Thermally conducting rods for use in aerosol-generating articles

Abstract

A rod is provided, formed from a first sheet including an aerosol-forming material and a second sheet including a thermally-conductive material, the first and second sheets being gathered together and circumscribed by a wrapper. The rod may be used as a component part of an aerosol-generating article.

Claims

1. A rod, comprising: a first sheet comprising an aerosol-forming material; and a second sheet gathered together with the first sheet, the second sheet overlaying the first sheet and comprising a thermally-conductive material; and a wrapper circumscribing a gathered combination of the first and the second sheets, wherein the gathered combination of the first and the second sheets extends along substantially an entire length of the rod and across substantially an entire transverse cross-sectional area of the rod, wherein the second sheet comprising the thermally-conductive material is interwoven with the first sheet comprising the aerosol-forming material, and wherein the thermally-conductive material is configured to conduct heat throughout the rod.

2. The rod according to claim 1 in which the aerosol-forming material comprises tobacco.

3. The rod according to claim 1 in which the first sheet is a sheet of homogenised tobacco material.

4. The rod according to claim 1 in which the thermally-conductive material comprises at least one material selected from the group consisting of carbon and metal.

5. The rod according to claim 4 in which the second sheet is an aluminium foil.

6. The rod according to claim 1 in which the first sheet is crimped.

7. The rod according to claim 1 further comprising one or more additional sheets of material gathered together with the first and second sheets and circumscribed by the wrapper.

8. An aerosol-forming substrate for a heated aerosol-generating article comprising a rod comprising: a first sheet comprising an aerosol-forming material; and a second sheet gathered together with the first sheet, the second sheet overlaying the first sheet and comprising a thermally-conductive material; and a wrapper circumscribing a gathered combination of the first and the second sheets, wherein the gathered combination of the first and the second sheets extends along substantially an entire length of the rod and across substantially an entire transverse cross-sectional area of the rod, wherein the second sheet comprising the thermally-conductive material is interwoven with the first sheet comprising the aerosol-forming material, and wherein the thermally-conductive material is configured to conduct heat throughout the rod.

9. A system comprising an electrically-operated aerosol-generating apparatus and an aerosol-generating article for use with the apparatus, the aerosol-generating article comprising an aerosol-forming substrate for a heated aerosol-generating article comprising a rod comprising: a first sheet comprising an aerosol-forming material; and a second sheet gathered together with the first sheet, the second sheet overlaying the first sheet and comprising a thermally-conductive material; and a wrapper circumscribing a gathered combination of the first and the second sheets, wherein the gathered combination of the first and the second sheets extends along substantially an entire length of the rod and across substantially an entire transverse cross-sectional area of the rod, wherein the second sheet comprising the thermally-conductive material is interwoven with the first sheet comprising the aerosol-forming material, and wherein the thermally-conductive material is configured to conduct heat throughout the rod.

10. A heated aerosol-generating article comprising a combustible heat source and an aerosol-forming substrate for a heated aerosol-generating article comprising a rod comprising: a first sheet comprising an aerosol-forming material; and a second sheet gathered together with the first sheet, the second sheet overlaying the first sheet and comprising a thermally-conductive material; and a wrapper circumscribing a gathered combination of the first and the second sheets, wherein the gathered combination of the first and the second sheets extends along substantially an entire length of the rod and across substantially an entire transverse cross-sectional area of the rod, wherein the second sheet comprising the thermally-conductive material is interwoven with the first sheet comprising the aerosol-forming material, and wherein the thermally-conductive material is configured to conduct heat throughout the rod.

11. A heated aerosol-generating article for use in an electrically heated aerosol-generating system comprising an aerosol-forming substrate for a heated aerosol-generating article comprising a rod comprising: a first sheet comprising an aerosol-forming material; and a second sheet gathered together with the first sheet, the second sheet overlaying the first sheet and comprising a thermally-conductive material; and a wrapper circumscribing a gathered combination of the first and the second sheets, wherein the gathered combination of the first and the second sheets extends along substantially an entire length of the rod and across substantially an entire transverse cross-sectional area of the rod, wherein the second sheet comprising the thermally-conductive material is interwoven with the first sheet comprising the aerosol-forming material, and wherein the thermally-conductive material is configured to conduct heat throughout the rod.

