WO2018122305A1

WO2018122305A1 - Method to form a rod shaped article from a sheet of material

Info

Publication number: WO2018122305A1
Application number: PCT/EP2017/084707
Authority: WO
Inventors: Antonella Giannini; Stefano Malossi; Alberto Monzoni
Original assignee: Philip Morris Products S.A.
Priority date: 2016-12-29
Filing date: 2017-12-28
Publication date: 2018-07-05

Abstract

The invention relates to a method to form a rod shaped article from a sheet of material, the method including the steps of: - transporting the sheet of material in a transport direction; - providing a rod forming unit including an inlet and an outlet and at least three rollers; - inserting the sheet into the inlet of the rod forming unit and transporting it among the three rollers; - rotating the rod forming unit around the transport direction; and - outputting the rod shaped article from the rod forming unit.

Description

METHOD TO FORM A ROD SHAPED ARTICLE FROM A SHEET OF

MATERIAL

The invention concerns the manufacturing process of a rod shaped article from a sheet of material, and preferably the manufacturing process of a component of an aerosol generating article, such as a smoking articles, from a material in a sheet format.

Some aerosol generating articles may include one or more components which have a rod shape and are formed by a material which is at the beginning of the manufacturing process in a foil shape. The foil shape needs thus to be modified, for example compressed into a circular cylinder format, and then it may be wrapped and cut into sticks which will be part of the aerosol generating article.

In order to perform such compression, the foil is usually pulled through a funnel shaped device.

The compression, done by the funnel shaped device on a foil going through it, is a process which is somehow chaotic. In particular, the way in which the foil, at each moment in time, folds into a circular cylinder shape into the funnel- shaped device is not controlled or controllable. However, the way the foil folds has an impact on several key properties of the resulting stick of the aerosol generating article, and thus on the article itself, among which the RTD (Resistance to Draw) which is the amount of resistance users feel when drawing air through the article, or, in a more general way, properties relative to how the material will interact with the air drawn into the stick by users of the aerosol generating article.

Furthermore, pulling the foil into the funnel shaped device creates a lot of friction which can damage the material .

There is therefore a need of a method to form a rod shaped article from a sheet material in which a relatively low friction is experienced by the sheet and at the same time in which a control on the way the sheet folds on itself into a rod shape is possible at least to a certain extent.

The invention relates to a method to form a rod shaped article from a sheet of material, the method including the steps of transporting the sheet of material in a transport direction; providing a rod forming unit including an inlet and an l outlet and at least three rollers; inserting the sheet into the inlet of the rod forming unit and transporting it among the three rollers; rotating the rod forming unit around the transport direction; and outputting the rod shaped article from the rod forming unit. The method of the invention may create a twisting in the sheet, due to the rollers presence and the twisting of the rod forming unit that compresses the sheet into a rod shape while folding it with limited friction and in a way that can be controlled . Advantageously, this leads to a final rod shaped article the characteristics of which are controllable and in which circularity defects are reduced . Such method may replace or complete other methods used to compress a sheet into a rod shaped article, including the use of known regular funnel shaped devices.

Preferably, the rod shaped article is a component of an aerosol-generating article. In the following with "rod" a substantially rod shaped element is indicated, however its cross section does not need to be circular, any cross section is possible.

Further, the rod shaped article defines a longitudinal axis, meaning that one of its dimension is longer than the other two. The longitudinal axis is the axis along the longer dimension . Preferably, cross sections taken perpendicularly to the longitudinal axis are substantially identical in area, however different configurations can be present as well.

In the following, with the term "components" any element which may be included in an aerosol-forming article is meant. Such elements are known in the art and not further detailed below. For example, such component might include a plug of a filter, a heat source, a menthol capsule, a charcoal element, and so on.

As used herein, aerosol-generating article is any article that generates an inhalable aerosol when an aerosol-forming substrate is heated . The term includes articles that comprise an aerosol-forming substrate that is heated by and external heat source, such as an electric heating element. An aerosol- generating article may be a non-combustible aerosol-generating article, which is an article that releases volatile compounds without the combustion of the aerosol-forming substrate. An aerosol-generating article may be a heated aerosol-generating article, which is an aerosol-generating article comprising an aerosol-forming substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol. The term includes articles that comprise an aerosol forming substrate and an integral heat source, for example a combustible heat source.

An aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user's lungs through the user's mouth. An aerosol-generating article may resemble a conventional smoking article, such as a cigarette and may comprise tobacco. An aerosol-generating article may be disposable. An aerosol-generating article may alternatively be partially- reusable and comprise a replenishable or replaceable aerosol-forming substrate. In preferred embodiments, the aerosol-generating article may be substantially cylindrical in shape. The aerosol-generating article may be substantially elongate. The aerosol-generating article may have a length and a circumference substantially perpendicular to the length. The aerosol-generating article may have a total length between approximately about 30 millimeters and approximately about 100 millimeters. The aerosol-generating article may have an external diameter between approximately about 5 millimeters and approximately about 12 millimeters.

As used herein, the term "sheet" denotes a laminar element having a width and length substantially greater than the thickness thereof. The width of a sheet is preferably greater than 10 millimeters, more preferably greater than 20 millimeters or 30 millimeters. Even more preferably, the width of the sheet is comprised between about 100 millimeters and 500 millimeters. Preferably, the thickness of the sheet is comprised between about 20 micrometers and about 50 micrometers. The sheet of material used in forming the rod shaped article maybe any material common in the industry of aerosol generating articles. For example, it might be a plastic material sheet, such as a polyester sheet or PLA. In order to form a rod shaped article from a sheet, the sheet is introduced into a rod forming unit. The rod forming unit comprises an inlet and an outlet from which the sheet is inserted and then outputted as a rod shaped article. The sheet at the inlet folds in a shape for example having a diameter of between about 3 centimeters to about 6 centimeters. At the output of the rod forming unit, preferably the rod shaped article has a diameter from about 1 centimeter to about 2 centimeter, depending of the rotational speed of the overall rod forming unit, detailed below.

A channel from the inlet to the outlet in order to guide the sheet from one side to the other of the rod forming unit is formed by means of three rollers. The three rollers are preferably positioned so that two rollers contact the sheet on one side and one roller contact the sheet on an opposite side. More preferably, given a transport direction of the sheet into the rod forming unit which identifies an axis of the rod forming unit, two rollers - first and second roller - are positioned on one side with respect to the rod forming unit axis, and the third roller is positioned on the opposite side of the rod forming unit axis. More preferably, considering the axis of the rod forming unit as a coordinate axis, the third roller is positioned at a coordinate which is between the coordinates at which the first and second roller present on the other side of the axis are positioned . The coordinate which is taken as a reference for each roller as the "roller coordinate" is preferably the coordinate of the center of the roller. The third roller has the function of pressing on the "line" of the sheet created by the first and second roller, creating a gripping effect on the "line" of sheet, and so making possible to twist the sheet when the rod forming unit is turning on itself. Each roller is preferably rotatable in a direction substantially perpendicular to the transport direction of the sheet and thus the sheet is in contact with a side surface of the roller.

In addition to the rotation of the rollers, the rod forming unit is also rotatable on itself. The rotational axis is parallel to the direction of transport of the sheet. The rotational axis preferably is the rod forming unit axis above defined . The speed of the rotation can be controlled and varied if necessary. Preferably, the direction of rotation can be varied as well. The combined rotation around the transport direction and the rotation and compression of the rollers create a twisting effect on the sheet which is controllable and therefore the characteristics of the outputted rod formed article are controllable as well . Preferably, the step of transporting the sheet of material in a transport direction includes transporting the sheet of material at a speed comprised between about 200 meters/minute and about 500 meters/minute. This range is a preferred compromise between the speed of production and tension or forces applied on the sheet that should be below a certain threshold to avoid damages. Preferably, the step of providing a rod forming unit including an inlet and an outlet and at least three rollers includes providing a rod forming unit including an inlet and an outlet and at least three coplanar rollers. Preferably, the three rollers lie on a plane, so that their side surfaces define substantially a channel for the sheet from the inlet to the outlet which does not have unnecessary bends. The distances among the rollers along the axis of the rod forming unit determine - among others - the length of the rod forming unit.

Preferably, the step of providing a rod forming unit including an inlet and an outlet and at least three rollers includes providing a rod forming unit including an inlet and an outlet and at least three rollers, each roller having a rotational axis substantially perpendicular to the transport direction. The sheet of material is channeled from the inlet to the outlet by the side surfaces of the rollers which rotate in a direction substantially perpendicular to the transport direction.

