwise be dissipated in the radial direction is preferably retained inside the inner substrate core by the insulating sleeve. As a result, the amount of energy consumed by the heating element may be reduced due to a lower heating temperature of the heating element or a shorter heating cycle. The heating temperature of the heating element may preferably be reduced by 20 percent compared to the heating temperature of a heating element of an aerosol-generating article without an insulating sleeve or of an aerosol-generating article made entirely of an aerosol-generating substrate. In particular, the heating temperature of the heating element may be set to a temperature that is favorable for releasing an aerosol from the aerosol-generating substrate. Thus, the energy storage in the aerosol-generating device, e.g., an electric battery, can be reduced in size or used for a longer time compared to an aerosol-generating device adapted to be used with an aerosol-generating article without an insulating sleeve or an aerosol-generating article made entirely of an aerosol-generating substrate. The surface of the aerosol-generating article can be kept cool and the possibility of overheating adjacent surfaces or surfaces in contact with the consumer can be prevented. In particular, the surface of the aerosol-generating article can remain at a lower temperature compared to an aerosol-generating article without an insulating sleeve. The aerosol-generating article can be at least partially inserted into or connected to the aerosol-generating device and together form a "heat-and-not-burn" system in which the aerosol-generating material is heated to release an aerosol but is not burned. In particular, the cavity or sidewall of the aerosol-generating device into which the aerosol-generating article may be inserted is protected from high temperatures. An outer wrapper can cover the insulating sleeve and preferably provide the consumer with the tactile and optical impression of the aerosol-generating article. The outer wrapper may provide additional stability to the aerosol-generating article.The insulating sleeve may allow for a wider range of materials for the outer wrapper since more heat sensitive materials may be used.

[0005] The insulating sleeve may comprise a porous material. The porous material may comprise a number of open or closed voids, in particular cavities filled with ambient air. The porous material may provide improved insulation compared to non-porous materials due to the low thermal conductivity of air. Preferably, 50 percent of the volume of the insulating sleeve may be void. The porous material may extend from the inner surface to the outer surface of the insulating sleeve, and thus may comprise air channels providing fluid exchange, in particular air exchange, between the insulating sleeve, e.g., the area surrounded by the inner substrate core, and the area outside the insulating sleeve. Furthermore, the air channels may extend from the inside to the surface of the insulating sleeve without extending through the entire insulating sleeve. Due to its low density, the porous material may have a reduced weight and require less material compared to a non-porous material having the same volume. The porous material may have an elasticity that may allow deformation during insertion of the aerosol-generating article into the aerosol-generating device to establish an essentially air-tight seal along the circumferential area of ​​the aerosol-generating article with the receptacle of the aerosol-generating device.

[0006] The insulating sleeve may comprise a fibrous material. The fibrous material may allow the elasticity of the insulating sleeve to be adapted to a preferred direction by appropriately arranging the fibers. The elasticity may be higher or lower in the direction of the fibers compared to the perpendicular direction. The fibers may therefore be arranged aligned mainly in one direction. Alternatively, the fibers may be arranged without a preferred direction to obtain an essentially constant elasticity in all directions. The fibrous material may comprise more air channels compared to non-fibrous materials and therefore provide a correspondingly higher air exchange between the inner and outer regions of the insulating sleeve. Thus, the longitudinal airflow through the inner substrate core may be supplemented with an airflow through the insulating sleeve essentially laterally or radially from the outside of the insulating sleeve into the inner substrate core. This may be useful for mixing the heated longitudinal airflow with the ambient air. The longitudinal direction is defined as the direction along the longest part of the aerosol-generating article. The radial or transverse direction is defined as the direction perpendicular to the longitudinal direction.

[0007] The fibrous material may include fibers that extend primarily in the longitudinal direction of the aerosol-generating article. This arrangement of fibers allows the insulating sleeve to be easily stretched in the longitudinal direction, which may be beneficial during the manufacturing process, but still provides circumferential stability. An airflow may be established in the insulating sleeve in a longitudinal direction parallel to the heated airflow through the inner substrate core, and both airflows can be merged in a predetermined location outside the inner substrate core, for example in the cooling section or mouthpiece section. The heated aerosol-containing airflow and the ambient airflow may be mixed downstream of the inner substrate core. Thus, the cooled airflow may reach, for example, the mouthpiece, without adversely affecting the aerosol generation in the inner substrate core.

[0008] The insulating sleeve may have the same or higher elasticity as the inner substrate core. This may create a stable structure of the aerosol-generating article and at the same time elasticity at the outer surface. Elasticity at the outer surface may be able to establish an airtight seal with the receptacle of the aerosol-generating device and additionally a comfortable tactile sensation for the consumer. Furthermore, a tight encapsulation of the inner substrate core by the insulating sleeve during manufacturing is possible.

[0009] The insulating sleeve may include acetate tow, which is a porous and stretchable material that can be processed to include a desired thickness and elasticity. Acetate tow is insulating.

[0010] The acetate tow may be a multidirectional expanded acetate tow web. The acetate tow may be stored and delivered in a compressed form or may be expanded during the manufacturing process. After expansion to a desired thickness and elasticity, an inner substrate core may be wrapped with the acetate tow.

[0011] The insulating sleeve may have a radial layer thickness that varies less than 10 percent from its average radial thickness, i.e., the radial layer thickness may be within a range of 90 percent to 110 percent of the average radial thickness. Preferably, the radial layer thickness of the insulating sleeve may vary less than 5 percent from its average radial thickness. The insulating sleeve may have a substantially constant circumferential layer thickness. Preferably, the cross section of the insulating sleeve may be a circular ring. Furthermore, the cross section of the insulating sleeve may be elliptical or rectangular. Preferably, when elliptical or rectangular, the insulating sleeve may have the greatest variability in layer thickness in the ranges specified above. The layers of material forming the insulating sleeve may encase the substrate core without overlapping regions. The insulating sleeve may provide substantially equal insulation in all radial directions, i.e., directions perpendicular to the longitudinal axis. Furthermore, the mechanical stability, e.g., stiffness or elasticity, may be substantially equal in all radial directions.

