Abstract
The present invention relates to an aerosol-generating article (10) for use with an aerosol-generating device comprising a heating element, or with an integral heat source, the aerosol-generating article (10) comprising an aerosol-forming substrate (20), a substantially incombustible wrapper (3) circumscribing the aerosol-forming substrate (20) and comprising inner and outer surfaces, wherein the inner surface of the wrapper (3) has an at least partially textured surface (5) configured to overlap a portion of the outer surface (4) of the wrapper (3) when the wrapper (3) is wrapped around the aerosol-forming substrate (20). The invention further relates to an apparatus and a method for forming an aerosol-generating article (10).
Claims
1-15. (canceled)
16. An aerosol-generating article for use with an aerosol-generating device comprising a heating element, the aerosol-generating article comprising: an aerosol-forming substrate; a substantially incombustible wrapper circumscribing the aerosol-forming substrate and comprising inner and outer surfaces; wherein the inner surface of the wrapper has an at least partially textured surface configured to overlap a portion of the outer surface of the wrapper when the wrapper is wrapped around the aerosol-forming substrate, and wherein the at least partially textured surface extends partially around the circumference of the aerosol forming substrate.
17. An aerosol-generating article comprising: an aerosol-forming substrate comprising one or more of tobacco and a source of nicotine; a heating element at the upstream end of the aerosol-forming substrate and being arranged to heat the aerosol-forming substrate so as to form an aerosol when actuated; a substantially incombustible wrapper circumscribing the aerosol-forming substrate and at least a portion of the heating element, the wrapper comprising inner and outer surfaces; wherein the inner surface of the wrapper has an at least partially textured surface configured to overlap a portion of the outer surface of the wrapper when the wrapper is wrapped around the aerosol-forming substrate, and wherein the at least partially textured surface extends partially around the circumference of the aerosol forming substrate.
18. An aerosol-generating article according to claim 16, wherein the at least partially textured surface is embossed.
19. An aerosol-generating article according to claim 16, wherein the textured portion is between about 10 millimetres and about 20 millimetres wide.
20. An aerosol-generating article according to claim 16, wherein the textured surface is between 0.5 millimetres and 10 millimetres wide; or between 1 millimetre and 8 millimetres wide; or between 1 millimetre and 6 millimetres wide; or between 1 millimetre and 5 millimetres wide; or between 2 millimetres and 5 millimetres wide.
21. An aerosol-generating article according to claim 16, wherein at least the inner surface of the wrapper is metallic.
22. An aerosol-generating article according to claim 21, wherein the textured portion of the metallic inner surface is adhesively joined to the outer surface of the opposite edge of the wrapper.
23. An aerosol-generating article according to claim 16, wherein the wrapper comprises two layers, an innermost layer being the wrapper and an outer layer circumscribing the innermost layer.
24. An aerosol-generating article according to claim 16, wherein the wrapper extends over at least a portion of the length of the aerosol-forming substrate.
25. An aerosol-generating article according to claim 16, wherein the aerosol-forming substrate comprises tobacco.
26. An aerosol-generating article according to claim 16, wherein the aerosol-forming substrate comprises a source of nicotine.
27. Apparatus for forming an embossed wrapper for circumscribing an aerosol-forming substrate, the apparatus comprising a pair of nip rollers, one of the rollers in the pair being an embossing roller comprising a profiled surface for creating an embossed pattern and the other one of the rollers in the pair being a smooth surfaced roller, the pair of rollers being configured to receive a web of substantially incombustible wrapper material between the embossing roller and the smooth surfaced roller, the embossing roller being configured to form a textured pattern in a portion of the width of the web of substantially incombustible wrapper material as it passes between the pair of rollers.
