WO2017198994A1

WO2017198994A1 - Filter rod having a corrugated coating and apparatus and method for filter rod manufacture

Info

Publication number: WO2017198994A1
Application number: PCT/GB2017/051043
Authority: WO
Inventors: Sam WHIFFEN; John Richardson
Original assignee: British American Tobacco (Investments) Limited
Priority date: 2016-05-19
Filing date: 2017-04-13
Publication date: 2017-11-23
Also published as: WO2017198994A8; GB201608814D0

Abstract

A filter rod for use in a tobacco industry product comprising an extruded tubular portion formed from a first filter material and having an outer surface comprising a plurality of continuous grooves extending in an axial direction of the tubular portion and defining a grooved outermost surface of the filter rod, and a continuous extruded core of second filter material provided within the tubular portion. Also provided is an apparatus and method for manufacturing such a filter rod.

Description

FILTER ROD HAVING A CORRUGATED COATING AND APPARATUS AND METHOD FOR FILTER ROD MANUFACTURE

Technical Field

In this specification there is described an apparatus and method for filter rod manufacture and, in particular, an apparatus and method for manufacture of grooved filter rods having a filled core.

Background

Apparatuses and methods for manufacture of filter rods for tobacco industry products, such as smoking articles, are known that comprise a continuous garniture belt that conveys filter tow material fed onto a continuous band of plug wrap though a tapering garniture duct or "tongue". Within the garniture tongue the garniture belt wraps the plug wrap around the filter tow material and compresses the material into a continuous cylindrical wrapped rod which can subsequently be cut to desired lengths.

Summary

In this specification there are described embodiments of a filter rod for use in a tobacco industry product comprising an extruded tubular portion formed from a first filter material and having an outer surface comprising a plurality of continuous grooves extending in an axial direction of the tubular portion and defining a grooved outermost surface of the filter rod, and a continuous extruded core of second filter material provided within the tubular element.

The first filter material may comprise cellulose acetate tow which is hardened with a plasticiser.

The filter rod may not comprise any outer wrap around the tubular portion.

The second filter material of the core may comprise cellulose acetate. The second filter material may comprise an aerosol modifying additive.

The first filter material may comprise cellulose acetate with entrained plasticiser, and the second filter material may comprises cellulose acetate with entrained plasticiser, and wherein the proportion by weight of plasticiser in the first filter material may be greater than the proportion by weight of plasticiser in the second filter material. The grooves maybe of uniform size and regularly spaced around the circumference of the filter rod. The grooves may extend continuously and without interruption around the entire circumference of the filter rod. In this specification there are also described embodiments of a filter for a tobacco industry product comprising a first filter segment formed from a filter rod as described above, and a second filter segment axially aligned with the first filter segment and joined thereto by a plug wrap around the filter rod and second filter segment. In this specification there are also described embodiments of a tobacco industry product comprising a tobacco rod and a filter formed from a filter rod or a filter as described above.

The filter may include a rotatable section, and a pawl engageable in the grooves of the filter to define discrete rotational positions of the rotatable section.

In this specification there are also described embodiments of an apparatus for manufacturing a filter rod for use in production of a tobacco industry product, the apparatus comprising a duct having an inlet configured to receive a first filter material, and an outlet, the duct tapering along at least a part of its length between the inlet and the outlet, a mandrel disposed at least partially within the duct and fixed relative to the duct, wherein the mandrel includes an internal passage extending therethough through which a second filter material may be conveyed, the passage including an outlet at a distal end of the mandrel though which the second filter material may be expelled, and a heating region configured to heat the first filter material within the duct, the apparatus configured such that the first filter material conveyed through the duct is compressed around the mandrel into a tubular portion, the second filter material fed though the internal passage of the mandrel is expelled out of the passage outlet to fill the bore of the tubular portion, and plasticiser entrained in the first filter material is at least partially cured to harden the first filter material, to produce a continuous filter rod comprising a tubular rod of hardened first filter material with a continuous core of second filter material, and wherein the duct is provided with a plurality of inwardly projecting elements to contact the tubular rod to form grooves into an outer surface of the tubular rod. The inwardly projecting elements may be provided on an inside wall of the duct.

The duct may comprise first and second sections, wherein the first section may taper from the inlet to the second section, and the second section may be of constant cross- section from the first section to the outlet, and wherein the inwardly projecting elements extend continuously in an axial direction along at least a portion of the second section.

The duct may comprise a die and the inwardly projecting elements may be formed on the die. The die may be detachable from the duct, or may be permanently attached to, or formed integrally with, the duct.

The inwardly projecting elements may be of a uniform size and are regularly spaced around the duct.

The internal passage of the hollow mandrel may include a tapered section which narrows in a direction towards the distal end of the mandrel.

A distance between an outer surface of the mandrel and an inner surface of the duct may reduce along at least a part of the length of the duct in a direction towards the distal end of the mandrel.

The distal end of the mandrel maybe positioned downstream of the outlet of the duct. The mandrel may extend entirely through the length of the duct. The distal end of the mandrel may be positioned within the duct. The mandrel may extend into the heating region.

The duct may comprise first and second sections, wherein the first section may taper from the inlet to the second section, and the second section may be of constant cross- section from the first section to the outlet, and wherein the distal end of the mandrel is disposed within the second section.