[0012] The insulating sleeve may be tubular. In particular, the insulating sleeve may be a hollow tube extending in the longitudinal direction of the aerosol-generating article. This may provide symmetric mechanical stability in all radial directions. The insulation may be substantially constant in all radial directions. Furthermore, the aerosol-generating article may be formed as a rod that can be inserted into a corresponding receptacle of the aerosol-generating device without the need for radial alignment or orientation.

[0013] The insulating sleeve and the substrate core may be coaxially aligned. The aerosol-generating article may be symmetric in all radial directions. Thus, the insulation may be constant in all radial directions. Furthermore, symmetric mechanical stability may be provided to the substrate core.

[0014] The substrate core may have an outer cross-section whose outer diameter is less than 5 percent longer than its minor diameter, and the insulating sleeve may have an inner cross-section corresponding to the outer cross-section of the substrate core. The substrate core may have a circular outer cross-section, and the insulating sleeve may have a circular inner cross-section corresponding to the circular outer cross-section of the substrate core.

[0015] The substrate core may have an elliptical cross section, with the major axis of the ellipse being more than 5 percent longer than the minor axis, and preferably less than 30 percent longer. The insulating sleeve may have an elliptical inner cross section that corresponds to the outer elliptical cross section of the substrate core.

[0016] The inner substrate core may be in contact with an insulating sleeve around its periphery, which may provide mechanical stability to the aerosol-generating article. The insulating material may be homogenous in all radial directions. Furthermore, air exchange through the porous insulating sleeve may be homogenous in all radial directions.

[0017] The aerosol-generating article may have a diameter of from 4.5 millimeters to 9 millimeters, preferably from 6 millimeters to 8 millimeters.

[0018] The susceptor may be disposed within the substrate core. The susceptor may be any material in which currents, in particular eddy currents, can be induced by magnetic induction, thus causing heating of the material. The material may be an electrically conductive, in particular a ferromagnetic material, in particular iron, aluminum, or steel. The excitation coil and the energy source may be disposed within an aerosol-generating device into which the aerosol-generating article may be inserted during use. Therefore, there is no need to insert an external heating element into the substrate core. Furthermore, the aerosol-generating article may be disposed to include the susceptor after use. Thus, each susceptor is used only for one aerosol-generating article, which may prevent degradation of the susceptor compared to repeated use of an external heating element.

[0019] The susceptor may be made of sheet material, which may be useful for inducing electrical current by magnetic induction. Additionally, a large surface may be created, which may be useful for distributing heat into the substrate core due to the extended contact area of ​​the susceptor with the aerosol-generating substrate. A susceptor formed as a sheet material may be relatively rigid against bending forces that may typically occur during manufacturing or handling of an aerosol-generating article for consumption.

[0020] The susceptor may have a width of 2.5 mm to 6 mm, preferably 3.5 mm to 5.5 mm. The width of the susceptor may correspond to the diameter of the inner substrate core.

[0021] The susceptor may have a thickness of 0.075 millimeters to 0.4 millimeters, preferably 0.1 millimeters to 0.3 millimeters.

[0022] The susceptor may be a plate, strip, sheet, band, or foil. These shapes provide flat, elongated surfaces that may provide a convenient contact area with the aerosol-generating substrate. Furthermore, these shapes are beneficial for material handling during the manufacturing process, particularly for handling the susceptor material as a continuous strip or web. Thus, the susceptor may be longitudinally, laterally (or both longitudinally and laterally) flexible.

[0023] The susceptor may be in contact with the insulating sleeve. This may stabilize the position of the susceptor and in particular prevent lateral movement of the susceptor. As a result, the susceptor remains fixed in place. When the aerosol-generating article is disposed in the aerosol-generating device, this may allow the susceptor to be reliably positioned in the aerosol-generating device at a location where the magnetic field of the magnetic induction coil is most dense or most homogeneous, or both. This may allow efficient heating of the susceptor, or a homogeneous temperature profile in the susceptor, or both. As a result, spots of temperature above the target temperature value are avoided in the susceptor and the aerosol-generating material may be heated at the intended predetermined temperature. The susceptor may have a width that essentially corresponds to the diameter of the inner substrate core or the circular inner cross section of the insulating sleeve, respectively. The presence of the aerosol-generating substrate in the inner substrate core may prevent the susceptor from rotating. As a result, the susceptors may be positioned diametrically along the inner substrate core of each of the insulating sleeves and across the central longitudinal axis of the aerosol-generating article.

[0024] The substrate core may have a diameter of 3.5 mm to 7 mm, preferably 4.5 mm to 6 mm. The susceptor may have a corresponding width. This may stabilize the position of the susceptor and in particular prevent lateral movement of the susceptor. Alternatively, the susceptor may have a width up to 20 percent smaller than the diameter of the substrate core. As a result, there may be a gap between the susceptor and the insulating sleeve or wrapper surrounding the substrate core.

[0025] The substrate core may include a conglomerate of tobacco material. The tobacco material may include one or more of powder, granules, pellets, pieces, spaghetti, strips, or sheets containing one or more of tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. Optionally, the tobacco plug may contain additional tobacco or non-tobacco, volatile flavor compounds that are released upon heating of the tobacco plug. Optionally, the tobacco plug may also contain capsules, for example, including additional tobacco or non-tobacco, volatile flavor compounds. Such capsules may melt during heating of the tobacco plug. Alternatively, or additionally, such capsules may be crushed before, during, or after heating of the tobacco plug.

