Method for manufacturing an inductively heatable aerosol-forming substrate

Abstract

The method for manufacturing an inductively heatable aerosol-forming substrate comprises the steps of providing a tobacco containing slurry, providing an inductively heatable continuous sheet-like material and joining the tobacco containing slurry and the inductively heatable continuous sheet-like material to form an inductively heatable aerosol-forming substrate. A further step comprises drying the inductively heatable aerosol-forming substrate while transporting the inductively heatable aerosol-forming substrate on a conveyor device.

Claims

1. Method for manufacturing an inductively heatable aerosol-forming rod comprising an inductively heatable aerosol-forming substrate, the method comprising: providing a tobacco containing slurry; providing an inductively heatable continuous sheet-like material; joining the tobacco containing slurry and the inductively heatable continuous sheet-like material to form an inductively heatable aerosol-forming substrate; drying the inductively heatable aerosol-forming substrate while transporting the inductively heatable aerosol-forming substrate on a conveyor device; forming the inductively heatable aerosol-forming substrate into a rod by gathering or folding the inductively heatable aerosol-forming substrate, wherein the inductively heatable continuous sheet-like material is homogenously distributed over the cross section of the rod.

2. Method according to claim 1, comprising the steps of: supplying either one of the inductively heatable continuous sheet-like material or the tobacco containing slurry onto the conveyor device; depositing either the tobacco containing slurry onto the inductively heatable continuous sheet-like material being transported on the conveyor device or depositing the inductively heatable continuous sheet-like material onto the tobacco containing slurry being transported on the conveyor device.

3. Method according to claim 1, wherein the step of joining the tobacco containing slurry and the inductively heatable continuous sheet-like material comprises supplying the tobacco containing slurry onto the inductively heatable continuous sheet-like material before the so formed inductively heatable aerosol-forming substrate is arranged and transported on the conveyor device.

4. Method according to claim 3, providing a coater for supplying the tobacco containing slurry onto the inductively heatable continuous sheet-like material.

5. Method according to claim 3, wherein the inductively heatable continuous sheet-like material is a non-porous or closed sheet.

6. Method according to claim 2, providing a coater for supplying the tobacco containing slurry onto the conveyor device or the inductively heatable continuous sheet-like material.

7. Method according to claim 1, wherein the inductively heatable aerosol-forming substrate is transported on a heated conveyor belt, thereby drying the inductively heatable aerosol-forming substrate.

8. Method according to claim 1, providing the inductively heatable continuous sheet-like material in the form of a foil, mesh or web.

9. Method according to claim 1, wherein the inductively heatable continuous sheet-like material is a continuous metallic susceptor material.

10. Method according to claim 1, wherein the tobacco containing slurry comprises tobacco particles, fiber particles, aerosol former and binder.

11. Method according to claim 1, wherein the inductively heatable continuous sheet-like material has a thickness in between 10 micrometer and 70 micrometers.

12. Method according to claim 11, wherein the inductively heatable continuous sheet-like material has a thickness in between 20 micrometers and 30 micrometers.

13. Method according to claim 1, wherein the homogeneous distribution of the inductively heatable continuous sheet-like material over the cross section of the rod allows to heat the rod such that temperatures between a central region of the rod and a peripheral region of the rod differ by less than 50 percent.

14. Method according to claim 13, wherein temperatures between the central region of the rod and the peripheral region of the rod differ by less than 30 percent.

15. Method according to claim 1, wherein the inductively heatable continuous sheet-like material is a multi-material susceptor sheet.

16. Method according to claim 15, wherein the multi-material susceptor sheet comprises a first susceptor material primarily for heating the inductively heatable aerosol-forming substrate and a second susceptor material primarily used as temperature indicator.

Description

(1) The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein:

(2) FIG. 1 is a schematic illustration of an embodiment of a manufacturing process for an inductively heatable aerosol-forming substrate;

(3) FIG. 2 is an enlarged view of the inductively heatable aerosol-forming substrate, for example of FIG. 1;

(4) FIG. 3 is a schematic illustration of another embodiment of a manufacturing process.