28. A method of forming an embossed wrapper for circumscribing an aerosol-forming substrate of a heated smoking article, the method comprising passing a web of substantially incombustible wrapper material through a pair of nip rollers, one of the rollers in the pair being an embossing roller comprising a profiled surface across a transverse portion of its surface and the other one of the rollers in the pair being a smooth surfaced roller, deforming one side of the web of incombustible material across a portion of its width to create a textured surface, locating an aerosol-forming substrate on the side of incombustible material comprising the textured surface and wrapping the web of incombustible material around the aerosol-forming substrate and adhering the textured surface of the web of incombustible material to an outer, smooth surface of the web of incombustible material.
29. A method of forming an aerosol-generating article comprising embossing the inner surface of an substantially incombustible wrapper, forming a rod of aerosol-forming substrate on the embossed wrapper, circumscribing the aerosol-forming substrate with the embossed wrapper, applying adhesive to a portion of the embossed inner surface which portion overlaps a portion of the outer surface of the wrapper, closing the wrapper about the aerosol-forming substrate by adhering the overlapping portion of the embossed inner surface to the outer surface of the wrapper.
30. An aerosol-generating article according to claim 17, wherein the at least partially textured surface is embossed.
Description
[0125] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
[0126] FIGS. 1a to 1e are schematic cross-sectional diagrams of an embodiment of an aerosol-generating article showing the substantially incombustible wrapper being applied to the aerosol-forming substrate;
[0127] FIG. 2 is a schematic cross-sectional diagram of an embodiment of an aerosol-generating article for use with an aerosol-generating device comprising a heating element;
[0128] FIG. 3 is a schematic cross-sectional diagram of an embodiment of an aerosol-generating article comprising an integral heating element;
[0129] FIG. 4 is a schematic diagram of an embodiment of a pair of rollers (roller and counter roller) forming part of the apparatus according to the invention;
[0130] FIG. 5 is a web of substantially incombustible wrapper material having a textured profile formed by the pair of roller of FIG. 4;
[0131] FIGS. 6a and 6b show a profiled portion of an embossing roller forming part of an embodiment of the apparatus according to the present invention;
[0132] FIG. 7 is a cross-sectional view of the profiled portion of FIG. 6a along line A-A;
[0133] FIGS. 8a and 8b are exploded views of the profiled portion of FIG. 7 taken in the area denoted as C;
[0134] FIG. 9 shows an end plan view of a profiled portion of an embossing roller forming part of another embodiment of the apparatus according to the present invention;
[0135] FIG. 10 shows the profiled portion of FIG. 9 in perspective view;
[0136] FIG. 11a is a cross-sectional view of the profiled portion of FIG. 9 along line A-A;
[0137] FIG. 11b is a cross-sectional view of the profiled portion of FIG. 9 along line B-B;
[0138] FIG. 12a is an exploded view of the profiled portion of FIG. 11a taken in the area denoted as C;
[0139] FIG. 12b is an exploded view of the profiled portion of FIG. 11b taken in the area denoted as D;
[0140] FIG. 13 shows an end plan view of a profiled portion of an embossing roller forming part of a yet further embodiment of the apparatus according to the present invention;
[0141] FIG. 14 shows an exploded view of the profiled portion of FIG. 13 taken in the area denoted as B;
[0142] FIG. 15 shows the profiled portion of FIG. 13 in perspective view;
[0143] FIG. 16 is a cross-sectional view of the profiled portion of FIG. 13 along line A-A;
[0144] FIG. 17 is an exploded view of the profiled portion of FIG. 16 taken in the area denoted as D;
[0145] FIG. 18 shows the profiled portion of FIG. 13 in plan view from above; and
[0146] FIG. 19 is an exploded view of the profiled portion of FIG. 18 taken in the area denoted as C.
[0147] Where possible, like numerals are used to depict the same features throughout the drawings.