[0026] When the tobacco plug includes homogenized tobacco material, the homogenized tobacco material may be formed by agglomerating particulate tobacco. The homogenized tobacco material may be in the form of a sheet. The homogenized tobacco material may have an aerosol former content of greater than 5 percent on a dry weight basis. Alternatively, the homogenized tobacco material may have an aerosol former content of 5 to 30 percent by weight on a dry weight basis. The homogenized tobacco material sheet may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuted one or both of tobacco lamina and tobacco stems, and alternatively, or additionally, the homogenized tobacco material sheet may include one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed, for example, during tobacco processing, handling and transportation. The homogenized tobacco material sheet may include one or more intrinsic binders (i.e., tobacco intrinsic binders), or one or more extrinsic binders (i.e., tobacco extrinsic binders), or a combination thereof, to assist in agglomerating the particulate tobacco. Alternatively, or in addition, the homogenized tobacco material sheet may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof. The homogenized tobacco material sheet is preferably formed by a casting process of a type that generally involves casting a slurry including particulate tobacco and one or more binders onto a conveyor belt or other supporting surface, drying the cast slurry to form a homogenized tobacco material sheet, and removing the homogenized tobacco material sheet from the supporting surface.

[0027] The substrate core may include a mass of crimped tobacco material. The crimped tobacco material may be a crimped cast leaf sheet. The crimped tobacco material may provide additional stability to the aerosol-generating article. The susceptor may be stably positioned within the crimped tobacco material within the inner substrate core.

[0028] The substrate core may include shredded tobacco material. Thus, the susceptor may be included within the inner substrate core during the manufacturing process without having to follow a specific orientation of the tobacco material. The same applies when a consumer inserts an external heating element immediately prior to consumption of the aerosol-generating article.

[0029] The substrate core may include a fibrous sensate medium, preferably with longitudinally extending fibers. This may beneficially affect airflow, as air channels may be formed by the fibrous sensate medium. Air channels may be formed longitudinally by the correspondingly extending fibers.

[0030] The outer wrapper may be formed by a flexible sheet material. This may facilitate a tight wrapping of the insulating sleeve. The outer wrapper may thus be prevented from moving relative to the insulating sleeve. In particular, the outer wrapper may prevent the insulating sleeve from slipping. The connection between the insulating sleeve and the outer wrapper may preferably be adhesive-free.

[0031] The outer wrapper may be made of paper or metal or plastic foil, or a combination thereof. Paper materials are lightweight, easy to process, and can be easily formed with printing on the outer surface. Metal foils can reflect heat away from the inner substrate core. Metal foils can prevent the aerosol-generating article from being accidentally ignited by a match or lighter. Plastic foils can be elastic to be tightly wrapped around the insulating sleeve. A combination of two or more materials, and therefore an outer wrapper comprising two or more layers, can be beneficial to combine the advantages of each.

[0032] The outer wrapper may be made of a porous material, which may facilitate air exchange from or into the insulating sleeve. Thus, airflow through the outer wrapper and through the insulating sleeve may be established. Thereby, the airflow through the insulating sleeve may flow radially into the inner substrate core or longitudinally in a direction toward the cooling section or mouthpiece section. Thus, the heated fluid or air in the inner substrate core or cooling section or mouthpiece section may mix with the ambient air.

[0033] The aerosol-generating article may include an inner wrapper disposed between the substrate core and the insulating sleeve and surrounding the substrate core, which may provide additional stabilization of the inner substrate core, particularly during the manufacturing process.

[0034] The inner wrapper may be formed of paper or metal or plastic foil, or a combination thereof. The materials may be selected to further tailor the insulation, or the air permeability, or both. The paper material may provide additional enclosure and thus stabilize the inner substrate core while retaining air permeability. The metal foil may provide insulation. The metal foil may prevent air exchange from the inner substrate core through the insulation sleeve, even if an open porosity material is used for the insulation sleeve. The combination of two or more materials for the inner wrapper, including two or more layers, may combine the aforementioned properties.

[0035] The inner wrapper may be made of a porous material, which may make it air permeable and may provide an adjustable air permeability function.

[0036] According to a second aspect of the invention, there is provided a method for manufacturing an aerosol-generating article. The method comprises the steps of conveying an aerosol-generating substrate in a conveying direction through a sleeve focusing device, feeding insulating material to the sleeve focusing device such that the insulating material is disposed circumferentially around the aerosol-generating substrate in the sleeve focusing device, and converging the insulating material to form an insulating sleeve around the aerosol-generating substrate. The method steps may be performed in this order. The method steps may be performed at least partly in parallel. The method may be performed in a continuous process, in particular a process for manufacturing an endless or continuous aerosol-generating article, which may be cut into single aerosol-generating articles of the desired length in the following method steps. Thus, an aerosol-generating article comprising at least two coaxially aligned layers can be efficiently manufactured in a continuous manufacturing process. Preferably, a tubular rod can be manufactured continuously.

[0037] The method may include the step of wrapping the insulating sleeve with an outer wrapper. Thus, a three-layer aerosol-generating article with a coaxial layer can be manufactured in a continuous process. This step may include applying an adhesive to keep the outer wrapper fixedly wrapped around the insulating sleeve. In particular, the outer wrapper may be wrapped around the insulating sleeve and may have an overlapping portion where two overlapping ends of the outer wrapper are glued together. Alternatively, the outer wrapper may be glued directly onto the insulating sleeve, thereby eliminating the overlapping portion of the outer wrapper.