(5) As illustrated in FIG. 1, a sheet of susceptor material 12, for example a foil, is unwound from a bobbin 2 and supplied to a conveyor belt 3. The conveyor belt 3 is a closed-loop conveyor belt. The moving direction of the upper section of the conveyor belt 3 corresponding to the transport direction of the susceptor sheet 12 on the conveyor belt is indicated with arrow 100. Before the susceptor sheet 12 is supplied to the conveyor belt 3, a layer of aerosol-forming substrate 11 is applied onto the susceptor sheet 12 by a coater 4. In FIG. 1, the coater is embodied as reverse roller coater. A slurry of aerosol-forming substrate 111 is provided in a reservoir of the coater 4. The slurry 111 passes through a slit between an application roller 40 and a metering roller 41. A support roller 42 is arranged below the susceptor sheet 12 for supporting and aligning the sheet 12 below the coater 4. The sheet 12 with the slurry 111 applied thereon is then supplied to the conveyor belt 3. While being transported along the conveyor belt 3, the slurry 111 may be dried, preferably by the heated conveyor belt 3. After drying and possibly cooling, the so manufactured inductively heatable aerosol-forming substrate 1 may be used for the production of an inductively heatable aerosol-generating article. The inductively heatable aerosol-forming substrate 1 may, for example, be gathered and crimped and formed into a rod shape. The inductively heatable aerosol-forming substrate 1 with a layer of aerosol-forming substrate 11 on a layer of susceptor material 12 is shown in more detail in FIG. 2. The thickness of the inductively heatable substrate is between 0.1 millimeter and 2 millimeter. Thickness variations of the layer of aerosol-forming substrate 11 may be much higher than of the layer of susceptor material 12 due to manufacturing tolerances of up to 30 percent of the layer of aerosol-forming substrate 11.

(6) In FIG. 3 the same reference numbers are used for the same or similar elements. FIG. 3 shows a manufacturing process, where the aerosol-forming slurry 111 is applied to a sheet-like susceptor material 12, at a time and position, where the susceptor material is already arranged and transported on the conveyor belt 3. A coater 4 is arranged at an upstream position of the conveyor belt 3. The coater 4 is embodied as a gate coater with a reservoir 44 holding slurry of aerosol-forming substrate 111. The bottom of the reservoir 44 has a slit 43 through which the slurry 111 may leave the coater 4. The slit is arranged most upstream of the transport section on the conveyor belt 3. Preferably, the transport section along which the inductively heatable substrate 1 is transported on the conveyor belt 3 is arranged horizontally or substantially horizontally (for example with a tilting angle less than plus or minus 10 degree). With a horizontal arrangement a flow of slurry into a direction other than the direction versus the susceptor 12 may be prevented.

(7) In the embodiment shown in FIG. 3, the sheet-like susceptor material 12 may be a foil, but may also be a porous material, such as a web or mesh. Due to the susceptor material being arranged on the conveyor belt 3 no slurry 111 applied onto the susceptor may fall through interstices or openings of the susceptor 12. However, the slurry 111 may penetrate into the openings or interstices in the susceptor material. By this, a stronger interface may be achieved between substrate and susceptor material. The susceptor material may also be embedded in aerosol-forming substrate.

(8) An embodiment, where the susceptor 12 is supported by the conveyor belt 3 when slurry 111 is applied, is also favourable for applications of very fragile sheet-like susceptor materials.

(9) The embodiments shown in the figures are examples only and it is obvious that many variations are within the scope of the invention. For example, the arrangement of a layer of tobacco containing substrate and the susceptor material may be reversed. For example, an aerosol-forming slurry may be applied to the conveyor belt. During manufacturing, the susceptor material is then provided on top of the layer of slurry. Preferably, the susceptor material is a porous material when applied on top of slurry, such that moisture and other volatile substances may pass through the susceptor material upon drying of the slurry. The conveyor belt may be provided with openings to support removal of moisture from the slurry arranged on the conveyor belt. Preferably, such openings in the conveyor belt are small enough for slurry to not be able to pass through but large enough for moisture to pass through.

(10) A joining of tobacco containing slurry and inductively heatable material may also be performed in a batch wise manner. The inductively heatable material may then be laid onto a support, while the slurry is applied to the inductively heatable material or vice versa. Before or after the slurry has dried, the inductively heatable aerosol-forming substrate is removed and a new layer of inductively heatable material or slurry may be provided on the support.