[0148] FIGS. 1a to 1e illustrate the sequential wrapping of an aerosol-forming substrate 20 with a substantially incombustible wrapper 3. In the depicted embodiment, the substantially incombustible wrapper is formed of two layers, bonded together by a lamination process, to form the wrapper 3. The outer layer is a paper plug wrap of basis weight 45 grams per square metre (gsm.sup.−1) and 65 micrometres (μm) thickness. The inner layer is an aluminium foil of basis weight 17 grams per square metre (gsm.sup.−1) and 6.3 micrometres (μm) thickness. The substantially incombustible wrapper has a total thickness of 71.3 micrometres (μm). As shown in FIG. 1a, the aerosol-forming substrate 20 is delivered, in a direction A, onto an open web of wrapper material on a conveyor or garniture 13. The web of wrapper material 3 is delivered from a pair of rollers (not shown) in which an embossing roller has textured the inner surface of the wrapper to form an embossed portion 5. The embossed portion 5 extends partially across the transverse width of the wrapper 3. The longitudinal dimension of the wrapper 3 is perpendicular to the plane of the drawing. In FIG. 1b, one edge of the substantially incombustible wrapper is folded in the direction B onto the aerosol-forming substrate 20. At FIG. 1c, adhesive is applied by a glue applicator 11 to the embossed portion 5 on the inner surface of the opposite edge of the substantially incombustible wrapper 3. The embossed portion 5 is folded in a direction C onto a portion 4 of the outer paper surface of the substantially incombustible wrapper 3 in FIG. 1d. The embossed portion 5 of the inner surface of the aluminium foil layer is now in contact with the portion 4 of the paper outer layer of substantially incombustible wrapper 3.
[0149] As seen in FIG. 1e, vertical pressure is exerted in direction D directly on the substantially incombustible wrapper 3 to ensure adhesion between the embossed portion 5 of the aluminium foil layer to the portion 4 of the paper layer of the substantially incombustible wrapper 3. The embossed portion 5 ensures the non-porous aluminium foil has sufficient surface area for successful adhesion between the aluminium foil and the paper outer of the substantially incombustible wrapper 3 in the area of the lap seam between wrapper portions 5 and 4. Without the embossed portion 5, the metallic aluminium foil layer of the substantially incombustible wrapper 3, which is the inner surface that is glued then pressed on the outside paper surface, is not porous, creating problems with the gluing of the wrapper material. In such arrangements, the aluminium layer of the wrapper is not porous enough to absorb the glue, therefore resulting in a weak glue seam on the aerosol-generating article exiting the tobacco crimper machine. Due to the weak glue seam between the metallic aluminium foil layer of the wrapper and the paper layer, the crimper machine and combiner machine handling the formation of the aerosol-generating article could experience a reduction in performance. For example both of the combiner and the crimper may experience increased downtime and waste to remove defective product resulting in potentially large volume losses. The substantially incombustible wrapper 3 of the invention mitigates the potential losses experienced in products with a weak glue seam in the wrapper.
[0150] As shown in FIG. 1e, the aerosol-forming substrate 20, is wrapped in a substantially incombustible wrapper 3 formed of a metallic, heat conducting layer in contact with the aerosol-forming substrate 20 and a paper plug wrap outer layer. The layers may be bonded together in a lamination process to form the substantially incombustible wrapper 3.
[0151] The inner aluminium layer is the inside layer in contact with the aerosol-forming substrate 20. This layer has a heat conducting function. Alternatively, or in addition, the inner aluminium layer may prevent product lighting when extending over an integral heat source.
[0152] The outer layer of the substantially incombustible wrapper 3 is made of paper. Because this layer is on the outside, it is important that the visual aspect and qualitative look of this layer are of a high standard. The partial thickness of the embossing of the inner layer of the substantially incombustible wrapper 3 means that the appearance of the paper outer layer is not altered by the embossing pattern.
[0153] FIG. 2 illustrates an aerosol-generating article 10 according to an embodiment of the invention. The aerosol-generating article 10 comprises four elements arranged in coaxial alignment: an aerosol-forming substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. These four elements are arranged sequentially and are circumscribed by an outer wrapper 60 to form the aerosol-generating article 10. The aerosol-generating 10 has a proximal or mouth end 70, which a user inserts into his or her mouth during use, and a distal end 80 located at the opposite end of the aerosol-generating article 10 to the mouth end 70.