Preferably, the method includes the step of pulling the rod shaped article downstream the rod forming unit. Preferably, in order to enter the rod forming unit, the sheet needs to be pulled in it, for example from the outlet side of the rod forming unit. This action can be performed for example by means of one or more rollers.

Preferably, the step of pulling the rod shaped article includes pulling the rod shaped article by means of a U-shaped conveyor belt. Preferably, after forming, the rod shaped article is also wrapped . In order to wrap the same, it is preferred to use a U shaped conveyor belt where a wrapping sheet can be positioned, already partially surrounding the rod shaped article.

Preferably, the step of inserting the sheet into the inlet of the rod forming unit and transporting it between the three rollers includes contacting the sheet by a circumferential surface of each of the three rollers. Each roller preferably comprises a side surface, which is substantially a cylindrical surface connecting two parallel surfaces substantially perpendicular to the rotation axis of the rollers. Preferably, the sheet is in contact with the side or circumferential surface of all the three rollers so that it can be transported and twisted while being transported from the inlet to the outlet of the rod forming unit.

More preferably, the circumferential surface is concave. The rollers have preferably concave transversal profiles creating, when the rod forming unit is spinning, a circular cross section around the sheet and into which the sheet is pulled . The concave profile grips the sheet and makes it spin on itself, creating a dynamic constraining and forming effect which compresses the sheet into a twisted rod . This dynamic constraining and forming effect creates constraint folding structures for the material passing through the rollers. Being the concave profile a controllable parameter, a better control on the structure of the cross section of the material inside the outputted rod shaped article is possible, and in turn also a better control on the consistency of the product and on key parameters of the final product, like its resistance to draw. Preferably, the maximum diameter of each roller, at the edges of the concave profile of the circumferential surface, is between about 5 centimeters and about 10 centimeters, while the minimum diameter at the middle of the concave profile is preferably comprised between about 3 centimeters and about 8 centimeters. More preferably, the step of contacting the sheet by a circumferential surface of each of the three rollers includes contacting the sheet of material at two opposite sides with respect to the transport direction by two different circumferential surfaces of two different rollers. Preferably, the at least three rollers have each a circumferential surface having a given width, the width of one of the circumferential surfaces being different from the widths of the circumferential surfaces of the other two rollers. More preferably, the method includes the step of arranging the at least three rollers with decreasing width of the circumferential surfaces along the transport direction. The sheet therefore experiences a "narrowing down" profile. Preferably, the width of the rollers is comprised between about 2 centimeters and about 5 centimeters. Having rollers with decreasing profiles width along the direction of the transport of the sheet allows to create a progressively compressing tube into which the sheet is pulled . A more "gentle" compression is thus achieved.

Preferably, the method includes the step of setting the rotating speed of the rod forming unit depending on a desired number of twists on the rod shaped article. This number of twists has a direct impact on the density and distribution of the material when in rod shape.

Preferably, the method includes the step of wrapping the rod shaped article in a wrapping sheet. Preferably, the rod shaped article is a component of an aerosol-generating article and thus it is preferably wrapped, for example in wrapping paper.

Preferably, the at least three rollers are free rollers. Free rollers allow minimizing friction. In addition, the angular speed of rotation of the rollers depends only on the travelling speed of the sheet. Preferably, the sheet of material is made of plastic material. More preferably, it is made of PLA.

Preferably, the inlet or the outlet of the rod forming unit is funnel-shaped . The insertion or the output of the sheet or rod shaped article into/from the rod forming unit is in this way facilitated . Preferably, a surface of the inlet or of the outlet in contact with the sheet or the rod shaped article is made of ceramic material. It is advantageous to coat or to form all surfaces which come into contact with the sheet in a material which generates low friction, to minimize damages to the sheet while being transported, due to the high speeds involved . The invention will be further described, by way of example only, with reference to the accompanying drawings in which :

Figure 1 is a top view in section of an apparatus operating according to the present invention; - Figure 2 is a perspective view of the apparatus of Figure 1; and

Figure 3 is a side view in section of a detail of the apparatus of Figure 1 or 2.

In figure 1 and 2, an apparatus for the production of rod shaped articles is depicted and globally indicated with 10. The apparatus 10 is adapted to obtain a rod-shaped article 1, such as a filter component, from a sheet 2 or foil of material, such as PLA.