[0038] The insulating material may include or consist of acetate tow. Acetate tow may include beneficial insulating properties. Additionally, acetate tow is a flexible material and may be processed in a continuous manufacturing process.

[0039] The method may include distributing the insulating material equally circumferentially within the sleeve focusing arrangement to form an insulating sleeve of substantially constant thickness. An equally shaped aerosol-generating article may be formed, i.e. a radially symmetric aerosol-generating article. The aerosol-generating article may preferably be formed as a tubular rod. Thus, the insulating properties may be constant along the circumference of the aerosol-generating article.

[0040] The insulating material may be fed to the sleeve focusing device in a single stream of insulating material, thus allowing continuous production of aerosol-generating articles, which single stream may then be fanned out for placement around the aerosol-generating substrate.

[0041] The insulating material may be fed to the sleeve focusing device in two or more separate streams of insulating material. The insulating sleeve may therefore be formed by bringing together the separate streams in the focusing device. It may therefore be sufficient to fan out a single separate stream only to a small extent. One stream may be placed over a first half of the aerosol-generating substrate and the other stream may be placed over a second half of the aerosol-generating substrate.

[0042] The step of supplying the insulating material may include guiding the insulating material along a guiding system. This may bring the insulating material into a preferred form and position, in particular in the form of a truncated cone, a hollow tube, or the like. These forms may still be open along their sides in the longitudinal direction, in particular in the conveying direction. This form may then be positioned around the aerosol-generating substrate in a sleeve focusing device, where it completely surrounds the aerosol-generating substrate, i.e. the inner substrate core.

[0043] The insulating material may be guided along a guiding surface of the guiding system, the guiding surface facing away from the aerosol-generating substrate. In particular, the normal vector of the guiding surface does not intersect with the aerosol-generating substrate. The guiding surface therefore provides a reaction force on the insulating material away from the aerosol-generating substrate. The insulating material may therefore be guided around the aerosol-generating substrate and then may wrap around the aerosol-generating substrate. The insulating material may be guided along the guiding surface of the guiding system under tension. This guiding may include stretching the insulating material. The tension of the insulating material may be reduced in a sleeve converging device. This may result in the insulating material converging such that it circumferentially encapsulates the substrate core. The converging insulating material may provide thermal insulation.

[0044] The method may include disposing a susceptor, particularly in the form of a continuous profile of susceptor, within an aerosol-generating substrate. Hence, a continuous or endless aerosol-generating article may be produced, comprising a heating element for heating the aerosol-generating substrate. The endless aerosol-generating article may then be cut into aerosol-generating articles having lengths for use by a consumer.

[0045] The method may include the step of arranging the susceptor in the aerosol-generating substrate, in particular in the form of individual susceptor segments. Arranging the susceptor in the aerosol-generating substrate in the form of individual susceptor segments allows the susceptor to be positioned laterally and longitudinally within the inner substrate core. The susceptor segments may have a length that is smaller than the longitudinal length of the inner substrate core. Thus, the susceptor segments may be arranged at a distance from one another within the continuous aerosol-generating substrate. The continuous aerosol-generating article may be cut into pieces of single aerosol-generating articles, each of which comprises one susceptor segment. The susceptor segments may have a longitudinal length that is smaller than the inner substrate core.

[0046] The method may include converging the aerosol-generating material and the susceptor to form an aerosol-generating substrate with the embedded susceptor. The aerosol-generating substrate may be an inner substrate core of the aerosol-generating article. By disposing the susceptor within the aerosol-generating material and converging both the susceptor and the aerosol-generating material, the susceptor may be placed in a preferred location within the aerosol-generating material, and this location may be stable. Because the susceptor does not need to be inserted into the aerosol-generating substrate in a subsequent manufacturing step or prior to use of the aerosol-generating article by a consumer, the aerosol-generating material is not adversely affected, e.g., displaced, by the insertion step.

[0047] The method may include wrapping the aerosol-generating material with an inner wrapper, which may support the structure and shape of the aerosol-generating material, preferably including a susceptor. This step may include applying an adhesive to maintain the inner wrapper fixedly wrapped around the aerosol-generating material. In particular, the inner wrapper may be wrapped around the aerosol-generating material and may have an overlapping portion where two overlapping ends of the inner wrapper are glued together. Alternatively, the inner wrapper may be glued directly onto the aerosol-generating material, thereby eliminating the overlapping portion of the inner wrapper.

[0048] According to a third aspect of the invention, there is provided an apparatus for manufacturing an aerosol-generating article comprising a guide system for forming an insulating sleeve of insulating material and a sleeve focusing device for encasing the aerosol-generating substrate in the insulating sleeve. Thus, an aerosol-generating article may be manufactured comprising an inner substrate core of aerosol-generating material coaxially surrounded by an insulating sleeve. The guide system may guide the insulating material around the aerosol-generating substrate. The guide system may comprise a section with an increasing diameter in a conveying or production direction relative to the central longitudinal axis and a section with a decreasing diameter in the conveying or production direction. The apparatus may be adapted to manufacture the aerosol-generating article in a continuous process. Furthermore, the apparatus may produce a continuous, in particular endless, rod. The continuous rod may then be cut into aerosol-generating articles having lengths for use by consumers.

[0049] The apparatus may further comprise a wrapper feeder for feeding an outer wrapper to be wrapped around the insulating sleeve. Thus, an aerosol-generating article is obtained comprising an inner substrate core and two coaxial layers, the insulating sleeve and the outer wrapper. The wrapper feeder may feed the outer wrapper into the sleeve converger such that both wrapping of the substrate core with the insulating sleeve and wrapping of the outer wrapper are at least partially performed by the sleeve converger.

