Rods for use in smoking articles

Abstract

A rod for use in a smoking article comprises a gathered sheet of homogenised tobacco material circumscribed by a wrapper. The sheet of homogenised tobacco material may comprises one or more aerosol-formers and have an aerosol former content of greater than 5% on a dry weight basis or of between 5% and 30% by weight on a dry weight basis. The rod may comprise a continuous element to which one or more additives have been applied, which is incorporated into the gathered continuous sheet of homogenised tobacco material. A method of forming the rod comprises the steps of: providing a continuous sheet of homogenised tobacco material; gathering the continuous sheet of homogenised tobacco material transversely relative to the longitudinal axis thereof; circumscribing the gathered continuous sheet of homogenised tobacco material with a wrapper to form a continuous rod; and severing the continuous rod into a plurality of discrete rods. The sheet of homogenised tobacco material is preferably crimped or otherwise textured.

Claims

1. A method of forming a rod comprising: providing a continuous sheet of homogenized tobacco material comprising one or more aerosol-formers, wherein the sheet of homogenized tobacco material has an aerosol former content of greater than 5% on a dry weight basis; crimping the continuous sheet of homogenized tobacco material thereby forming a continuous crimped sheet having a plurality of substantially parallel ridges or corrugations; after said crimping, gathering the continuous crimped sheet of homogenized tobacco material transversely relative to the longitudinal axis thereof; circumscribing the gathered continuous sheet of homogenized tobacco material with a wrapper to form a continuous rod; and severing the continuous rod into a plurality of discrete rods, wherein the continuous sheet of homogenized tobacco material is cast leaf tobacco, wherein the plurality of substantially parallel ridges or corrugations of the continuous crimped sheet are substantially parallel to a cylindrical axis of the continuous rod, wherein the gathered continuous sheet of homogenised tobacco material extends along substantially an entire length of the continuous rod and across substantially an entire transverse cross-sectional area of the continuous rod, and wherein a width of the continuous sheet of homogenized tobacco material is at least five times a maximum transverse dimension of the continuous rod.

2. A method of forming a rod comprising: providing a continuous sheet of homogenized tobacco material comprising one or more aerosol-formers, wherein the sheet of homogenized tobacco material has an aerosol former content of between 5% and 30% by weight on a dry weight basis; crimping the continuous sheet of homogenized tobacco material, thereby forming a continuous crimped sheet having a plurality of substantially parallel ridges or corrugations; after said crimping, gathering the continuous crimped sheet of homogenized tobacco material transversely relative to the longitudinal axis thereof; circumscribing the gathered continuous sheet of homogenized tobacco material with a wrapper to form a continuous rod; and severing the continuous rod into a plurality of discrete rods, wherein the plurality of substantially parallel ridges or corrugations of the continuous crimped sheet are substantially parallel to a cylindrical axis of the continuous rod, wherein the gathered continuous sheet of homogenised tobacco material extends along substantially an entire length of the continuous rod and across substantially an entire transverse cross-sectional area of the continuous rod, and wherein a width of the continuous sheet of homogenized tobacco material is at least five times a maximum transverse dimension of the continuous rod.

3. A method of forming a rod comprising: providing a continuous sheet of homogenized tobacco material; crimping the continuous sheet of homogenized tobacco material, thereby forming a continuous crimped sheet having a plurality of substantially parallel ridges or corrugations; after said crimping, gathering the continuous crimped sheet of homogenized tobacco material transversely relative to the longitudinal axis thereof; incorporating a continuous element to which one or more additives have been applied into the gathered continuous sheet of homogenized tobacco material; circumscribing the gathered continuous sheet of homogenized tobacco material with a wrapper to form a continuous rod; and severing the continuous rod into a plurality of discrete rods, wherein the plurality of substantially parallel ridges or corrugations of the continuous crimped sheet are substantially parallel to a cylindrical axis of the continuous rod, wherein the gathered continuous sheet of homogenised tobacco material extends along substantially an entire length of the continuous rod and across substantially an entire transverse cross-sectional area of the continuous rod, and wherein a width of the continuous sheet of homogenized tobacco material is at least five times a maximum transverse dimension of the continuous rod.

4. The method according to claim 3, wherein the continuous element is impregnated with a liquid flavorant.

5. The method according to claim 3, wherein the continuous element is a thread, yarn, tape or filament.

6. The method according to claim 3, wherein the continuous element is formed from cotton, cellulose acetate or rayon.

7. The method according to claim 3, wherein the continuous element is formed from tobacco.

8. The method according to claim 1, wherein the continuous rod has a length of between 5 mm and 20 mm.

9. The method according to claim 1, wherein the width of the continuous sheet of homogenized tobacco material is at least 25 mm.

10. The method according to claim 1, wherein the continuous sheet of homogenized tobacco material has a tobacco content of 50% by weight on a dry weight basis.

11. The method according to claim 2, wherein the entire length of the continuous rod is between 5 mm and 20 mm.

12. The method according to claim 2, wherein the width of the continuous sheet of homogenized tobacco material is at least 25 mm.