The distal end of the mandrel may be disposed within the heating region. The mandrel may be disposed coaxially with the duct. The heating region may comprise a steam supply to heat the filter material and plasticiser.

The heating region may include a steam chamber formed around a section of the duct, and the duct may include steam vents to allow steam supplied to the steam chamber to pass into the duct to directly heat the filter material.

The apparatus may further comprise a cutting station configured to cut the continuous extruded filter rod into discrete filter rods.

In this specification there are also described a method of manufacturing a filter rod for use in production of a tobacco industry product, the method comprising feeding a first filter material including a plasticiser into an inlet of a duct, the duct tapering along at least a part of its length between the inlet and an outlet, conveying the first filter material through the duct and around a mandrel disposed at least partially within the duct and fixed relative to the duct, such that the first filter material is compressed into a tubular portion, conveying a second filter material through an internal passage extending through the mandrel, expelling the second filter material from an outlet of the internal passage at a distal end of the mandrel to fill the bore of the tubular portion with the second filter material, heating the first filter material within the duct to at least partially cure the plasticiser to harden the first filter material, to produce a continuous filter rod comprising a tubular rod of hardened first filter material with a continuous core of second filter material, and forming grooves into an outer surface of the tubular rod by a plurality of inwardly projecting elements provided with the duct.

The method may comprise expelling the second filter material from the internal passage outlet at the distal end of the mandrel in an axial direction of the mandrel.

The method may comprise expelling the second filter material from the internal passage outlet of the mandrel downstream of the outlet of the duct.

The method may comprise expelling the second filter material from the internal passage outlet of the mandrel within the duct, upstream of the duct outlet. The method may comprise heating the first filter material and plasticiser in a heating region of the apparatus using steam.

The method may comprise heating the first filter material in the heating region to at least partially cure the plasticiser before filling the bore of the tubular rod with the second filter material.

The method may comprise compressing the first filter material to at least partially form the tubular rod before filling the bore of the tubular rod with the second filter material.

The method may comprise providing cellulose acetate tow as the second filter material.

The method may comprise providing the first filter material as cellulose acetate with entrained plasticiser, and providing the second filter material as cellulose acetate with entrained plasticiser, wherein the proportion by weight of plasticiser in the first filter material is greater than the proportion by weight of plasticiser in the second filter material.

The method may comprise providing the second filter material including an aerosol modifying additive.

The method may comprise providing a pre-formed filter rod through the mandrel as the second filter material. The method may comprise comprising cutting the filter rod into smaller discrete filter rods.

Brief Description of the Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 schematically shows a cross-section of a first embodiment of an apparatus for manufacturing filter rods;

Fig. 2 shows an enlarged view of a first portion of the apparatus shown circled in a dashed line in Fig. 1; Fig. 3 shows an enlarged view of a second portion of the apparatus shown circled in a dashed line in Fig. l;

Fig. 4 shows a cross-section through the apparatus of Figs, l and 2 along the line X-X; Fig. 5 shows a cross-sectional view along the line Y-Y as shown in Fig. l, of a first embodiment of a filter rod manufactured using the apparatus of Fig. l;

Fig. 6 shows a first embodiment of a smoking article including a filter made from a filter rod shown in Fig. 5;

Fig. 7 shows a cross-sectional view of a second embodiment of a smoking article including a filter made from a filter rod shown in Fig. 5;

Fig. 8 shows an enlarged schematic view of a portion of a second embodiment of an apparatus for manufacturing filter rods; and

Fig. 9 shows a cross-section through the apparatus of Fig. 8 along the line Z-Z.

Detailed Description

Referring now to Fig. 1, an apparatus 10 of a first embodiment is shown for the manufacture of filter rods and comprises a duct 11 having an inlet 12 and an outlet 13. The duct 11 comprises a first section 11a that narrows from the inlet 12 to an intermediate point 15, and a second section 11b of constant cross-section extending from the intermediate point 15 to the outlet 13. A source of compressed air (shown by arrows 'C') is provided to the duct 11 via compressed air ports 14 which, in use, helps propel filter tow material 16 through the duct 11.

A hollow mandrel 17 is disposed within the duct 11 and comprises an elongate cylindrical member with a hollow passage 18 extending in an axial direction through the centre of the mandrel 17. The passage 18 includes an inlet 18a at a proximal end of the mandrel and an outlet 18b at the opposite, distal end of the mandrel 17. In the exemplary embodiment shown, the mandrel 17 extends through both the first section 11a and second section lib of the duct 11. Also in the exemplary embodiment shown, the distal end of the mandrel 17 is disposed beyond the outlet 13 of the duct 11.

However, the invention is not intended to be limited to this particular feature, as is explained in more detail hereafter. The mandrel 17 is fixedly secured in the apparatus 10 so as to be fixed relative to the duct 11. The outlet 18b of the mandrel 17 is advantageously open in an axial direction of the mandrel 17. That is, the outlet opening 18b faces in a downstream axial direction of the passage 18 and of the duct 11. (Herein, "upstream" and "downstream" are used in reference to the direction of conveyance of the first and second filter materials 16, 27 through the apparatus). The second section lib of the duct 11 has a central bore or passage 19 which is configured with a plurality of projecting elements 19a which project inwardly from an inner wall of the passage 19. This is shown more clearly in the cross-sectional view along the line X-X shown in Fig. 4. The cross-sectional shape of the duct 11 with the projecting elements 19a may be uniform along the length of the second section 11b. The mandrel 17 is spaced from the inner wall of the passage 19 of the second duct section 11b. A heating region 20 is provided in combination with and around a portion of the second duct section 11b. The heating region 20 comprises a closed chamber 21 around the second duct section 11b with steam inlets 22. The second duct section 11b includes a plurality of steam vents 23 which, in use, allow steam provided to the chamber 21 to pass into the bore 19 of the second duct section 11b. A source of dry steam (not shown) is connected to the steam inlets 22 to supply hot dry steam to the chamber 21.

