Applying an Additive from Within During Shaping of a Sheet into a Rod

This application is a divisional of U.S. application Ser. No. 18/030,712, filed Apr. 6, 2023, and which is a U.S. National Stage Application of International Application No. PCT/EP2021/077886 filed Oct. 8, 2021, which was published in English on Apr. 14, 2022, as International Publication No. WO 2022/074208 A2. International Application No. PCT/EP2021/077886 claims priority to European Application No. 20201034.4 filed Oct. 9, 2020.

The present disclosure relates to applying an additive, in particular a liquid, to a sheet material that is formed into a rod.

It is known from practice to supply sheet material to a shaping device to shape the sheet material into a rod. Such rods may be used in the production of smoking articles or other aerosol-generating articles.

It may be desirable to add one or more substances to the rod. For example, it may be desirable to add aerosol-generating substances or flavorful substances to the rod. There is a need for an efficient way of modifying the properties of a rod of sheet material by adding one or more substances.

According to an aspect of the invention, there is provided a method for producing a rod containing herbaceous material. The method comprises the step of providing a sheet material containing herbaceous material. The sheet material is shaped into a rod-shape by conveying the sheet material along a conveying direction through a funnel-shaped converging device. Within the converging device, an additive is dispensed onto the sheet material.

Providing the additive in the rod containing herbaceous material may facilitate heating the additive together with the herbaceous material, thereby facilitating release of substances, such as flavor components, from the additive.

The sheet material containing herbaceous material may be comparatively fragile. In particular, the sheet material containing herbaceous material may be more fragile than acetate fiber sheets, from which typical cigarette filters are made. Due to sheet material containing herbaceous material being comparatively fragile, it was unexpected that an additive could be dispensed onto the sheet material within the converging device without detrimental effects on the sheet material.

Dispensing the additive within the converging device may ensure that a high percentage of the dispensed additive or even (nearly) all of the dispensed additive is actually applied to the sheet material, thereby reducing waste of additive and contamination of equipment by the additive.

As the additive is dispensed onto the sheet material within the converging device, the additive may be dispensed onto the sheet material while the sheet material is shaped into the rod-shape. While the sheet material is shaped, the configuration of the sheet material may change, which may lead to an improved distribution of the additive over the sheet material. In particular, the additive may reach both sides (upper and lower sides) of the sheet material. The additive may enter folds in the sheet material created upon shaping the sheet material in the converging device.

A desired distribution of additive within the final rod-shape may be achieved by appropriately selecting the exact location of additive dispension within the converging device, for example. Dispensing the additive within the converging device may allow achieving a comparatively high additive concentration in the inner region of the final rod-shape with respect to a radial direction. By contrast, if the additive would, for example, be applied onto the final rod-shape after the rod-shape has left the converging device, the concentration of the additive might tend to always be high in radially outer regions of the rod-shape and low in radially inner regions of the rod-shape. Also, by contrast, if the additive would, for example, be sprayed onto the sheet material through a spray nozzle upstream of the sheet material entering the converging device, only one side (upper side or lower side) of the sheet material would be covered and there might be waste of additive due to some of the additive missing the sheet material.

The funnel-shaped converging device may comprise one or more walls that are engaged by the sheet material upon conveying the sheet material through the converging device. Contact between the one or more walls and the sheet material may reshape the sheet material, for example by one or more of bending, folding and compressing the sheet material.

The converging device may define a forming space through which the sheet material is conveyed. The forming space may at least partially be defined or delimited by one or more walls of the converging device.

The additive may comprise aerosol-generating substances, such as one or more of glycerin, glycerol, and propylene glycol, for example. The additive may comprise one or more flavorants, such as menthol, spearmint, peppermint,, vanilla, cocoa, chocolate, coffee, tea, spices (such as cinnamon, clove, and ginger), fruit flavorants, and combinations thereof. The additive may comprise nicotine.

The additive may be dispensed as a liquid. Dispensing the additive as a liquid may facilitate dispensing the additive. If the additive is dispensed as a liquid, distribution of the additive over the sheet material may be facilitated. The liquid may flow on the sheet material.