[0050] The guiding system may comprise a guiding element providing a guiding surface along which the insulating material to form the insulating sleeve is guided, the guiding surface extending around an angle of at least 180 degrees. The insulating material may therefore be positioned around at least half of the strand of aerosol-generating material. A subsequent device may then encase the aerosol-generating material by converging the insulating material. The guiding system may be formed convexly relative to the central longitudinal axis. The guiding system may be formed convexly relative to the strand of aerosol-generating material that extends essentially along the central longitudinal axis.

[0051] The guiding system may comprise a first guiding element and a second guiding element, each providing a respective guiding surface along which the insulating material to form the insulating sleeve is guided. The two guiding elements may be arranged such that the insulating sleeve is essentially located around the strand of aerosol-generating material. The two guiding elements may be arranged on laterally opposite sides of the strand of aerosol-generating material. The strand of aerosol-generating material may be arranged between the first guiding element and the second guiding element. The first guiding element and the second guiding element may be spaced apart from each other. Either or both of the first guiding element and the second guiding element may have the shape of a cleft, a pair, a drop or a shoulder.

[0052] The sleeve convergence device may include a funnel. The funnel may guide the insulating sleeve into the sleeve convergence device.

[0053] The apparatus may comprise a substrate focusing device for forming the aerosol-generating substrate in the form of a rod. The substrate focusing device may be adapted to crimp a cast leaf sheet of tobacco to form a rod. The substrate focusing device may be adapted to form a rod of tobacco aggregates. The substrate focusing device may be adapted to form a rod of the aerosol-generating substrate including a susceptor disposed within the substrate.

[0054] The substrate focusing device may comprise a funnel. The funnel may guide the aerosol-generating substrate into the substrate focusing device.

[0055] The apparatus may comprise an expanding device comprising a first pair of expanding rollers adapted to guide the insulating material through the nip between the first pair of rollers. This may apply a force from the opposite side to the web of insulating material to expand the insulating material. Thus, the insulating material may be expanded to an increased thickness. The insulating material may be in a compressed state before the expanding device. The expanding device may further comprise a second pair of expanding rollers adapted to guide the insulating material through the nip between the second pair of rollers, which may be disposed successively to the first pair of expanding rollers to expand the web of insulating material. Thus, the expanding may be performed in a two-step process. Furthermore, tension may be applied between the first pair of expanding rollers and the second pair of expanding rollers, for example by a different rotation speed of the first pair of expanding rollers with respect to the second pair of expanding rollers. Thus, a high grade of expansion of the insulating material may be achieved.

[0056] The expansion roller may be a profiled roller to form a profile in the web of insulating material.

[0057] According to a fourth aspect of the present invention, there is provided the use of acetate tow to wrap an aerosol-generating substrate of an aerosol-generating article, in order to reduce heat dissipation from a heating element within the aerosol-generating substrate to the outer surface of the aerosol-generating article. Hence, the energy consumption of the heating element may be reduced. Furthermore, the outer surface of the aerosol-generating article may be prevented from reaching a temperature that is uncomfortable for the consumer or undesirable for materials, for example adjacent to the aerosol-generating device, into which the aerosol-generating article is inserted during use.

[0058] The heating element may be a susceptor provided as part of the aerosol-generating article, so that no external heating element needs to be inserted prior to use and no migration of the aerosol-generating material occurs.

[0059] The heating element may be a heating blade provided as part of a separate heating device, which is inserted into the aerosol-generating substrate to heat the aerosol-generating article. The inner substrate core may not include a susceptor. This may simplify the manufacturing process of the aerosol-generating article, as a susceptor does not need to be embedded within the inner substrate core.

[0060] An aerosol-generating article according to the first aspect of the invention may be manufactured by the method according to the second aspect of the invention. An apparatus for manufacturing an aerosol-generating article according to the third aspect of the invention may be used to manufacture an aerosol-generating article according to the first aspect of the invention. An apparatus for manufacturing an aerosol-generating article according to the third aspect of the invention may be used in the method according to the second aspect of the invention. Use of acetate tow according to the fourth aspect of the invention may be in an aerosol-generating article according to the first aspect of the invention. The embodiments will now be further described with reference to the figures. [Brief description of the drawings]

[0061] [Figure 1] FIG. 1 shows a perspective view of an aerosol-generating article. [Diagram 2] FIG. 2 shows a perspective view of an aerosol-generating article having an additional longitudinal element. [Diagram 3] FIG. 3 shows an apparatus for producing an aerosol-generating article. [Figure 4] FIG. 4 shows a schematic diagram of an integrated guidance system. [Diagram 5] FIG. 5 shows a schematic diagram of a two-piece guide system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] FIG. 1 shows an aerosol-generating article 1 comprising an inner substrate core 3, an insulating sleeve 5 surrounding the inner substrate core 3, and an outer wrapper 7 surrounding the insulating sleeve 5. The aerosol-generating article 1 has an outer surface 8. A susceptor 9 is disposed within the inner substrate core 3 for heating an aerosol-generating substrate 11. An inner wrapper 13 is disposed between the inner substrate core 3 and the insulating sleeve 5, encasing the inner substrate core 3. The aerosol-generating article 1 has a tubular rod shape and defines a longitudinal direction 100 along its longest extension and a radial direction 200 perpendicular to the longitudinal direction 100 and extending radially outward from a central axis 300. The aerosol-generating article 1 has a diameter 400 and the inner substrate core 3 has a diameter 500. The insulating sleeve 5 thus has a circumferential layer thickness 600. The circular outer cross section of the inner substrate core 3, defined by its diameter 500, is equal to the circular inner cross section of the insulating sleeve 5. The susceptor 9 has a width 701, a thickness 702, and a longitudinal length 703. The susceptor is formed of a sheet material, the longitudinal length 703 of which is greater than its width 701. The width 701 of the susceptor is greater than its thickness 702. The inner wrapper 13 and the outer wrapper 7 are made of a relatively thin material, e.g., a paper material, compared to the insulating sleeve 5 or the inner substrate core 3. The insulating sleeve 5 has an essentially constant circular layer thickness 600.