A cutting station 24 is provided downstream of the outlet 13 of the duct 11 and includes a cutting blade 25. In use, a first filter material 16, such as filter tow material, for example cellulose acetate tow mixed with a plasticiser, is fed into the inlet 12 of the duct 11. The first filter material 16 is mixed with the plasticiser, such as triacetate, advantageously in a ratio of around 10 - 15% by weight, although other ratios of plasticiser may be used within the scope of the invention, such as between 4% and 20% by weight. Herein, the term "filter material" is intended to encompass material that performs, may perform, or is capable of performing a function of filtering fluid flow which may pass through the material.

The first filter material 16 with entrained plasticiser is conveyed through the first duct section 11a using jets of compressed air provided through the compressed air ports 14. As the first filter material 16 is conveyed through the duct 11, it passes around the mandrel 17 and is compressed into a continuous cylindrical filter rod 26 as it passes through the tapering first duct section 11a. The first filter material 16 is formed around the mandrel 17 and is thereby compressed into a tubular filter rod 26 with a hollow bore. Simultaneously, the projecting elements 19a form continuous grooves 26a in the outer surface of the continuous filter rod 26 extending in an axial direction of the continuous filter rod 26. This is shown more clearly in the cross-sectional view of Fig. 4. It will be appreciated that Fig. 4 shows a schematic view of the cross-section of the second duct section lib and continuous filter rod 26 formed therein, and is not intended to be to scale or accurately represent the shape of the continuous filter rod 26 within the second duct section lib, or the extent to which the continuous filter rod 26 occupies space within the bore 19 of the second duct section 11b.

At the same time as the first filter material 16 is conveyed through the duct 11, a second filter material 27 is fed into the open end 18a of the passage 18 of the mandrel 17 and is conveyed through the passage 18.

As the tubular filter rod 26 passes through the second duct section 11b around the mandrel 17, it passes into the heating region 20. Dry steam at around 170 degrees Celsius is supplied to the chamber 21 and passes through the steam vents 23 and into the first filter material 16 of the filter rod 26. The steam permeates and heats the first filter material 16. The first filter material 16 is also heated by being in contact with the second duct section 11b which itself is heated by the steam. The supplied heat cures or substantially cures the entrained plasticiser in the first filter material 16 so that the continuous filter rod 26 hardens to form a stiff continuous grooved filter rod. The hardened continuous filter rod therefore has the grooves 26a set therein. The continuous hardened filter rod 26 exits the heating region 20 and exits the duct 11 through the outlet 13. The high-temperature steam also plays a role in providing hardened surface of the filter rod 26, by causing the fibres of the tow material to fuse. This fusing of the fibres occurs within the second duct section 11b. The second filter material 27 is conveyed through the passage 18 in the mandrel 17 and is expelled out of the outlet 18b into the hollow core of the filter rod 26. The second filter material 27 is advantageously expelled out of the outlet 18b in an axial direction of the mandrel 17. Thereby, the second filter material 27 fills the hollow core of the filter rod 26 to form a continuous coaxial grooved filter rod 28 comprising a hardened outer tubular portion of the first filter material 16, in which the continuous grooves are formed on its outer surface, and an inner core of the second filter material 27.

After the hardened continuous filter rod 28 exits the outlet 13 of the duct 11, it passes to the cutting station 24 where the cutting blade 25 cuts the hardened continuous filter rod 28 into individual lengths of discrete filter rods 29. These may be single length filter rods 29 of a size suitable for use in combination with a single tobacco rod to make a single smoking article. Alternatively, the discrete filled-core filter rods 29 may be "2- up", "4-up" rods, or other lengths which are a multiple of a single length filter that would be joined to a tobacco rod in a finished smoking article. Such multiple length filters can be supplied to subsequent smoking article or other tobacco industry product manufacturing machinery to be cut to length in later processing steps.

A discrete filter rod 29 of the invention manufactured using the above-described apparatus and method is shown in cross-section in Fig. 5. The filter rod 29 is substantially cylindrical and is continuous in cross-section along its length. The filter rod 29 comprises an outer tubular section 30 of hardened first filter tow material 16, and core 31 of the second filter material 27. Continuous grooves 32 are formed around the outer surface of the filter rod 29 extending in an axial direction thereof.

The filter rods 29 manufactured using the above-described apparatus and method are sufficiently stiff and strong not to require any outer plug wrap layer to be applied to maintain their shape and structural integrity. As such, the grooved filter rods 29 can be provided directly to a subsequent smoking article manufacturing process and the absence of requiring an outer plug wrap means the manufacturing process is simpler, quicker, more efficient and more cost effective than known filter manufacturing processes where a subsequent filter rod wrapping step is performed, which requires additional machinery and materials. The filter rods 29 are also able to be

manufactured to be accurately symmetrical about their central axis, that is, accurately circular in cross-section. This is at least in part because any oval distortion which may be caused by overlapping plug wrap seams of known wrapped filters is avoided.