13. The method according to claim 2, wherein the continuous sheet of homogenized tobacco material is cast leaf tobacco.

14. The method according to claim 2, wherein the continuous sheet of homogenized tobacco material has a tobacco content of 50% by weight on a dry weight basis.

15. The method according to claim 3, wherein entire length of the continuous rod is between 5 mm and 20 mm.

16. The method according to claim 3, wherein the width of the continuous sheet of homogenized tobacco material is at least 25 mm.

17. The method according to claim 3, wherein the continuous sheet of homogenized tobacco material is cast leaf tobacco.

18. The method according to claim 3, wherein the continuous sheet of homogenized tobacco material has a tobacco content of 50% by weight on a dry weight basis.

19. The method of forming a smoking article comprising the method for forming a continuous rod according to claim 1 and using the continuous rod as an aerosol-generating substrate in the smoking article.

20. The method according to claim 19, wherein the continuous rod is used in a filter of the smoking article.

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 schematic cross-section of apparatus for forming a rod according to the invention;

(3) FIG. 2 shows the density of rods according to a first embodiment of the invention formed using the apparatus shown in FIG. 1; and

(4) FIG. 3 shows the density of rods comprising shreds of tobacco material.

(5) The apparatus shown in FIG. 1 generally comprises: supply means for providing a continuous sheet of homogenised tobacco 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 and circumscribing the gathered continuous crimped sheet of homogenised tobacco 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.

(6) As shown in FIG. 1, the supply means comprises a continuous sheet of homogenised tobacco material 2 mounted on a bobbin 4 and 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 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.

(7) The continuous crimped sheet of homogenised tobacco material 8 is transported downstream from the pair of crimping rollers 6 to the rod forming means by the transport mechanism where it is fed through a converging funnel or horn 10. The converging funnel 10 gathers the continuous crimped sheet of homogenised tobacco material 8 transversely relative to the longitudinal axis of the sheet of homogenised tobacco material. The continuous crimped sheet of homogenised tobacco material 8 assumes a substantially cylindrical configuration as it passes through the converging funnel 10.

(8) Upon exiting the converging funnel 10, the gathered continuous crimped sheet of homogenised tobacco material is 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.

(9) 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.

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

(11) The apparatus shown in FIG. 1 further comprises an additive application means 24 located between the crimping means and the rod forming means for applying solid or liquid additives such as, for example, flavourants, to the continuous crimped sheet of homogenised tobacco material 8 before it is gathered transversely relative to the longitudinal axis thereof by the converging funnel 10.

(12) In one alternative embodiment (not shown), the additive application means is located between the supply means and the crimping means for applying solid or liquid additives to the continuous sheet of homogenised tobacco material before it is crimped.

(13) In another alternative embodiment (not shown), the additive application means is located adjacent to the converging funnel 10 of the rod forming means and is adapted to apply solid or liquid additives to the gathered continuous crimped sheet of homogenised tobacco material before it is wrapped in the continuous sheet of wrapping material 12.

(14) In a further embodiment (not shown) the apparatus further comprises means located between the crimping means and the rod forming means for incorporating a continuous element to which one or more additives have been applied into the continuous crimped sheet of homogenised tobacco material 8 as it is gathered by the converging funnel 10.

EXAMPLE 1

(15) Rods according to a first embodiment of the invention comprising a gathered crimped sheet of homogenised tobacco material circumscribed by a paper wrapper and having a length of 120 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. Continuous sheets of tobacco material produced by a casting process 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% were used to form the rods.

(16) The density of five rods according to the first embodiment of the invention was measured at positions between 10 mm and 110 mm along the length of the rods using a C.sup.2 cigarette testing unit available from Cerulean, a trading name of Molins PLC of Milton Keynes, United Kingdom. The results of the density measurements are shown in FIG. 2.

(17) For the purpose of comparison, the density of five rods of the same dimensions but comprising shreds of homogenised tobacco material circumscribed by a paper wrapper was also measured at positions between 10 mm and 110 mm along the length of the rods using standard techniques. The results of the density measurements are shown in FIG. 3.

(18) As shown in FIG. 2, for the five rods according to the first embodiment of the invention the minimum density value is about 410 mg/cm.sup.3, the maximum density value is about 450 mg/cm.sup.3 and the average density value is about 430 mg/cm.sup.3 with a standard deviation of about 9 mg/cm.sup.3 and a coefficient of variation (CV) of about 2%.

(19) As shown in FIG. 3, for the five rods comprising shreds of homogenised tobacco material the minimum density value is about 360 mg/cm.sup.3, the maximum density value is about 470 mg/cm.sup.3 and the average density value is about 410 mg/cm.sup.3 with a standard deviation of about 29 mg/cm.sup.3 and a CV of about 7%.

(20) As illustrated by the data presented in FIGS. 2 and 3, the rods according to the first embodiment of the invention advantageously exhibit more uniform densities than the rods comprising shreds of homogenised tobacco material.

EXAMPLE 2

(21) Rods according to a second embodiment of the invention having a length of 12 mm and diameters of between 6.9 mm and 7.2 mm for use as aerosol-generating substrates in electrically heated smoking articles were produced by severing the rods according to the first embodiment of the invention produced in Example 1.