Description

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

(2) FIG. 1 shows a schematic cross-section of apparatus for forming a rod according to a specific embodiment;

(3) FIG. 2 shows a schematic cross-section of apparatus for forming a rod according to a specific embodiment;

(4) FIG. 3 illustrates an embodiment of an aerosol-generating device that incorporate rods formed as described herein; and

(5) FIG. 4 illustrates an aerosol-generating system comprising an electrically-operated aerosol-generating device and an aerosol-generating article as illustrated in FIG. 3.

(6) The apparatus shown in FIG. 1 generally comprises: supply means for providing a continuous sheet of homogenised tobacco material; supply means for providing a continuous sheet of aluminium foil material; crimping means for crimping the continuous sheet of homogenised tobacco material; rod forming means for gathering the continuous crimped sheet of homogenised tobacco material together with the continuous sheet of aluminium foil material and circumscribing the gathered material with a wrapper to form a continuous rod; and cutting means for severing the continuous rod into a plurality of discrete rods. The apparatus also comprises transport means for transporting the continuous sheet of homogenised tobacco material downstream through the apparatus from the supply means to the rod forming means via the crimping means.

(7) As shown in FIG. 1, the supply means for providing a continuous sheet of homogenised tobacco material comprises a continuous sheet of homogenised tobacco material 2 mounted on a first bobbin 4. The supply means for providing a continuous sheet of aluminium foil material comprises a continuous sheet of aluminium foil 3 mounted on a second bobbin 5. The crimping means comprises a pair of rotatable crimping rollers 6. In use, the continuous sheet of homogenised tobacco material 2 is drawn from the first bobbin 4 and transported downstream to the pair of crimping rollers 6 by the transport mechanism via a series of guide and tensioning rollers. As the continuous sheet of homogenised tobacco material 2 is fed between the pair of crimping rollers 6, the crimping rollers engage and crimp the continuous sheet of homogenised tobacco material 2 to form a continuous crimped sheet of homogenised tobacco material 8 having a plurality of spaced-apart ridges or corrugations substantially parallel to the longitudinal axis of the sheet of homogenised tobacco material through the apparatus.

(8) The continuous crimped sheet of homogenised tobacco material 8 is transported downstream from the pair of crimping rollers 6 towards the rod forming means. The continuous sheet of aluminium foil material 3 is transported from the second bobbin 5 towards the rod forming means. Both the continuous sheet of aluminium foil material 3 and the continuous sheet of crimped homogenised tobacco material 8 are simultaneously fed through a converging funnel or horn 10. The converging funnel 10 gathers the continuous sheets of material 8, 3 transversely relative to their longitudinal axes. The continuous sheets of material 8,3 assume a substantially cylindrical configuration as they pass through the converging funnel 10.

(9) Upon exiting the converging funnel 10, the gathered sheets of homogenised tobacco material and aluminium foil material are wrapped in a continuous sheet of wrapping material 12. The continuous sheet of wrapping material is fed from a bobbin 14 and enveloped around the gathered continuous crimped sheet of homogenised tobacco material by an endless belt conveyor or garniture. As shown in FIG. 1, the rod forming means comprises an adhesive application means 16 that applies adhesive to one of the longitudinal edges of the continuous sheet of wrapping material, so that when the opposed longitudinal edges of the continuous sheet of wrapping material are brought into contact they adhere to one other to form a continuous rod.

(10) The rod forming means further comprises a drying means 18 downstream of the adhesive application means 16, which in use dries the adhesive applied to the seam of the continuous rod as the continuous rod is transported downstream from the rod forming means to the cutting means.

(11) The cutting means comprises a rotary cutter 20 that severs the continuous rod into a plurality of discrete rods of unit rod length or multiple unit rod length.

(12) As the two continuous sheets of material are fed into the converging funnel while overlaid, one sheet on top of the other, the rod has an even distribution of tobacco material and aluminium along the rod length.