Fig. 6 shows one exemplary configuration of a smoking article 40 incorporating a discrete filter rod 29 as described above. (Although, as described above, in a smoking article the filter segment may be a section cut from a multiple length filter rod 29, the filter rod segment within the smoking article 40 will be referred to herein as "filter rod 29"). The smoking article 40 comprises a tobacco rod 41 with a filter rod 29 abutting one end of the tobacco rod 41 and joined thereto by a tipping wrapper 42 which overlies the join between the tobacco rod 41 and the filter rod 29. In the exemplary smoking article 40, ventilation holes 43 are provided to allow ambient air to be drawn into the filter rod 29 for increased ventilation as a user draws on the smoking article 40 in use. Also in the exemplary smoking article 40, the core 31 is visible at the end of the smoking article 40. This can provide a visual indicator to a consumer of the type of smoking article 40 and its associated filter performance and/or flavour. Also, the ends of the grooves 32 are visible which can provide an indication to the user of the technical ventilation function, and also an improved mouth end appearance.

A second embodiment of an apparatus 10 for manufacturing a grooved filter rod 29 is shown in Figs. 8 and 9, in which features in common with the first embodiment described above retain the same reference numerals. A difference with the second embodiment is that the passage 19 within the second duct section 11b does not include projecting elements on an inner wall thereof. In this alternative, second embodiment, the outlet 13 of the second duct section 11b includes a threaded section 61 on the inside surface of the bore passage 19, and a die 62 with a threaded outer surface is secured in the outlet 13 in the threaded section 61. The die 62 includes an outlet aperture 63 through which the first filter material 16 is extruded to form the outer tubular section 30. The die 62 includes a plurality of inwardly projecting elements 64 which form the grooves 26a in the continuous filter rod 28. The die 62 may be removable from the second duct section 11b, to allow for maintenance or replacement, and also to allow the die 62 to be interchanged with other dies which may have a difference shaped or sized outlet aperture 63 or size, shape or arrangement of projecting elements 64, to enable production of difference configurations of filter rod 29. For example, the spacing, projecting distance and shape of the projecting elements 64 may vary. However, it is intended within the scope of the invention that the die 62 may alternatively be an integral part of the second duct section 11b. It will also be appreciated that, if the die 62 is removable from the duct 11, then other means of securing the die 62 to the duct 11 may be used, for example a bayonet socket fitting.

In the above-described apparatus of the second embodiment of the invention, it is intended within the scope of the invention that the distal end of the mandrel 17 (i.e. in which the outlet 18b of the passage 18 is provided) may be disposed upstream of the die 62, as shown in solid lines in Fig. 8. This may result in less resistance to the passage of the first and second filter materials 16, 27 through the die 62. In addition, the distal end of the mandrel 17 may be disposed within the aperture 63 of the die 62, or downstream of the die 62, as shown in broken lines in Fig. 8. This may help provide increased force with which the grooves 26a are formed on the outside surface of the continuous filter rod 28. The grooved filter rods 29 of embodiments of the invention manufactured using the above-described apparatuses and methods have a hardened grooved outermost surface formed of hardened filter tow material. This may be advantageous in tobacco industry products in which a rotatable filter section is provided and in which some form of ratchet function may be desired in the rotatable filter section. In such a tobacco industry product, a projection or pawl may engage with the grooves 32 and the hardened first filter material 16 may provide a more positive detent position of the pawl within the grooves 22, and also a more audible click or other sound as the pawl locates in a groove 32. This may also provide a more detectable tactile and sensory feedback to the user as the pawl locates in a detent position, and also make definition of rotational positions more secure. The smoking article of Fig. 6 may comprise such a rotatable mouthpiece section which may be provided with a ratchet or pawl as mentioned above, to create a tactile and audible click as the mouthpiece portion is rotated to detent positions.

In one embodiment, the second filter material 27 fed into the inlet 18a of the passage 18 of the mandrel 17 may be a loose filter tow material, such as cellulose acetate. The loose tow material may be conveyed under pressure or force through the passage 18, and/ or may be pulled through the mandrel 17 by conveyance of the downstream outer first filter material 16 with which it is encircled. The second filter tow material 27 may also comprise entrained plasticiser, which may advantageously be of a lower proportion by weight than that of the first filter material. For example, the second filter material may comprise between 7 - 12% plasticiser by weight, advantageously between 7 - 10% by weight, and more advantageously between 8 - 9% by weight. Thereby, the core 31 of the filter rods 29 may be softer and more permeable to smoke drawn through the filter rod 29 than the outer tubular section 30.

The passage 18 maybe configured to taper inwardly along at least a part of its length, between in inlet 18a and the outlet 18b, such that the tow material of the second filter material 27 is compressed as it is conveyed through the passage 18. The core 31 of the resulting filter rod 29 thereby may comprise a compressed filter tow material.