[0154] In use air is drawn through the aerosol-generating article by a user from the distal end 80 to the mouth end 70. The distal end 80 of the aerosol-generating article may also be described as the upstream end of the aerosol-generating article 10 and the mouth end 70 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the mouth end 70 and the distal end 80 can be described as being upstream of the mouth end 70 or, alternatively, downstream of the distal end 80.
[0155] The aerosol-forming substrate 20 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in FIG. 2, aerosol-forming substrate 20 comprises a gathered sheet of crimped homogenised tobacco material circumscribed by a substantially incombustible wrapper 3. The crimped sheet of homogenised tobacco material comprises comprising glycerine as an aerosol-former. The substantially incombustible wrapper 3 is formed of a laminated plug wrap having a paper outer layer and an aluminium inner layer. The inner aluminium layer is embossed (textured) across a portion of its traverse width so as to provide an embossed region of the inner layer that will overlap a portion of the paper outer layer when the substantially incombustible wrapper 3 circumscribes the aerosol-forming substrate 20. The aluminium inner layer is impervious to the applied adhesive. By texturing the inner surface of the aluminium inner layer, the adhesion of the inner layer to the paper outer layer is increased. This increased adhesion prevents the gaping, or partial opening, of the lap seam between the edges of the substantially incombustible wrapper 3 during the assembly of the aerosol-generating article 10.
[0156] The support element 30 is located immediately downstream of the aerosol-forming substrate 20 and abuts the aerosol-forming substrate 20. In the embodiment shown in FIG. 2, the support element is a hollow cellulose acetate tube. The support element 30 locates the aerosol-forming substrate 20 at the extreme distal end 80 of the aerosol-generating article 10 so that it can be penetrated by a heating element of an aerosol-generating device. The support element 30 acts to prevent the aerosol-forming substrate 20 from being forced downstream within the aerosol-generating article 10 towards the aerosol-cooling element 40 when a heating element of an aerosol-generating device is inserted into the aerosol-forming substrate 20. The support element 30 also acts as a spacer to space the aerosol-cooling element 40 of the aerosol-generating article 10 from the aerosol-forming substrate 20.
[0157] The aerosol-cooling element 40 is located immediately downstream of the support element 30 and abuts the support element 30. In use, volatile substances released from the aerosol-forming substrate 20 pass along the aerosol-cooling element 40 towards the mouth end 70 of the aerosol-generating article 10. The volatile substances may cool within the aerosol-cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 2, the aerosol-cooling element comprises a crimped and gathered sheet of polylactic acid circumscribed by a wrapper 90. The crimped and gathered sheet of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol-cooling element 40.
[0158] The mouthpiece 50 is located immediately downstream of the aerosol-cooling element 40 and abuts the aerosol-cooling element 40. In the embodiment illustrated in FIG. 2, the mouthpiece 50 comprises a conventional cellulose acetate tow filter of low filtration efficiency.
[0159] To assemble the aerosol-generating article 10, initially the aerosol-forming substrate 20 may be wrapped within substantially incombustible wrapper 3 in accordance with the steps shown in FIG. 1. The four elements described above, including the wrapped aerosol-forming substrate 20, are then aligned and tightly wrapped within the outer wrapper 60. In the embodiment illustrated in FIG. 2, the outer wrapper is a conventional cigarette paper. As shown in FIG. 2, an optional row of perforations is provided in a region of the outer wrapper 60 circumscribing the support element 30 of the aerosol-generating article 10.
[0160] In the embodiment illustrated in FIG. 2, a distal end portion of the outer wrapper 60 of the aerosol-generating article 10 is circumscribed by a band of tipping paper (not shown).
[0161] The aerosol-generating article 10 illustrated in FIG. 2 is designed to engage with an aerosol-generating device comprising a heating element in order to be smoked or consumed by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 20 of the aerosol-generating article 10 to a sufficient temperature to form an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user.
