Rod with wrapper comprising gluing cavities

Abstract

The invention relates to a cylindrical rod (10) for aerosol-generating articles comprising a rod component (12) being circumscribed by a wrapper (14). The wrapper comprises laterally opposed edge portions which overlap so as to form an overlapping zone (16). Glue (24) is applied to the overlapping edge portions of the wrapper, by which the overlapping edge portions are adhered to each other. The glue is applied in such way, so as to form one or more glue zones (22) within the overlapping zone. The wrapper further comprises a plurality of cavities (26), wherein at least a part of the cavities is provided in the one or more glue zones. The invention further relates to a method for preparing a cylindrical rod for aerosol-generating articles.

Claims

1. A cylindrical rod for aerosol-generating articles comprising a rod component being circumscribed by a wrapper; the wrapper comprising: laterally opposed edge portions which overlap so as to form an overlapping zone, wherein the overlapping zone comprises an inner layer of the wrapper and an outer layer of the wrapper, and wherein the outer layer of the wrapper comprises an inner surface of the outer layer of the wrapper being located adjacent to the inner layer of the wrapper; glue being applied between the overlapping edge portions of the wrapper so as to form one or more glue zones within the overlapping zone; and a plurality of cavities, wherein at least part of the cavities are provided in the area of the one or more glue zones; characterized in that the inner surface of the outer layer of the wrapper comprises cavities which do not penetrate completely through the wrapper so as to define recesses in the wrapper, and the inner layer of the wrapper in the overlapping zone comprises cavities which penetrate completely through the wrapper so as to define through-holes in the wrapper.

2. The cylindrical rod according to claim 1, wherein the wrapper comprises cavities in the overlapping zone, only.

3. The cylindrical rod according to claim 2, wherein the wrapper comprises cavities in the one or more glue zones, only.

4. The cylindrical rod according to claim 1, wherein the recesses in the outer layer of the wrapper coincide with the through-holes in the inner layer of the wrapper.

5. The cylindrical rod according to claim 1, wherein the cavities are arranged in one or more lines in parallel to the longitudinal axis of the rod.

6. The cylindrical rod according to claim 5, wherein the cavities are equidistantly arranged in one line with a nearest neighbor distance of between 0.1 millimeter and 0.3 millimeter.

7. The cylindrical rod according to claim 1, wherein the outer layer of the wrapper comprises an outer surface of the outer layer of the wrapper opposite to the inner surface of the outer layer of the wrapper, and wherein the outer surface of the outer layer of the wrapper does not comprise any cavities.

8. The cylindrical rod according to claim 1, wherein only the inner layer of the wrapper comprises through-holes.

9. The cylindrical rod according to claim 1, wherein the glue penetrates completely through at least one of the through-holes such that the glue adheres the rod component to the wrapper.

10. The cylindrical rod according to claim 1, wherein the thickness of the wrapper is between 0.02 millimeter and 0.2 millimeter, and wherein the diameter of each through-hole is smaller than four times the thickness of the wrapper.

11. The cylindrical rod according to claim 1, wherein the diameter of each through-hole is less than 0.4 millimeter.

12. An aerosol-generating article comprising a cylindrical rod according to claim 1 and an aerosol-generating material.

13. A method for preparing a cylindrical rod for aerosol-generating articles, comprising the steps of providing a wrapper; providing a plurality of cavities in a lateral edge portion of the wrapper; providing a rod component; placing the rod component on a surface of the wrapper; applying glue on the lateral edge portion of the wrapper; and circumscribing the rod component with the wrapper such that laterally opposed edge portions of the wrapper define an overlapping zone of the wrapper, wherein the overlapping zone comprises an inner layer of the wrapper and an outer layer of the wrapper, and wherein the outer layer of the wrapper comprises an inner surface of the outer layer of the wrapper being located adjacent to the inner layer of the wrapper; and such that the glued area defines one or more glue zones within the overlapping zone, wherein at least part of the cavities are provided in the area of the one or more glue zones; characterized in that the inner surface of the outer layer of the wrapper comprises cavities which do not penetrate completely through the wrapper so as to define recesses in the wrapper, and the inner layer of the wrapper in the overlapping zone comprises cavities which penetrate completely through the wrapper so as to define through-holes in the wrapper.

14. The method according to claim 13, wherein the recesses in the outer layer of the wrapper coincide with the through-holes in the inner layer of the wrapper.

15. The method according to claim 13, wherein the outer layer of the wrapper comprises an outer surface of the outer layer of the wrapper opposite to the inner surface of the outer layer of the wrapper, and wherein the outer surface of the outer layer of the wrapper does not comprise any cavities.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 shows a cross-sectional view of a cylindrical rod for aerosol-generating articles of the invention;

(3) FIG. 2 shows a cross-sectional view at the glue zone of a first embodiment of a cylindrical rod for aerosol-generating articles of the invention;

(4) FIG. 3 shows a cross-sectional view at the glue zone of a second embodiment of a cylindrical rod for aerosol-generating articles of the invention;

(5) FIG. 4 shows a cross-sectional view at the glue zone of a third embodiment of a cylindrical rod for aerosol-generating articles of the invention.