The mandrel 17 extending entirely through the duct 11 may advantageously enable curing or part-curing of the first filter material 16 within the duct 11. Also, the tubular filter rod 26 may be at least partially hardened before the second filter material 27 is introduced into its hollow bore. However, the invention is not intended to be limited to the embodiment shown in which the mandrel 17 extends entirely through the duct 11. In an alternative embodiment, the distal end of the mandrel 17 may be disposed within the duct 11 upstream of the outlet 13. In such an embodiment, the second filter material 27 would be expelled into the hollow bore of the tubular filter rod 26 within the duct 11. The distal end of the mandrel 17 may be disposed within the heating region 20, or may be disposed downstream of the heating region 20 but upstream of the outlet 13 of the duct 11.

The second filter material 27 being fed under pressure and/or being a compressed material, may advantageously facilitate formation of the continuous filter rod 26 into a desired shape. This may result from the second filter material 27 exerting an outward force on the surrounding first filter tow material 16 that forms the outer tubular section 30. In particular, in an alternative embodiment described above in which the distal end of the mandrel 17 is disposed within the duct 11, this force may help press the first filter material 16 against the inner wall of the bore 19 of the second duct section 11b and so encourages the first filter material 16 to harden in close conformity with the inner wall of the duct 11. This may also help ensure the grooves 26a are formed cleanly and accurately on the outer surface of the continuous filter rod 26, helping improve the uniformity and product quality of the resulting hardened filter rods 29.

In an alternative embodiment of the invention, the second filter material 27 may comprise a smoke modifying material and may comprise, for example, a granular material such as flavourant or activated charcoal. These could be provided exclusively as the second filter material 27 or may be entrained in a carrier material, for example, entrained in cellulose acetate tow. Furthermore, the second filter material 27 may include an entrained flavourant. The flavourant may be provided as a solid particulate material such as flavourant granules, or may be provided as a liquid absorbed into a carrier material such as cellulose acetate tow. In any of the above-described embodiments of the invention, if the second filter material 27 comprises a filter material such as cellulose acetate tow, the tow of the second filter material 27 may be the same composition than the tow of the first filter material 16 that forms the outer tubular section 30 or may be of a different

composition. If the second filter material 27 is a cellulose acetate tow of a different composition, this may provide the core 31 with a different filtering characteristic to the outer tubular section 30. For example, the core 31 may have a greater or lesser draw resistance than the outer tubular section 30. The relative draw resistance of the core 31 and outer tubular section 30 may be chosen to control the amount of smoke that, in use, is drawn through each part of the filter rod 29. For example, if the core 31 has a lower draw resistance than the outer tubular section 30, a larger proportion of the smoke stream may flow through the core 31 than through the outer tubular section 30. This proportion can thereby be controlled to determine, for example, the amount of flavourant that may be entrained in the smoke stream, or the proportion of the smoke stream that passes over activated charcoal granules. An increased level of plasticiser and hardening of the outer tubular section 30 can give an increased draw resistance to the outer tubular section than that of the inner core 31.

The outer tubular section 30 being hardened provides smoking articles 40, 50 with structural strength during smoking by a consumer. This can help avoid deformation of the filter during smoking, and also provide tactile resistance to any "chewing" action of the consumer on the filter during smoking.

In an alternative embodiment of the invention, the second filter material 27 may comprise tobacco or reconstituted tobacco. The tobacco material may thereby impart a tobacco flavour to the proportion of the smoke stream that passes through the core 31 of the filter rod 29.

In a further embodiment of the invention, the second filter material 27 may be coloured and thereby may contrast with the first filter material 16 of the outer tubular section 30. This may provide a user with a visual indicator of the filter and/or flavour properties of the filter rod 29. For example, a second filter material 27 with a menthol flavour may be coloured green. Furthermore, a range of smoking articles may be provided that offer a range of smoking properties, for example differing filtering properties of flavour types or strengths. The core 31 of the filter rods 29 of such various different smoking articles may be coloured in different shades of a particular colour, or different colours, to indicate said different properties. Coloured second filter material 27 of the core 31 may also reduce colouring of the second filter material 27 during smoking of the smoking articles 40, 50, by disguising or at least partially concealing discolouration caused by smoke constituents entrained in the smoke drawn through and retained by the filter. This may be advantageous in an embodiment in which the draw resistance of the core 31 is lower than the draw resistance of the outer tubular section 30, such that a major proportion of the smoke drawn through the filter is drawn through the core 31. In the smoking article 40 described above, a single discrete filter rod 29 is provided abutting the tobacco rod 41 and so the core 31 of the filter rod 29 is visible at the mouth-end of the smoking article 40. The may provide the advantages described above. However, alternative embodiments of smoking articles are envisaged incorporating the above-described core-filled filters. Such smoking articles may include multi-segment filters. A second embodiment of smoking article 50 is shown in cross-section in Fig. 7. Like features with the first embodiment of smoking article 40 retain the same reference numerals. The smoking article 50 of the second embodiment comprises a multi-segment filter 51 which comprises a first filter segment 29 as per the filter rod 29 described above, and a second filter segment 52 adjacent the first filter segment. The second filter segment 52 comprises a plug of a material such as cellulose acetate, which may be without an entrained particulate additive or core of different material.