[0162] FIG. 3 illustrates an aerosol-generating article 100 according to an embodiment of the invention. The aerosol-generating article 100 comprises five elements arranged in coaxial alignment: an integral heat source 25, an aerosol-forming substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. These five elements are arranged sequentially and are circumscribed by an outer wrapper 60 to form the aerosol-generating article 10. The aerosol-generating article 100 illustrated in FIG. 3 differs from the aerosol-generating article 10 of FIG. 2 in that it comprises an integral heat source 25 at the distal end of the aerosol-forming substrate 20 and which abuts the aerosol-forming substrate 20. Substantially incombustible wrapper 3 circumscribes the aerosol-forming substrate 20 and the entire length of the integral heat source 25 in this embodiment. By covering the integral heat source 25, which is a carbon heat source 25, the substantially incombustible wrapper 3 prevents lighting of the integral heat source. The wrapper 3 may need to be partially removed from the heat source 25 before ignition or actuation.
[0163] The aerosol-generating article 100 illustrated in FIG. 3 is designed to have a user ignite the integral heat source 25 in order for the article to be smoked or consumed by a user. In use, the integral heat source 25 heats the aerosol-forming substrate 20 of the aerosol-generating article 100 to a sufficient temperature to form an aerosol, which is drawn downstream through the aerosol-generating article 100 and inhaled by the user.
[0164] FIG. 4 shows a pair of rollers (roller and counter roller) forming part of the apparatus according to the invention. The pair of rollers comprises an embossing roller 27 having an embossing surface portion 26 and a smooth surface portion 28. Only a part of the embossing roller surface comprises embossing teeth 31. In use, the embossing roller 27 will contact the inner aluminium foil layer of the wrapper material (not shown), and the embossing surface portion 26, comprising teeth 31, covers the area of the inner layer of the substantially incombustible wrapper that will overlap the outer surface of the wrapper material when the adhesive is applied and the two portions overlapped as shown in FIGS. 1a to 1e. The counter roller, that is the smooth surface roller 29, will be in contact with the outer layer of the wrapper material. The smooth surface roller 29 ensures that the outer layer of the substantially incombustible wrapper will not be altered by the embossing process.
[0165] Each of the pair of rollers 27, 29 is mounted onto a shaft 33a, 33b which is mountable onto a crimper machine (not shown) downstream of the aerosol-forming substrate crimper (not shown). The shafts 33a, 33b of the rollers may be free moving or motorized. If the shafts are free moving, the rollers are easy to install.
[0166] An endless screw (not shown) may be provided, which is operated by an operator using a handle and which allows adjustment of the distance between the embossing roller 27 and the smooth surface roller 29. Adjusting the distance between the surfaces of the rollers 27, 29 changes the depth of the embossing on the inner surface of the substantially incombustible wrapper 3 passed between the rollers 27, 29.
[0167] FIG. 5 illustrates the inner surface of a web of substantially incombustible wrapper 3 following processing through the pair of rollers of FIG. 4. The embossed portion 5 extends along the full length of the web and partially across the transverse width of the web of substantially incombustible wrapper. The smooth portion 2 of the inner surface of the web of substantially incombustible wrapper 3 remains smooth. In this way, the smooth portion of the inner surface of the substantially incombustible wrapper 3 will form an intimate contact with the rod of aerosol-forming substrate when the wrapper 3 circumscribes the rod of aerosol-forming substrate.
[0168] FIGS. 6a to 8b depict a profiled portion of an embossing roller forming part of the apparatus according to the present invention. FIGS. 9 to 12b depict an alternative profiled portion of an embossing roller forming part of the apparatus according to the present invention. FIGS. 13 to 19 depict a further alternative profiled portion of an embossing roller forming part of the apparatus according to the present invention. Similar features in each embodiment of the embossing roller are denoted by similar reference numerals, increased by a factor of 100.