(6) FIG. 1 shows a cross-sectional view of a cylindrical rod for aerosol-generating articles 10 of the invention. The rod 10 comprises a rod component 12 which is circumscribed by a wrapper 14. Laterally opposed edge portions of the wrapper 14 overlap in an overlapping zone 16. In the overlapping zone 16 overlapping edge portions of the wrapper 14 form an inner layer 18 of the wrapper 14 which is covered by an outer layer 20 of the wrapper 14. In a glue zone 22 glue 24 is applied between the overlapping layers 18,20 of the wrapper 14. Cavities 26 are not depicted in FIG. 1.

(7) FIG. 2 shows a cross-sectional view at the glue zone 22 of a first embodiment of a cylindrical rod for aerosol-generating articles 10 of the invention. In the glue zone 22, glue 24 is applied between the inner layer 18 of the wrapper 14 and the outer layer 20 of the wrapper 14, by which the overlapping edge portions of the wrapper 14 are adhered to each other.

(8) Further, in the embodiment of FIG. 2 only the outer layer 20 comprises cavities 26. Thus, the inner layer 18 does not comprise any cavities 26. Moreover, only the inner surface of the outer layer 20 comprises cavities 26. Thus, the outer surface of the outer layer 20 does not comprise any cavities 26. The cavities 26 are recesses. Accordingly, the cavities 26 are not visible from the outside. Thereby, the visual appearance of the cylindrical rod 10 is not altered by the presence of the cavities 26.

(9) The cavity 26 creates a caved surface of the wrapper 14. The cavity 26 is filled with glue 24. The glue 24 filling the cavity 26 acts like an anchor preventing the overlapping layers 18,20 of the wrapper 14 to move with respect to one another. The surface area of the wrapper 14 in the glue zone 22 is increased by the presence of the cavity 26. Accordingly, the total glued surface area of the wrapper 14 is increased by the presence of the cavity 26 which improves adhesion.

(10) The wrapper 14 is made of a fibrous material. Wrapper fibers 28 are substantially aligned parallel to the plane of the wrapper 14. Therefore, inside the cavity 26 the wrapper fibers 28 are substantially aligned perpendicular to cavity axis 30. In effect, spikes are formed by wrapper fibers 28 at the surface of the cavity 26. Accordingly, the surface of the cavity 26 is roughened. The surface area is increased due to the roughening in comparison to a smooth outer surface. Hence, the total glued surface area of the wrapper 14 is additionally increased by the roughening of the surface. Thus, adhesion is additionally improved due to the roughening of the surface.

(11) Moreover, the roughened surface provides many additional anchorages for polymeric components 32 of the glue 24. Accordingly, the glue 24 adheres more firmly to the roughened surface. This provides additional resistance against physical stress along cavity axis 30.

(12) FIG. 3 shows a cross-sectional view at the glue zone 22 of a second embodiment of a cylindrical rod for aerosol-generating articles 10 of the invention. In the glue zone 22, glue 24 is applied between the inner layer 18 of the wrapper 14 and the outer layer 20 of the wrapper 14, by which the overlapping edge portions of the wrapper 14 are adhered to each other.

(13) In the embodiment of FIG. 3 the outer layer 20 does not comprise any cavities 26. The cavity 26 shown in FIG. 3 penetrates completely through the inner layer 18 so as to define a cylindrical through-hole 26 in the wrapper 14. Roughening of the surface is not depicted in FIG. 3.

(14) The diameter of the cylindrical through-hole 26 is smaller than the thickness of the wrapper 14. Accordingly, the surface area of the wrapper 14 in the glue zone 22 which is newly created by the through-hole 26 exceeds the surface area of the wrapper 14 which has been removed by the creation of the through-hole 26. Thereby, the total glued surface area of the wrapper 14 is increased by the presence of the through-hole 26, even without taking into account any effect of roughening of the surface. Thus, adhesion is improved.

(15) Moreover, the glue 24 penetrates completely through the through-hole 26 such that the glue 24 adheres the rod component 12 to the wrapper 14. Thus, the through-hole 26 additionally increases adhesion between the rod component 12 and the wrapper 14. Hence, the overall adhesion is increased.

(16) In the embodiment of FIG. 3 the wrapper 14 is a tipping paper 14 and the rod component 12 is a filter plug 12. Due to the increased adhesion between the tipping paper 14 and the filter plug 12 via through-hole 26 it is less likely for the filter plug 12 to fall out of the tipping paper 14.

(17) FIG. 4 shows a cross-sectional view at the glue zone 22 of a third embodiment of a cylindrical rod for aerosol-generating articles 10 of the invention. In the embodiment of FIG. 4 both the inner layer 18 of the wrapper 14 and the outer layer 20 of the wrapper 14 comprise cavities 26. The cavity 26 of the inner layer 18 penetrates completely through the wrapper 14 so as to define a through-hole 26 in the wrapper 14. The cavity 26 of the outer layer 20 is a recess. Both cavities 26 have a roughened surface. The roughening is caused by the wrapper fibres 28. The roughened surfaces provide additional anchorages for polymeric components 32 of the glue 24. Accordingly, the glue 24 is more firmly adhered to both the inner layer 18 and the outer layer 20. Thus, the inner layer 18 and the outer layer 20 are more firmly adhered to one another. Thereby, the resistance against physical stress along cavity axis 30 is improved.

(18) The opposing cavities 26 shown in FIG. 4 are aligned with respect to cavity axis 30. However, in some embodiments in accordance to the invention the relative position of opposing cavities 26 with respect to the cavity axis 30 is arbitrary.