A plug wrap 53 extends around the first and second filter segments 29, 52. The filter 51 is joined to a tobacco rod 41 by a tipping wrapper 42. The filter 51 is arranged such that the second filter segment 52 is disposed at the mouth-end of the smoking article, and the first filter segment 29 is disposed between the second filter segment 52 and the tobacco rod 41. The smoking article 50 of the second embodiment may be

advantageous in the case where the core 31 of the first filter segment 29 comprises a particulate material, either entrained in a carrier material as described above, or exclusively as the core material. For example, if the core 31 comprises tobacco or charcoal granules entrained in cellulose acetate tow. In such case, the second filter segment 52 prevents the particulate material from coming out of the core 31 of the first filter segment 29 and into a user's mouth when a user draws on the smoking article 50 in use. It may also provide the mouth-end of the smoking article 50 with a

conventional appearance, namely a filter end with a plain end face of continuous filter material. This may be beneficial to enable provision of improved filtering and/or flavour delivery functions using a core-filled filter as described above, without presenting the consumer with a visually different smoking article to that of their regular preferred smoking articles.

The apparatuses 10 and the methods for filter manufacture avoids use of a conventional garniture belt and plug wrap, thereby avoiding the added complexity and materials of conventional filter rod manufacture and therefore the associated costs. Also, a continuous core of filter material is provided in the filter rods 29 in a process that enables high-speed production. Such apparatuses 10 also avoid the need for complex moving mechanisms such as those that may be required in the manufacture of other types of filter which have spaced elements within the filter core. Such mechanisms which may intermittently insert capsules or other elements at regular spacing within a filter core are complex and may require complex control systems to remain accurately in register to ensure the filters produced are consistent and have core elements inserted at the correct spacing. Such mechanisms are therefore costly to produce and maintain.

In the apparatuses 10 described above, the heating region 20 is formed around a section of the duct 11. This may advantageously allow for a compact apparatus configuration. However, the invention is not intended to be limited to such a configuration and in an alternative embodiment, the heating region 20 may be provided at a separate duct section into which the compressed and extruded continuous filter rod 26 is fed. This latter alternative configuration may advantageously facilitate maintenance of the apparatus, as the heating region may be separable from the duct section in which the filter material is compressed into a continuous filter rod, enabling easier access and cleaning.

The mandrel 17 may include means to facilitate the second filter material 27 being conveyed though the passage 18 from the inlet 18a to the outlet 18b. Such means may comprise a compressed air supply coupled to the mandrel 17 to pass compressed air through the passage together with the second filter material 27 in a similar manner to how the loose filter tow material 16 is conveyed through the duct 11. The mandrel 17 may include one or more compressed air ports (not shown) extending through a side wall thereof for the supply of compressed air into the passage 18. However, the invention is not limited to such a configuration and the second filter material 27 may be drawn through the mandrel 17 by being entrained in the first filter material 16 conveyed through the duct 11.

The passage 18 of the mandrel 17 is shown as tapering to narrow between the inlet 18a and the outlet 18b. However, the invention is not intended to be limited to such a configuration and the passage 18 within the mandrel 17, may be of a constant cross- section along its length. Furthermore, the outer surface of the mandrel 17 is shown as narrowing from the inlet 18a end. However, the invention is not limited to such a configuration and the mandrel 17 may be of a constant cross-section along its length. An advantageous configuration of the apparatuses 10 of the invention comprises the duct 11 tapering to narrow along at least part of the length of the mandrel 17. That is, the distance between the outer surface of the mandrel 17 and the inner surface of the duct 11 reduces along at least a part of the length of the duct 11 in a conveyance direction of the first filter material 16. This helps compress and at least partially form the first filter material 16 into the hollow tubular section 30 before introduction of the second filter material 27 from within the passage 18 of the mandrel 17.

The apparatuses 10 and methods of the invention described above comprise second filter material 27 being introduced into a hollow core of the outer tubular section 30. Although the second filter material 27 may be loose, such as a fibrous tow or a granular material, the invention is not intended to be limited to such second filter material 27. It is intended in an embodiment of the invention that the second filter material 27 may comprise a pre-formed slim continuous filter rod to form the core 31 of the discrete filter rod 29. The first filter material 16 would then be formed around the pre-formed slim filter rod. Such pre-formed filter rods used as the second filter material 27 may be of a size as in known super-slim smoking articles. In such an embodiment, the preformed slim filter rod could be conveyed through the apparatus 10 by being pulled though by the conveyance of the surrounding first filter material 16. In all

embodiments, the continuous filter rods 28 may be pulled through the duct 11 by down- stream conveyance drivers (not shown) such as one or more driven rollers, wheels or belts.

An advantageous configuration of the apparatus 10 and method of the invention, and filter rod 29 formed thereby, is that the core 31 and outer tubular section 30 are each formed of a generally homogenous material although each are separate materials. That is, the material of the core 31 is not mixed or blended with the material of the outer tubular section 30 and a clear boundary exists between each part of the filter rod 29. As well as providing a distinctive and clean appearance, this also allows accurate control of the filtering characteristics and performance of the filter rod 29 of the invention. This may advantageously be facilitated by curing or at least part curing of the first filter material 16 before introduction of the second filter material into the core of the tubular filter rod 26. This may be achieved by the distal end of the mandrel 17 being disposed within or downstream of the heating region 20.