[0063] FIG. 2 shows a perspective view of an aerosol-generating article 1 having multiple longitudinal elements 801, 802, 803, 804, 805. The aerosol-generating article 1 comprises an inner substrate core 3 wrapped with an insulating sleeve 5, and comprises a longitudinal element 801 comprising a susceptor 9 disposed within the inner substrate core 3. In this embodiment, the width 701 of the susceptor 9 is equal to the diameter 500 of the inner substrate core 3 and is therefore in contact with the insulating sleeve 5. The longitudinal element 802 is disposed to the left of the element 801. The element 802 is formed as a hollow cylindrical tube and may function as a spacer for the bottom surface of the receptacle of the aerosol generating device into which the aerosol-generating article 1 is inserted. Furthermore, the element 802 may restrict the airflow through the aerosol-generating article 1 depending on its inner diameter. The element 803 is disposed to the right of the element 801. The element 803 is another hollow tube element formed, for example, of acetate tow. Element 803 functions as a cooling element to cool the heated airflow coming from the aerosol-generating substrate 11 of element 801. Element 803 may comprise a porous structure to mix the heated airflow with ambient air. Mouthpiece element 804 and filter element 805 are adjacent to the right of element 803. Mouthpiece element 804 is preferably formed of a moisture resistant material. Filter element 805 is preferably formed of acetate tow and filters the airflow.

[0064] 3 shows an apparatus 31 for manufacturing an aerosol-generating article 1, comprising a guiding system 33 for forming an insulating sleeve 5 of insulating material 35 and a sleeve converging device 37 for wrapping the aerosol-generating substrate 11 with the insulating sleeve 5. The guiding system 33 comprises a first guiding element 39 having a first guiding surface 41 and a second guiding element 43 having a second guiding surface 45. The insulating material 35 is guided along the outer first guiding surface 41 and the second guiding surface 45 to form the insulating sleeve 5 around the aerosol-generating substrate 11. Thus, the insulating material 11 is continuously conveyed through the spreading device 47 in the conveying direction 900. The spreading device 47 comprises a first pair of spreading rollers 49, 51 and a second pair of spreading rollers 53, 55 arranged consecutively to the first pair of spreading rollers 49, 51 to spread the web of insulating material 35. The insulating material 35 is guided through a nip 56 between a first pair of spreading rollers 49,51 and between a second pair of spreading rollers 53,55.

[0065] The apparatus 31 further comprises a substrate focusing device 57 for forming the aerosol-generating substrate 11 in the form of a rod. The aerosol-generating substrate 11 may initially be present as a cast leaf sheet 59, which is crimped together by the substrate focusing device 57. A continuous profile of susceptor 9 is fed into the aerosol-generating substrate 11, respectively into the cast leaf sheet 59, by the susceptor feeder 61. In the substrate focusing device 57, the susceptor 9 is disposed within the aerosol-generating substrate 11 and thus within the inner substrate core 3 of the final aerosol-generating article 1. A first wrapper feeder 63 feeds an outer wrapper 7 which is wound around the insulating sleeve 5 in the sleeve focusing device 37. A second wrapper feeder 65 feeds the aerosol-generating substrate 11, respectively the inner wrapper 13 which is wound around the inner substrate core 3 in the substrate focusing device 57. An adhesive feeder 67 applies adhesive onto the inner wrapper 13 and the outer wrapper 7. Thus, the inner wrapper 13 is secured to the aerosol-generating substrate 11 and the outer wrapper 7 is secured to the insulating sleeve 5 .

[0066] The sleeve convergence device 37 and the substrate convergence device 57 each include a funnel 69 for directing material into the device 37, 57, respectively.

[0067] 4 shows a schematic diagram of an integrated guiding system 33 with only one first guiding element 39. The first guiding element 39 guides the insulating material 35 around the aerosol-generating substrate 11 and extends at an angle of more than 180 degrees around the aerosol-generating substrate 11 to form an insulating sleeve 5. The insulating sleeve 5 is further converged in a sleeve convergence device 37 which is additionally guided by a funnel 69. The insulating material 35 is expanded by rollers 49, 51, 53, 55 of an expansion device 47 upstream of the guiding system 33.

[0068] 5 shows a schematic diagram of a two-piece guide system 33 comprising a first guide element 39 with a first guide surface 41 and a second guide element 43 with a second guide surface 45. The guide elements 39, 43 are arranged as upper and lower guide elements with a distance relative to each other and to the aerosol-generating substrate 11. The cross section of the guide element 43 first increases and then tapers towards the sleeve convergence device 37, the increase in cross section being higher than the decrease. Either or both of the first guide element 39 and the second guide element 43 may have the shape of a cleft, a pair, a drop or a shoulder. EXAMPLES