Preferably, the additive comprises methol. The additive may comprise menthol at a mass percentage of at least 40 percent, or of at least 50 percent, or of at least 70 percent, or of at least 80 percent, or of at least 90 percent, or of at least 95 percent. The additive may be pure menthol. Adding menthol may introduce a strong and attractive flavor component into the rod. Menthol may act as an aerosol-generating substance upon heating the rod. Menthol has a strong physical consistency and may be applied to the sheet material in a reproducible manner.

The sheet material may be a cast of a slurry containing herbaceous material or of a paste containing herbaceous material. The sheet material may be a cast leaf material, in particular a tobacco cast leaf material. The slurry or the paste may comprise one or more species of herbaceous material. Casting herbaceous material as a sheet allows the herbaceous material to be continuously supplied to the production process from a supply roll, for example.

The sheet material may comprise cut or ground herbaceous material. The cut or ground herbaceous material may, for example, comprise particulate herbaceous material having a particle size between 40 microns and 500 microns.

The herbaceous material may comprise homogenised plant material.

The herbaceous material may, for example, comprise tobacco material, or clove material, or a mixture of clove material and tobacco material. Tobacco material, or clove material, or a mixture of clove material and tobacco material may, but do not have to, account for 100 percent of the herbaceous material. The herbaceous material may comprise no tobacco particles and 100 percent clove particles, based on the dry weight of the herbaceous material. The herbaceous material may comprise between 10 percent and 60 percent by weight clove particles and between 40 percent and 90 percent by weight tobacco particles, more preferably between 30 percent and 40 percent by weight clove particles and between 70 percent and 60 percent by weight tobacco particles, based on the dry weight of the herbaceous material. The sheet material may, for example, comprise a total content of between 40 percent and 90 percent by weight tobacco particles and a total content of between 10 percent and 60 percent by weight clove particles, based on dry weight of the sheet material.

The sheet material may, for example, comprise one or more of eugenol, eugenol-acetate, and beta-caryophyllene. In particular, the sheet material may comprise at least 125 micrograms of eugenol per gram of the sheet material, on a dry weight basis; at least 125 micrograms of eugenol-acetate per gram of the sheet material, on a dry weight basis; and at least 1 microgram of beta-caryophyllene per gram of the sheet material, on a dry weight basis.

The sheet material may comprise at least one of cellulose fibers and glycerin. Cellulose fibers may strengthen the sheet material and make it more resistant to breaking or tearing. Glycerin may facilitate the production of aerosol upon heating the sheet material.

The sheet material may have a thickness of less than 1 millimeter, or of less than 0.5 millimeter, or of less than 0.2 millimeter, or of less than 0.1 millimeter, or of less than 0.05 millimeter. The sheet material may have a thickness of at least 0.001 millimeter, or of at least 0.01 millimeter, or of at least 0.1 millimeter. Sheet material having a comparatively low thickness may be easier to shape into the rod shape. Sheet material having a comparatively high thickness may be less likely to be torn or damaged upon dispensing the additive onto the sheet material.

The sheet material may be cast leaf material, in particular tobacco cast leaf material. Cast leaf material may be manufactured by grinding herbaceous material, in particular tobacco material, to powder. The powder may be mixed with adhesive or solvent, or adhesive and solvent, to obtain a slurry. The slurry may be formed and dried to obtain cast leaf material. The method may comprise manufacturing the cast leaf material as described. Alternatively, pre-produced cast leaf material could be used. Using cast leaf material as sheet material may facilitate forming the rod, as the cast leaf material may be conveniently supplied to the production process in a continuous manner, for example from a supply roll. Cast leaf material may be easy to manufacture, transport and store. Using cast leaf as sheet material may simplify the process of forming the rod due to comparatively high tensile strength of cast leaf material. Using tobacco cast leaf may ensure efficient nicotine delivery upon consumption. Cast leaf material may be manufactured at least partly from broken or physically damaged herbaceous material.

The method may comprise crimping the sheet material upstream of the converging device. Crimping the sheet material may facilitate shaping the sheet material into the rod-shape. If the sheet material is crimped, the sheet material may be more likely to form folds upon shaping the sheet material. Folds in sheet material may serve to receive additive dispensed onto the sheet material.