In embodiments of the apparatuses 10 of the invention, the mandrel 17 extends into the heating region 20 such that the distal end of the mandrel 17 may be disposed within or downstream of the heating region 20. This may advantageously enable at least partial curing of the first filter tow material 16 forming the outer tubular section 30 before introduction of the second filter material 27. This may advantageously help avoid collapse of the outer tubular section 30 during formation. The mandrel 17 extending entirely through the heating region 20 may advantageously enable improved hardening of the outer tubular section 30 around the mandrel 17 before introduction of the second filter material 27 and so provide improved circularity and/or uniformity of the formed filter rods 29. The invention is not limited to specific temperature of steam being supplied to the heating region 20 and the temperature of the dry steam may vary within the scope of the invention. For example, between 100 - 200 degrees Celsius, and may be between 120 - 190 degrees Celsius, and may be between 150 - 180 degrees Celsius.

Furthermore, the temperature of the steam may be selected proportional to the amount of plasticiser entrained in the first filter material 16 and/ or also the conveyance speed of the first filter material 16 through the duct 11.

In an advantageous configuration of the apparatuses 10 of the invention, the duct 11 and mandrel 17 are elongate and comprise respective central axes, and the duct 11 and mandrel 17 are co-axial. This may advantageously enable formation of symmetrical and uniform filter rods 29.

As used herein, the term "tobacco industry product" is intended to include smoking articles comprising combustible smoking articles such as cigarettes, cigarillos, cigars, tobacco for pipes or for roll-your-own cigarettes, (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, tobacco substitutes or other smokable material), electronic smoking articles such as e-cigarettes, heating devices that release compounds from substrate materials without burning such as tobacco heating products, hybrid systems to generate aerosol from a combination of substrate materials, for example hybrid systems containing a liquid or gel or solid substrate; and aerosol-free nicotine delivery articles such as lozenges, gums, patches, articles comprising breathable powders and smokeless tobacco products such as snus and snuff.

In some embodiments, the tobacco industry product is a non-combustible smoking article. In some embodiment the tobacco industry product is a heating device which releases compounds by heating, but not burning, a substrate material. The material maybe for example tobacco or other non-tobacco products, which may or may not contain nicotine. In some embodiments the heating device is a tobacco heating device. In other embodiments the tobacco industry product is a hybrid system to generate aerosol by heating, but not burning, a combination of substrate materials. The substrate materials may comprise for example solid, liquid or gel which may or may not contain nicotine. In some embodiments, the hybrid system comprises a liquid or gel substrate and a solid substrate. The solid substrate may be for example tobacco or other non-tobacco products, which may or may not contain nicotine. In some embodiments the hybrid system comprises a liquid or gel substrate and tobacco.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced and provide for superior filters, and apparatuses and methods for manufacture of filters. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope and/ or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future.

Claims

A filter rod for use in a tobacco industry product comprising an extruded tubular portion formed from a first filter material and having an outer surface comprising a plurality of continuous grooves extending in an axial direction of the tubular portion and defining a grooved outermost surface of the filter rod, and

a continuous extruded core of second filter material provided within the tubular portion.

A filter rod according to claim 1 wherein the first filter material comprises cellulose acetate tow which is hardened with a plasticiser.

A filter rod according to claim 1 of claim 2 wherein the filter rod does not comprise any outer wrap around the tubular portion.

A filter rod according to any of claims 1 to 3 wherein the second filter material of the core comprises cellulose acetate.

A filter rod according to claim 4 wherein the second filter material comprises an aerosol modifying additive.

A filter rod according to any of claims 1 to 5 wherein the first filter material comprises cellulose acetate with entrained plasticiser, and the second filter material comprises cellulose acetate with entrained plasticiser, and wherein the proportion by weight of plasticiser in the first filter material is greater than the proportion by weight of plasticiser in the second filter material.

A filter rod according to any of claims 1 to 6 wherein the grooves are of uniform size and regularly spaced around the circumference of the filter rod.

A filter rod according to any of claims 1 to 7 wherein the grooves extend continuously and without interruption around the entire circumference of the filter rod.

A filter for a tobacco industry product comprising a first filter segment formed from a filter rod according to any of claims l to 8, and a second filter segment axially aligned with the first filter segment and joined thereto by a plug wrap around the filter rod and second filter segment.

A tobacco industry product comprising a tobacco rod and a filter formed from a filter rod according to any of claims l to 8 or a filter according to claim 9.

A tobacco industry product according to claim 10 wherein the filter includes a rotatable section, and a pawl engageable in the grooves of the filter to define discrete rotational positions of the rotatable section.

An apparatus for manufacturing a filter rod for use in production of a tobacco industry product, the apparatus comprising:

a duct having an inlet configured to receive a first filter material, and an outlet, the duct tapering along at least a part of its length between the inlet and the outlet;

a mandrel disposed at least partially within the duct and fixed relative to the duct;

wherein the mandrel includes an internal passage extending

therethough through which a second filter material may be conveyed;

the passage including an outlet at a distal end of the mandrel though which the second filter material may be expelled; and

a heating region configured to heat the first filter material within the duct;

the apparatus configured such that the first filter material conveyed through the duct is compressed around the mandrel into a tubular portion, the second filter material fed though the internal passage of the mandrel is expelled out of the passage outlet to fill the bore of the tubular portion, and plasticiser entrained in the first filter material is at least partially cured to harden the first filter material, to produce a continuous filter rod comprising a tubular rod of hardened first filter material with a continuous core of second filter material; and wherein

the duct is provided with a plurality of inwardly projecting elements to contact the tubular rod to form grooves into an outer surface of the tubular rod.