[0069] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0070] Example 1: An aerosol-generating article adapted to be electrically heated within an aerosol-generating device, the aerosol-generating article comprising an inner substrate core containing an aerosol-generating substrate, an insulating sleeve surrounding the substrate core, and an outer wrapper surrounding the insulating sleeve. Example 2: 2. The aerosol-generating article of example 1, wherein the insulating sleeve comprises a porous material. Example 3: 3. An aerosol-generating article as described in any one of Examples 1-2, wherein the insulating sleeve comprises a fibrous material. Example 4: An aerosol-generating article as described in example 3, wherein the fibrous material comprises fibers extending primarily along a longitudinal axis of the aerosol-generating article. Example 5: 5. An aerosol-generating article according to any one of Examples 1 to 4, wherein the insulating sleeve has the same or higher elasticity as the inner substrate core. Example 6: 6. An aerosol-generating article according to any one of Examples 1 to 5, wherein the insulating sleeve comprises acetate tow. Example 7: The aerosol-generating article of example 6, wherein the acetate tow is a multidirectional expanded acetate tow web. Example 8: An aerosol-generating article as described in any one of Examples 1-7, wherein the insulating sleeve has a radial layer thickness that varies by less than 10 percent. Example 9: An aerosol-generating article according to any one of Examples 1 to 8, wherein the insulating sleeve is tubular. Example 10: An aerosol-generating article according to any one of Examples 1 to 9, wherein the insulating sleeve and the substrate core are coaxially aligned. Example 11: An aerosol-generating article according to any one of Examples 1 to 10, wherein the substrate core has an outer cross-section whose outer diameter is less than 5 percent longer than its minor diameter, and the insulating sleeve has an inner cross-section corresponding to the outer cross-section of the substrate core. Example 12: 12. An aerosol-generating article according to any one of Examples 1 to 11, wherein the aerosol-generating article has a diameter of between 4.5 mm and 9 mm, preferably between 6 mm and 8 mm. Example 13: 13. An aerosol-generating article as described in any one of Examples 1 to 12, wherein the susceptor is disposed on a substrate core. Example 14: 14. The aerosol-generating article of example 13, wherein the susceptor is made of a sheet material. Example 15: 15. An aerosol-generating article according to any one of Examples 13 to 14, wherein the susceptor has a width of from 2.5 mm to 6 mm, preferably from 3.5 mm to 5.5 mm. Example 16: 16. An aerosol-generating article according to any one of Examples 13 to 15, wherein the susceptor has a thickness of 0.075 mm to 0.4 mm, preferably 0.1 mm to 0.3 mm. Example 17: 17. The aerosol-generating article of any one of Examples 13 to 16, wherein the susceptor is a plate, strip, sheet, band, or foil. Example 18: 18. The aerosol-generating article of any one of Examples 13 to 17, wherein the susceptor is in contact with an insulating sleeve. Example 19: 19. An aerosol-generating article according to any one of Examples 1 to 18, wherein the substrate core has a diameter of from 3.5 millimeters to 7 millimeters, preferably from 4.5 millimeters to 6 millimeters. Example 20: 20. An aerosol-generating article according to any one of Examples 1 to 19, wherein the substrate core comprises an aggregate of tobacco material, preferably an aggregate of crimped tobacco material. Example 21: 21. An aerosol-generating article according to any one of Examples 1 to 20, wherein the substrate core comprises shredded tobacco material. Example 22: 22. An aerosol-generating article according to any one of Examples 1 to 21, wherein the substrate core comprises a fibrous sensate medium, preferably having longitudinally extending fibers. Example 23: An aerosol-generating article according to any one of Examples 1 to 22, wherein the outer wrapper is formed from a flexible sheet material. Example 24: 24. The aerosol-generating article of any one of Examples 1 to 23, wherein the outer wrapper is formed from paper, metal foil, or plastic foil, or a combination thereof. Example 25: An aerosol-generating article according to any one of Examples 1 to 24, wherein the outer wrapper is made from a porous material. Example 26: 26. The aerosol-generating article of any one of Examples 1-25, further comprising an inner wrapper disposed between the substrate core and the insulating sleeve and surrounding the substrate core. Example 27: 27. The aerosol-generating article of Example 26, wherein the inner wrapper is formed from paper or metal foil or plastic foil, or a combination thereof. Example 28: 28. An aerosol-generating article according to any one of Examples 26-27, wherein the inner wrapper is made of a porous material. Example 29: 1. A method for producing an aerosol-generating article, the method comprising: conveying the aerosol-generating substrate in a conveying direction through a sleeve focusing device; providing an insulating material to the sleeve focusing device such that the insulating material is disposed circumferentially around the aerosol-generating substrate within the sleeve focusing device; and converging the insulating material to form an insulating sleeve around the aerosol-generating substrate. Example 30: The method of example 29, comprising wrapping the insulating sleeve with an outer wrapper. Example 31: 31. The method of any one of claims 29-30, wherein the insulating material comprises acetate tow. Example 32: The method of any one of claims 29-31, comprising distributing the insulating material evenly circumferentially within the sleeve convergence to form an insulating sleeve of substantially constant thickness. Example 33: The method of any one of claims 29-32, wherein the insulating material is fed to the sleeve convergence device in a single stream of insulating material. Example 34: The method of any one of embodiments 29-33, wherein the insulating material is fed to the sleeve convergence device in two or more separate streams of insulating material. Example 35: 35. The method of any one of Examples 29-34, wherein the step of providing the insulating material includes guiding the insulating material along a guiding system. Example 36: 36. The method of embodiment 35, wherein the insulating material is guided along a guiding surface of the guiding system, the guiding surface facing away from the aerosol-generating substrate. Example 37: The method of any one of Examples 29 to 36, comprising disposing a susceptor, particularly in the form of a continuous profile of susceptor, within the aerosol-generating substrate. Example 38: The method of any one of Examples 29 to 36, comprising disposing a susceptor, particularly in the form of an individual susceptor segment, within the aerosol-generating substrate. Example 39: The method of any one of Examples 29 to 38, comprising converging the aerosol-generating material and the susceptor to form an aerosol-generating substrate with the susceptor embedded therein. Example 40: The method of any one of Examples 29-39, comprising packaging the aerosol-generating material in an inner wrapper. Example 41: 1. An apparatus for producing an aerosol-generating article, comprising: a guide system for forming an insulating sleeve of insulating material; and a sleeve focusing device for encasing the aerosol-generating substrate in an insulating sleeve. Example 42: The apparatus of example 41, further comprising a wrapper supply for supplying an outer wrapper to be wrapped around the insulating sleeve. Example 43: An apparatus described in any one of Examples 41 to 42, wherein the guiding system comprises a guiding element providing a guiding surface along which the insulating material for forming the insulating sleeve is guided, the guiding surface extending around an angle of at least 180 degrees. Example 44: An apparatus described in any one of Examples 41 to 43, wherein the guiding system comprises a first guiding element and a second guiding element, each providing a respective guiding surface along which the insulating material to form the insulating sleeve is guided. Example 45: The apparatus of any one of Examples 41-44, wherein the sleeve convergence device comprises a funnel. Example 46: 45. The apparatus of any one of Examples 41 to 44, further comprising a substrate focusing device for forming an aerosol-generating substrate in the form of a rod. Example 47: The apparatus of Example 46, wherein the substrate focusing device comprises a funnel. Example 48: The apparatus of any one of Examples 41-47, further comprising an expansion device comprising a first pair of expansion rollers adapted to guide the insulating material through a nip between the first pair of expansion rollers. Example 49: The apparatus of example 48, wherein the expanding device further comprises a second pair of expanding rollers disposed in series with the first pair of expanding rollers for expanding the web of insulating material. Example 50: The apparatus of any one of Examples 48-49, wherein the expansion roller is a profiled roller and forms a profile in the web of insulating material. Example 51: The use of acetate tow to wrap an aerosol-generating substrate of an aerosol-generating article to reduce heat dissipation from a heating element within the aerosol-generating substrate to the outer surface of the aerosol-generating article. Example 52: The use of Example 51, wherein the heating element is a susceptor provided as part of the aerosol-generating article. Example 53: The use according to Example 51, wherein the heating element is a heating blade provided as part of a separate heating device, the heating blade being inserted into the aerosol-generating substrate to heat the aerosol-generating article.