The shaping into a rod-shape of a particular section of the sheet material within the converging device may begin before the additive is dispensed onto the particular section of the sheet material. The shaping into a rod-shape of a particular section of the sheet material within the converging device may finish after the additive has been dispensed onto the particular section of the sheet material. The additive may be dispensed onto a particular section of the sheet material, while the particular section of the sheet material is undergoing shaping within the converging device. If the additive is dispensed onto a section of the sheet material that is currently shaped within the converging device, the additive may be integrated into the rod-shape upon shaping the rod-shape. The additive may be prompted to be distributed over the sheet material by the movement of the sheet material during shaping of the sheet material.

The additive may be dispensed onto the sheet material at a position within the converging device, at which a maximum diameter of the rod-under-formation is at most 400 percent, or at most 350 percent, or at most 300 percent, or at most 250 percent, or at most 200 percent, or at most 150 percent of a maximum diameter of the final rod-shape upon exiting the converging device. If the additive is dispensed onto the sheet material at a position within the converging device, where the sheet material has already been shaped or compressed to a certain degree, efficient distribution of the additive over the sheet material may be facilitated.

The additive may be dispensed onto the sheet material from within the rod-shape upon shaping the sheet material into the rod-shape. If the additive is dispensed from within the rod-shape, the additive may be distributed over the sheet material from an inner region of the rod-shape with respect to a radial direction. A concentration of additive may be highest in an inner region of the rod-shape and may decrease outwardly with respect to a radial direction. Dispensing the additive from within the rod-shape may ensure that most or (nearly) all of the dispensed additive actually finds its way onto the sheet material, thus reducing waste of additive.

The additive may be dispensed within the converging device through an end section of a pipe. The pipe may allow choosing a location within the converging device where the additive is dispensed, thereby increasing control over the dispensing process. The end section of the pipe may comprise a dispensing opening through which the additive is dispensed. The end section of the pipe may protrude into the converging device, in particular into a forming space of the converging device.

The end section of the pipe may at least essentially extend along the conveying direction. In particular, an angle between the end section of the pipe and the conveying direction may be less than 30 degrees, or less than 20 degrees, or less than 15 degrees, or less than 10 degrees, or less than 5 degrees, or less than 3 degrees, for example. If the end section of the pipe at least essentially extends along the conveying direction, the sheet material is essentially conveyed in parallel to the pipe. The sheet material may be conveyed along the end section of the pipe within the converging device. If the end section of the pipe and the conveying direction are essentially parallel to each, the risk that the sheet material is damaged by contact with the end section of the pipe is reduced. The sheet material may slide along the end section of the pipe. The sheet material may take along additive that is dispensed from the end section of the pipe, thereby facilitating the application of the additive onto the sheet material.

The sheet material may be compressed against the end section of the pipe by the funnel-shape of the converging device. If the sheet material is compressed against the end section of the pipe, transfer of additive dispensed from the end section of the pipe onto the sheet material may be particularly smooth. In particular, the sheet material may be compressed against the end section of the pipe by the funnel-shape of the converging device from around the whole circumference of the end section of the pipe. If the sheet material is compressed against the end section of the pipe from around the whole circumference of the end section of the pipe, all or nearly all of the additive dispensed by the end section of the pipe may be received by the sheet material.

The rod-shape may be formed around the end section of the pipe in an at least essentially coaxial arrangement between the rod and the end section of the pipe. This may reduce the likelihood of damaging the sheet material due to contact with the end section of the pipe and may ensure that all or most of the additive dispensed from the end section of the pipe reaches the sheet material.

An outer circumferential shape of the pipe within the converging device and upstream of the end section of the pipe may be different from an outer circumferential shape of the end section of the pipe. The outer circumferential shape of the pipe may change along the extension of the pipe to account for the different processing conditions along the pipe. The outer circumferential shape of the pipe influences the amount of space that may be occupied by the sheet material at a particular position along the conveying direction within the converging device. The outer circumferential shape of the pipe may change to account for an increasing compression of the sheet material along the conveying direction.

A wall thickness of the end section of the pipe may vary around a circumference of the end section of the pipe. Having a wall thickness that changes around the circumference of the end section of the pipe may allow having thicker regions that stabilize the end section of the pipe and, at the same time, having thinner regions that take less space from the sheet material and therefore reduce the risk of damaging the sheet material and still allow for an efficient compression of the sheet material. Also, a varying wall thickness of the end section of the pipe around a circumference of the end section of the pipe may allow to arrange the inner channel of the pipe more closely to the passing sheet material at the injection location. Thus, application of the additive onto the sheet material may be facilitated.