[0169] FIG. 6a is an end plan view of a profiled portion 26 of the embossing roller 27. FIG. 6b is a perspective view of the profiled portion 26. Referring to FIG. 6a, the surface of the profiled portion 26 comprises a plurality of teeth 31 with adjacent teeth 31 separated by recesses 39 around the entire circumference of the embossing roller 27. 45 teeth are arranged around the circumference of the embossing roller 27 with each tooth occupying a circumferential angle of 8 degrees measured from the longitudinal axis of the roller 27 including centre point 41 of the hollow core 35 of the embossing roller. The diameter of the embossing roller 27 measured to the points of the teeth is 30 millimetres. The diameter of the embossing roller 27 measured to the bottom of recesses 39 is 28 millimetres. In the embodiment depicted in FIGS. 6a to 8, the teeth 31 are 2 millimetres in height from the base of the adjacent recess 39 to the point of the tooth 31.
[0170] FIG. 6b shows the profiled portion 26 of teeth shown in FIG. 6a extending transversely across the width of the profiled portion 26. It will be understood that only the profiled portion 26 of the embossing roller is shown in the embodiment and the smooth surface of the remaining transverse width of the embossing roller 27 is not shown. The hollow core 35 allows the embossing roller 27 to fit onto a shaft (see 33a, 33b in FIG. 4) and locating flange 37 ensures the shaft and the roller 27 rotate together.
[0171] FIG. 7 is a cross-sectional view of the profiled portion 26 of embossing roller 27 of FIG. 6a along line A-A. The hollow core 35 has a diameter of 26 millimetres excluding locating flange 37. The teeth 31 and adjacent recesses 39 extends across the width of profiled portion 26.
[0172] FIGS. 8a and 8b are exploded views of the profiled portion of FIG. 7 taken in the area denoted as C. Each tooth 31 has a first face 41 and a second face 43 joining at the base of a recess 39. The first face 41 of a first tooth 31a and the second face 43 of an adjacent second tooth 31b are at an angle α of 90 degrees to one another in the depicted embodiment.
[0173] FIG. 9 shows an end plan view of a profiled portion 126 of an embossing roller 127 forming part of the apparatus according to the present invention. FIG. 9 is an end plan view of a profiled portion 126 of the embossing roller 127. FIG. 10 is a perspective view of the profiled portion 126. Referring to FIG. 9, the surface of the profiled portion 126 comprises a plurality of teeth 131 with adjacent teeth 131 separated by recesses 139 around the entire circumference of the embossing roller 127. Each tooth 131 has a flattened point (tip). 18 teeth 131 are arranged around the circumference of the embossing roller 127 with each tooth occupying a circumferential angle of 20 degrees measured from the longitudinal axis of the roller 127 including centre point 141 of the hollow core 135 of the embossing roller. The diameter of the embossing roller 127 measured to the flattened point of the teeth is 30 millimetres. The diameter of the embossing roller 127 measured to the bottom of recesses 139 is 28 millimetres. In the embodiment depicted in FIGS. 9 to 12b, the teeth 131 are 2 millimetres in height from the base of the adjacent recess 139 to the flattened point of the tooth 131.
[0174] FIG. 10 shows the profiled portion 126 of teeth shown in FIG. 9 extending transversely across the width of the profiled portion 126. It will be understood that only the profiled portion 126 of the embossing roller is shown in the embodiment and the smooth surface of the remaining transverse width of the embossing roller 127 is not shown. The hollow core 135 allows the embossing roller 127 to fit onto a shaft (see 33a, 33b in FIG. 4) and locating flange 137 ensures the shaft and the roller 27 rotate together.
[0175] FIG. 11a is a cross-sectional view of the profiled portion 126 of embossing roller 127 of FIG. 9 taken along line A-A and FIG. 11b is a cross-sectional view of the profiled portion 126 of embossing roller 127 of FIG. 9 taken along line B-B. The hollow core 135 has a diameter of 26 millimetres excluding locating flange 137. The teeth 131 and adjacent recesses 139 extend across the width of profiled portion 126.