[0071] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all cases as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A±10% of A. Within this context, the number A may be considered to include a numerical value that is within the general standard error for the measurement of the property that the number A modifies. The number A may deviate by the percentages recited above, in some cases as used in the appended claims, provided that the amount by which A deviates does not materially affect the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. An aerosol-generating article adapted to be electrically heated by an aerosol-generating device, comprising: an inner substrate core comprising an aerosol-generating substrate; an insulating sleeve surrounding the substrate core; an outer wrapper surrounding the insulating sleeve; a susceptor disposed within the substrate core, the susceptor contacting the insulating sleeve; The aerosol-generating article, wherein the susceptor is made of a sheet material.

2. 10. The aerosol-generating article of claim 1, wherein the insulating sleeve comprises a fibrous material.

3. 10. The aerosol-generating article of claim 1, wherein the insulating sleeve has a radial layer thickness that varies by less than 10 percent.

4. 2. The aerosol-generating article of claim 1, wherein the substrate core has an outer cross section whose outer diameter is less than 5 percent longer than its minor diameter, and the insulating sleeve has an inner cross section corresponding to the outer cross section of the substrate core.

5. 1. A method for producing an aerosol-generating article, said method comprising: conveying the aerosol-generating substrate in a conveying direction through a sleeve focusing device; supplying an insulating material comprising a fibrous material to the sleeve focusing device such that the insulating material is disposed circumferentially around the aerosol-generating substrate within the sleeve focusing device; converging the insulating material to form an insulating sleeve around the aerosol-generating substrate.

6. 6. The method of claim 5, wherein the step of converging the insulating material to form an insulating sleeve around the aerosol-generating substrate occurs in parallel with the step of conveying the aerosol-generating substrate through the sleeve converging device in the conveying direction.

7. 6. The method of claim 5, including the step of distributing the insulating material evenly circumferentially within the sleeve convergence device to form an insulating sleeve of substantially constant thickness.

8. The method of claim 5 , wherein the step of supplying insulating material comprises guiding the insulating material along a guide system.

9. 9. The method of claim 8, wherein the insulating material is guided along a guide surface of the guide system, the guide surface facing away from the aerosol-generating substrate.

10. The method of claim 5 , comprising converging an aerosol-generating material and a susceptor to form the aerosol-generating substrate with an embedded susceptor.

11. 1. An apparatus for producing an aerosol-generating article, comprising: a guide system for forming an insulating sleeve of insulating material; a sleeve convergence device for encasing the aerosol-generating substrate in the insulating sleeve.

12. The apparatus of claim 11 , wherein the sleeve convergence device comprises a funnel.

13. 12. The apparatus of claim 11, further comprising a wrapper feeder for feeding an outer wrapper to be wrapped around the insulating sleeve.

14. 12. The apparatus of claim 11, wherein the guide system comprises a first guide element and a second guide element, each providing a respective guide surface along which the insulating material to form the insulating sleeve is guided.

15. 12. The apparatus of claim 11, further comprising an expansion device comprising a first pair of expansion rollers adapted to guide the insulating material through a nip between the first pair of expansion rollers.

16. A use of acetate tow to wrap an aerosol-generating substrate of an aerosol-generating article in order to reduce heat dissipation from a heating element within the aerosol-generating substrate to the outer surface of the aerosol-generating article, wherein a susceptor is disposed within the substrate, the susceptor is in contact with the acetate tow, and the susceptor is made of a sheet material.

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