An outer circumferential surface of the end section of the pipe may have one or more flat portions. One or more flat portions in the outer circumferential surface of the end section of the pipe may facilitate providing one or more portions around the circumference of the end section of the pipe that have a reduced wall thickness. The sheet material may be compressed against the one or more flat portions of the end section.

Upstream of the end section of the pipe, an outer circumferential surface of the pipe may have a circular cross-section. The circular cross section may stabilize the pipe and reduce obstruction by the pipe of the path along which the sheet material is conveyed.

An inner circumferential surface of the end section of the pipe may have a circular cross-section. The circular cross-section may stabilize the pipe and may ensure a smooth and well-distributed flow of additive through the pipe.

An outer diameter of the pipe may decrease along the conveying direction. If the outer diameter of the pipe decreases along the conveying direction, the pipe may give additional space to the sheet material, when the sheet material proceeds along the conveying direction. This may allow the sheet material to be progressively compressed around the pipe along the conveying direction.

The end section of the pipe may be coated. The end section of the pipe may be coated with a friction reducing coating. The coating may form a radially outmost layer of the end section of the pipe. The coating of the end section of the pipe may reduce friction between the sheet material and the end section of the pipe, thereby reducing the likelihood of damaging the sheet material, when conveying the sheet material along the end section of the pipe.

The friction reducing coating may, for example, be a diamond-like-carbon coating (DLC coating).

According to another aspect of the present invention, there is provided a device for producing a rod from sheet material. The device comprises a funnel-shape converging device, a conveyer device and a pipe. The conveyer device is configured to convey sheet material along a conveying direction through the funnel-shaped converging device. The pipe has an end section configured for dispensing an additive from the end section within the converging device. A wall thickness of the end section of the pipe varies around a circumference of the end section of the pipe.

As the additive is dispensed from the end section of the pipe within the converging device, the additive may be dispensed onto the sheet material while the sheet material is shaped within the converging device, thus facilitating distribution of the additive over the sheet material in a controlled and efficient manner.

As the wall thickness of the end section of the pipe varies around the circumference of the end section of the pipe, the pipe comprises portions with a greater wall thickness end portions with a smaller wall thickness around its circumference. The portions of smaller wall thickness may leave an increased amount of space for the sheet material within the converging device. Further, the portions of smaller wall thickness may allow bringing the sheet material particularly near the additive dispensed from the end section of the pipe. The portions having a greater wall thickness may ensure stability and structural integrity of the end section of the pipe.

The additive may be dispensed as a liquid.

The end section of the pipe may comprise a dispensing opening for dispensing the additive. The dispensing opening may be located at an end face of the end section.

The converging device may be configured to shape the sheet material into a rod-shape.

An outer surface of the end section of the pipe may have non-circular cross-section. For example, the cross-section of the outer surface of the end section of the pipe may be triangular, or rectangular, or polygon-shaped. A non-circular outer cross section of the end section of the pipe may provide a wall thickness of the end section of the pipe that varies around the circumference of the end section of the pipe.

An outer circumferential surface of the end section of the pipe may have at least one flat portion. The outer circumferential surface of the end section of the pipe may have curved portions between adjacent flat portions with respect to a circumferential direction.

An angle between a first flat portion of the end section of the pipe and a second flat portion of the end section of the pipe may be between 50 degrees and 70 degrees, or between 55 degrees and 65 degrees, or between 80 degrees and 100 degrees, or between 85 degrees and 95 degrees, for example. The angle may be measured in a cross sectional view with a sectional plane that is perpendicular to the extension direction of the pipe. Between the first flat portion and the second flat portion, there may be a curved portion. The curved portion may support structural integrity of the end section of the pipe.

An inner circumferential surface of the end section of the pipe may have a circular cross-section.

The end section of the pipe may at least essentially extend along the conveying direction. In particular, the end section of the pipe may at least essentially extend in parallel to the conveying direction. The end section of the pipe may at least be essentially straight.