13· An apparatus according to claim 12 wherein the inwardly projecting

elements are provided on an inside wall of the duct.

14. An apparatus according to claim 13 wherein the duct comprises first and second sections, wherein the first section tapers from the inlet to the second section, and the second section is of constant cross-section from the first section to the outlet, and wherein the inwardly projecting elements extend continuously in an axial direction along at least a portion of the second section.

15. An apparatus according to claim 12 wherein the duct comprises a die and the inwardly projecting elements are formed on the die.

16. An apparatus according to claim 15 wherein the die is detachable from the duct.

17. An apparatus according to any of claims 12 to 16 wherein the inwardly

projecting elements are of a uniform size and are regularly spaced around the duct.

18. An apparatus according to any of claims 12 to 17 wherein the internal

passage of the hollow mandrel includes a tapered section which narrows in a direction towards the distal end of the mandrel.

19. An apparatus according to any of claims 12 to 18 wherein a distance between an outer surface of the mandrel and an inner surface of the duct reduces along at least a part of the length of the duct in a direction towards the distal end of the mandrel.

20. An apparatus according to any of claims 12 to 19 wherein the distal end of the mandrel is positioned downstream of the outlet of the duct.

21. An apparatus according to any of claims 12 to 20 wherein the mandrel extends entirely through the length of the duct.

22. An apparatus according to any of claims 12 to 19 wherein the distal end of the mandrel is positioned within the duct.

23. An apparatus according to any of claims 12 to 22 wherein the mandrel extends into the heating region.

24. An apparatus according to any of claims 12 to 23, wherein the duct

comprises first and second sections, wherein the first section tapers from the inlet to the second section, and the second section is of constant cross- section from the first section to the outlet, and wherein the distal end of the mandrel is disposed within the second section.

25. An apparatus according to claim 23 or claim 24, wherein the distal end of the mandrel is disposed within the heating region.

26. An apparatus according to any of claims 12 to 25 wherein the mandrel is disposed coaxially with the duct.

27. An apparatus according to any of claims 12 to 26 wherein the heating region comprises a steam supply to heat the filter material and plasticiser.

28. An apparatus according to claim 27 wherein the heating region includes a steam chamber formed around a section of the duct, and the duct includes steam vents to allow steam supplied to the steam chamber to pass into the duct to directly heat the filter material.

29. An apparatus according to any of claims 12 to 28 further comprising a

cutting station configured to cut the continuous extruded filter rod into discrete filter rods.

30. A method of manufacturing a filter rod for use in production of a tobacco industry product, the method comprising feeding a first filter material including a plasticiser into an inlet of a duct, the duct tapering along at least a part of its length between the inlet and an outlet, conveying the first filter material through the duct and around a mandrel disposed at least partially within the duct and fixed relative to the duct, such that the first filter material is compressed into a tubular portion, conveying a second filter material through an internal passage extending through the mandrel, expelling the second filter material from an outlet of the internal passage at a distal end of the mandrel to fill the bore of the tubular portion with the second filter material, heating the first filter material within the duct to at least partially cure the plasticiser to harden the first filter material, to produce a continuous filter rod comprising a tubular rod of hardened first filter material with a continuous core of second filter material, and forming grooves into an outer surface of the tubular rod by a plurality of inwardly projecting elements provided with the duct.

A method according to claim 30 comprising expelling the second filter material from the internal passage outlet at the distal end of the mandrel in an axial direction of the mandrel.

A method according to claim 30 or claim 31 comprising expelling the second filter material from the internal passage outlet of the mandrel downstream of the outlet of the duct.

A method according to claim 30 or claim 31 comprising expelling the second filter material from the internal passage outlet of the mandrel within the duct, upstream of the duct outlet.

A method according to any of claims 30 to 33 comprising heating the first filter material and plasticiser in a heating region of the apparatus using steam.

A method according to claim 34 comprising heating the first filter material in the heating region to at least partially cure the plasticiser before filling the bore of the tubular rod with the second filter material.

A method according to any of claims 30 to 35 comprising compressing the first filter material to at least partially form the tubular rod before filling the bore of the tubular rod with the second filter material.

A method according to any of claims 30 to 36 comprising providing cellulose acetate tow as the second filter material.

A method according to claim 37 comprising providing the first filter material as cellulose acetate with entrained plasticiser, and providing the second filter material as cellulose acetate with entrained plasticiser, wherein the proportion by weight of plasticiser in the first filter material is greater than the proportion by weight of plasticiser in the second filter material.

A method according to claim 37 or claim 38 comprising providing the second filter material including an aerosol modifying additive.

A method according to any of claims 30 to 39 comprising providing a preformed filter rod through the mandrel as the second filter material.

A method according to any of claims 30 to 40 further comprising cutting the filter rod into smaller discrete filter rods.

A filter rod for use in a tobacco industry product substantially as

hereinbefore described with reference to the accompanying drawings.

An apparatus for manufacturing a filter rod for use in production of a tobacco industry product substantially as hereinbefore described with reference to the accompanying drawings.

A method of manufacturing a filter rod for use in production of a tobacco industry product substantially as hereinbefore described with reference to the accompanying drawings.