(13) In an alternative configuration illustrated in FIG. 2, a continuous sheet of aluminium foil material 3 is positioned in overlapping relationship with a continuous sheet of homogenised tobacco material 2 upstream of a pair of crimping rollers 6. The apparatus is otherwise substantially as described above in relation to FIG. 1.

(14) Both continuous sheets of material 2,3 pass through the crimping rollers 6 in overlapping relationship and are simultaneously crimped. A crimped pair of continuous sheets 9 passes out of the crimping rollers 6 and downstream into the converging funnel 10 to be formed into a rod.

(15) FIG. 3 illustrates an embodiment of an aerosol-generating article 1000 comprising a rod as described herein. The article 1000 comprises four elements; an aerosol-forming substrate 1020, a hollow cellulose acetate tube 1030, a spacer element 1040, and a mouthpiece filter 1050. These four elements are arranged sequentially and in coaxial alignment and are assembled by a cigarette paper 1060 to form the aerosol-generating article 1000. The article 1000 has a mouth-end 1012, which a user inserts into his or her mouth during use, and a distal end 1013 located at the opposite end of the article to the mouth end 1012. The embodiment of an aerosol-generating article illustrated in FIG. 3 is particularly suitable for use with an electrically-operated aerosol-generating device comprising a heater for heating the aerosol-forming substrate.

(16) When assembled, the article 1000 is about 45 millimetres in length and has an outer diameter of about 7.2 millimetres and an inner diameter of about 6.9 millimetres.

(17) The aerosol-forming substrate 1020 comprises a rod formed from a first sheet of crimped cast-leaf tobacco and a second sheet of aluminium foil wrapped in a filter paper (not shown) to form a plug.

(18) An aerosol-generating article 1000 as illustrated in FIG. 3 is designed to engage with an aerosol-generating device in order to be consumed. Such an aerosol-generating device includes means for heating the aerosol-forming substrate 1020 to a sufficient temperature to form an aerosol. Typically, the aerosol-generating device may comprise a heating element that surrounds the aerosol-generating article 1000 adjacent to the aerosol-forming substrate 1020, or a heating element that is inserted into the aerosol-forming substrate 1020.

(19) Once engaged with an aerosol-generating device, a user draws on the mouth-end 1012 of the smoking article 1000 and the aerosol-forming substrate 1020 is heated to a temperature of about 375 degrees Celsius. At this temperature, volatile compounds are evolved from the sheet of cast-leaf tobacco of the aerosol-forming substrate 1020. These compounds condense to form an aerosol. The aerosol is drawn through the filter 1050 and into the user's mouth.

(20) FIG. 4 illustrates a portion of an electrically-operated aerosol-generating system 2000 that utilises a heating blade 2100 to heat an aerosol-generating substrate 1020 of an aerosol-generating article 1000. The heating blade is mounted within an aerosol article receiving chamber of an electrically-operated aerosol-generating device 2010. The aerosol-generating device defines a plurality of air holes 2050 for allowing air to flow to the aerosol-generating article 1000. Air flow is indicated by arrows on FIG. 4. The aerosol-generating device comprises a power supply and electronics, which are not illustrated in FIG. 4. The aerosol-generating article 1000 of FIG. 4 is as described in relation to FIG. 3.

EXAMPLE 1

(21) Rods according to a first specific embodiment comprising a crimped sheet of homogenised tobacco material gathered together with an un-crimped sheet of aluminium foil, circumscribed by a paper wrapper and having a rod length of 12 mm and diameters of between 6.9 mm and 7.2 mm were produced at rates of between 20 m/min and 25 m/min using apparatus of the type shown in FIG. 1.

(22) The continuous sheets of homogenised tobacco material were produced by a casting process, the sheets having a width of between 110 mm and 134 mm, a thickness of 120 m to 260 m, a grammage of between 167 g/m.sup.2 and 201 g/m.sup.2 and a moisture content of between 5% and 12%.

(23) The continuous sheets of aluminium foil material were produced by a rolling process. The sheets used were of the same width as the sheets of homogenised tobacco material and had a thickness of 25 m.

(24) The exemplary embodiments and example described above are not limiting. In view of the above-discussed exemplary embodiments, other embodiments consistent with the above exemplary embodiment will now be apparent to one of ordinary skill in the art.