[0176] FIG. 12a is an exploded view of the profiled portion of FIG. 11a taken in the area denoted as C. Each tooth 131 has a first face 141 and a second face 143 joining at the base of a recess 139. As illustrated in FIG. 12b, which is an exploded view of the profiled portion of FIG. 11b taken in the area denoted as D, the first face 141 of a first tooth 131a and the second face 143 of an adjacent second tooth 131b are at an angle β of 90 degrees to one another in the depicted embodiment.
[0177] FIG. 13 shows an end plan view of a profiled portion 226 of an embossing roller 227 forming part of a yet further embodiment of the apparatus according to the present invention.
[0178] FIG. 13 is an end plan view of a profiled portion 226 of the embossing roller 227. The surface of the profiled portion 226 comprises a plurality of teeth 231 with adjacent teeth 231 separated by recesses 239 around the entire circumference of the embossing roller 227. As best shown in FIG. 19, each tooth 231 has a tip offset from the longitudinal axis of the profiled portion 226 which axis includes centre point 241. The angle of offset γ is 45 degrees in the depicted embodiment. In this way, the tip of each tooth 231 has both a transverse and a circumferential dimension. FIG. 19 also depicts rows of teeth extending across the transverse width of the profiled portion 226. The rows of teeth, 2310, 2311, 2312, 2313, 2314, 2315, 2316, 2317 are 3 millimetres in dimension when measured along the tip of each tooth 231. The tips of the teeth 231 in each adjacent row are at an angle α′ of 90 degrees to one another.
[0179] FIG. 13 shows 90 teeth 231 arranged in a row around the circumference of the embossing roller 227 with each tooth occupying a circumferential angle of 4 degrees measured from the longitudinal axis of the roller 227 including centre point 241 of the hollow core 235 of the embossing roller. The diameter of the embossing roller 227 measured to the point of the teeth is 30 millimetres. The diameter of the embossing roller 227 measured to the bottom of recesses 239 is 29 millimetres. In the embodiment depicted in FIGS. 13 to 19, the teeth 231 are 1 millimetre in height from the base of the adjacent recess 239 to the point of the tooth 231.
[0180] FIG. 15 shows the profiled portion 226 comprising rows of teeth 231 extending transversely across the width of the profiled portion 226. It will be understood that only the profiled portion 226 of the embossing roller is shown in the embodiment and the smooth surface of the remaining transverse width of the embossing roller 227 is not shown. The hollow core 235 allows the embossing roller 227 to fit onto a shaft (see 33a, 33b in FIG. 4) and locating flange 237 shown in FIG. 16 ensures the shaft and the roller 227 rotate together.
[0181] FIG. 16 is a cross-sectional view of the profiled portion 226 of embossing roller 227 of FIG. 13 taken along line A-A. The hollow core 235 has a diameter of 26 millimetres excluding locating flange 237. The teeth 231 and adjacent recesses 239 extend across the width of profiled portion 226.
[0182] FIG. 17 is an exploded view of the profiled portion 226 of FIG. 16 taken in the area denoted as D. Each tooth 231 has a first face 241 and a second face 243 joining at the base of a recess 239. The first face 243 of a first tooth 231a and the second face 241 of an adjacent second tooth 231b are at an angle δ of 90 degrees to one another in the depicted embodiment.
[0183] FIG. 14 is an exploded view taken at area B in FIG. 13. The profiled portion 226 comprises rows of teeth 2310 and 2311, the points of which rows of teeth are set at an angle of 90 degrees to one another.
[0184] The faces 241 and 243 of adjacent teeth, together forming recess 239, are at an angle δ to one another.