The apparatus 10 includes a rod forming unit 11 which is rotatable for example by a motor connected to the unit via a belt (motor and belt not visible in the drawings) around the arrow 12 depicted in figure 1. The speed and the direction of rotation can be tunable.

The rod forming unit 11 includes an inlet 14 and an outlet 15 and a passageway 16 connecting the inlet and the outlet. The passageway 16 defines a longitudinal axis X which is preferably the same as the direction of transport (indicated by an arrow 18 in figure 1) of the sheet 2 inside the tubular element. The longitudinal axis is also the axis around which the rod forming unit rotates due to the action of the above mentioned motor. The passageway is formed by three free coplanar rollers, first, second and third roller 20, 21, 22 having each a rotational axis 23 perpendicular to the direction of transport of the sheet 2.

The rollers are positioned so that two rollers, first and second 20, 21, are on one side of the longitudinal axis X of the rod forming unit 11, while the third roller 22 is located on the other side of the axis X. All rollers are in contact with the sheet 2 while it passes into the rod forming unit 11. As shown in figure 3, the rollers are in contact to the sheet 2 by means of a side circumferential surface 24 which has a concave profile, so that the sheet 2 is gripped between substantially cylindrical surfaces. Further, the apparatus 10 may include a wrapping unit 30 positioned downstream the rod forming unit 11 in the direction of transport 19.

In operation, the sheet of material 2 is inserted into the inlet 14 of the rod forming unit 11. The insertion takes place for example pulling one side of the sheet 2 through the unit 11.

Depending on the desired product to be obtained, a transport speed of the sheet 2 is set, as well as an angular speed of rotation of the rod forming unit 11 around its longitudinal axis. Further, different profile of the circumferential surface 24 of the rollers 20, 21, 22 can be selected, The angular speed and the direction of rotation can be varied .

The sheet 1 is thus passing through the rod forming unit 11 being twisted by the combined action of the side concave surface of the rollers and the rotation around the X axis, forming a rod shaped article 1 outputted by the rod forming unit.

Claims

A method to form a rod shaped article from a sheet of material, the method including the steps of:

- transporting the sheet of material in a transport direction;

providing a rod forming unit including an inlet and an outlet and at least three rollers;

inserting the sheet into the inlet of the rod forming unit and transporting it among the three rollers;

rotating the rod forming unit around the transport direction; and

- outputting the rod shaped article from the rod forming unit.

The method according to claim 1, wherein providing a rod forming unit including an inlet and an outlet and at least three rollers includes:

providing a rod forming unit including an inlet and an outlet and at least three coplanar rollers.

The method according to claim 1 or 2, wherein providing a rod forming unit including an inlet and an outlet and at least three rollers includes: providing a rod forming unit including an inlet and an outlet and at least three rollers, each roller having a rotational axis substantially perpendicular to the transport direction.

The method of one or more of the preceding claims, including the step of:

pulling the rod shaped article downstream the rod forming unit.

The method according to claim 4, wherein pulling the rod shaped article includes:

pulling the rod shaped article by means of a U-shaped conveyor belt. The method according to any of the preceding claims, wherein inserting the sheet into the inlet of the rod forming unit and transporting it between the three rollers includes:

- contacting the sheet by a circumferential surface of each of the three rollers.

The method according to claim 6, wherein the step of contacting the sheet by a circumferential surface of each of the three rollers includes: - contacting the sheet of material at two opposite sides with respect to the transport direction by two different circumferential surfaces of two different rollers.

8. The method according to claim 6 or 7, wherein the at least three rollers have each a circumferential surface having a given width, the width of one of the circumferential surfaces being different from the widths of the circumferential surfaces of the other two rollers.

9. The method according to claim 8, including the step of:

- arranging the at least three rollers with decreasing width along the transport direction .

10. The method according to any of the preceding claims, including the step of:

- setting the rotating speed of the rod forming unit depending on a desired number of twits in the rod shaped article.

11. The method according to any of the preceding claims, including :

- wrapping the rod shaped article in a wrapping sheet.

12. The method according to any of the preceding claims, wherein the at least three rollers are free rollers.

13. The method according to any of the preceding claims, wherein the sheet of material is made of plastic material.

14. The method according to any of the preceding claims, wherein the inlet or the outlet of the rod forming unit is funnel-shaped .

15. The method according to any of the preceding claims, wherein a surface of the inlet or of the outlet in contact with the sheet or the rod shaped article is made of ceramic material.