[0185] As can be seen, various profiles of teeth are envisaged. The height of each tooth is less than the thickness of the inner heat conducting layer of the substantially incombustible wrapper. In this way, the embossing roller can texture the inner surface of the substantially incombustible wrapper without affecting the outer surface of the substantially incombustible wrapper. The embossed surface does not penetrate or otherwise break through the entire thickness of the substantially incombustible wrapper. In this way, the embossed surface provides a textured surface portion on the inner layer of the substantially incombustible wrapper to improve the adhesion between overlapping layers of the substantially incombustible wrapper without affecting the quality or appearance of the outer layer.
[0186] The height of the teeth on the embossed roller may be 1 millimetre or more. The relatively larger height dimension of the teeth is possible because the outer layer of the substantially incombustible wrapper is held against the smooth surface of the counter roller and because the distance between the rollers is adjustable, so that whatever the size of the teeth, the depth of the embossing may be adjusted accordingly without affecting the quality or appearance of the outer layer.
[0187] The various embossing rollers having different teeth profiles each have a hollow core of the same diameter (between about 8 millimetres to about 36 millimetres, preferably 26 millimetres), so that they can be easily and quickly mounted on the same shaft which can be fixed on to the crimper machine. The rollers may be fixed to the shaft using a cotter pin to prevent rotation of the roller relative to the shaft.
[0188] During the process of making the aerosol-forming article of the invention, the substantially incombustible wrapper material may be closed around the aerosol-forming substrate and the overlapping edges adhered to one another using adhesive (for example glue). The gluing process may be part of a larger process which involves the crimping of the aerosol-forming substrate (by a “Crimper machine”, not shown) which inputs aerosol-forming substrate and substantially incombustible wrapper material onto the conveyor (13 in FIGS. 1a to 1e), and which outputs rods of wrapped aerosol-forming substrate. The rods of wrapped aerosol-forming substrate are then used in a “Combiner machine” which combines filters and other components to the rods of wrapped aerosol-forming substrate so as to form the final product.
[0189] The manufacturing process may proceed by folding the substantially incombustible wrapper around the longitudinal axis of a rod of aerosol-forming substrate then applying seam glue along one edge of the inner surface of the inner layer (for example the surface in contact with the aerosol-forming substrate) of the substantially incombustible wrapper and then pressing the glued area on to the top surface of the other edge of the substantially incombustible wrapper.
[0190] Using the pair of rollers shown in FIG. 4, for example, the inner layer of the substantially incombustible wrapper, that is the layer in contact with the aerosol-forming substrate and which will overlap the outside layer of the substantially incombustible wrapper following the gluing process, is embossed to create a roughened profile of the inner surface of the inner layer of the substantially incombustible wrapper. The embossing increases the contact area of the surface of the inner layer of the substantially incombustible wrapper in the region of overlap with the outer surface of the outer layer. This provides better bonding of the substantially incombustible wrapper at the seam.
[0191] During the wrapping of the aerosol-forming substrate in the substantially incombustible wrapper, a web of substantially incombustible wrapper material may be pulled by the crimper machine between the pair of rollers. The axes of the embossing and the smooth surfaced rollers of the pair of rollers may be oriented to be orthogonal to the direction of travel of the web of substantially incombustible wrapper material.
[0192] The profiled portion of the embossing roller creates a textured portion on the inner layer of the substantially incombustible wrapper in an area that will be overlapping the outer layer when the wrapper is closed about the aerosol-forming substrate, but does not necessarily cover all the inner layer surface. In this way, the smooth inner surface of the inner layer can form an intimate contact with the aerosol-forming substrate.
[0193] The height of the teeth on the embossing roller is such that the appearance of the outer layer is not changed by the embossing process. Alternatively, or in addition, the distance between the embossing roller and the smooth surfaced roller is such that the appearance of the outer layer is not changed by the embossing process.
[0194] As a result of the improved adhesion of the embossed non-porous (for example metallic) portion of the inner layer to the smooth outer layer of the substantially incombustible wrapper, the quality of the rods of wrapper aerosol-forming substrate may be improved and the volume of waste or rejected product may be reduced.
[0195] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
[0196] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
