WO2011117584A1

WO2011117584A1 - Tobacco smoke filter

Info

Publication number: WO2011117584A1
Application number: PCT/GB2011/000421
Authority: WO
Inventors: Paul Francis Clarke; Jonathan P. Aimson
Original assignee: Filtrona International Limited
Priority date: 2010-03-24
Filing date: 2011-03-24
Publication date: 2011-09-29
Also published as: GB201004976D0; EP2549896A1; HUE045493T2; CN102905568A; PL2549896T3; JP2016105718A; RU2012142714A; KR20130007612A; JP2013521820A; LT2549896T; EP2549896B1; UA110107C2; CN105476064A

Abstract

A tobacco smoke filter or filter element comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material, wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged, to define a cavity at the second end of the filter; the filter or filter element further comprising an additive distanced from the second end of the outer wrapper and/or core.

Description

TOBACCO SMOKE FILTER

The present invention relates to filters and filter elements for smoking articles such as cigarettes.

Recess filters are well known in the tobacco industry and provide a unique end appearance for cigarettes. They are typically manufactured by wrapping a continuous stream of filter segments at spaced intervals in a relatively stiff plug wrap paper. By cutting the filter stream in a region where no filter segment (element) is present, a recess filter can be obtained - the stiff plugwrap paper providing sufficient rigidity to enable the final cigarette to be manufactured and used without crushing the exposed paper end of the filter.

Recess filters can incorporate one, two or more filter segments. If it is desired to incorporate activated carbon or other particulate additive within the filter, it has been necessary to use at least two segments - the segment closest to the mouth end generally comprising cellulose acetate so as to present a plain white end (within the recess, or cavity) to the smoker and the segment closest to the tobacco column typically comprising carbon (or other) granules interspersed within a fibrous matrix. The requirement to use at least two segments in order to incorporate particulate additive into a recess filter increases the complexity and cost of manufacture of carbon recess filters. Further, there are implications for e.g. a conventional two segment superslim (e.g. of circumference 16mm) activated carbon containing recess filter, because there is a limit to the weight of carbon that can be incorporated within the carbon-bearing segment of such a two segment filter, beyond which the increase in filter pressure drop leads to unsatisfactory smoking characteristics. There is a need for a recess filter which overcomes these problems.

According to the present invention there is provided a tobacco smoke filter (or filter element) comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material, wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged, to define a (e.g. tubular) cavity at the second end of the filter; the filter (or filter element) further comprising an additive (e.g. a particulate additive) distanced from the second end of the outer wrapper and/or core. The radially inner face of the outer wrapper which extends beyond the second end of the core around which is engaged may define (e.g. with the second end of the longitudinally extending core) a cavity or recess, e.g. a tubular cavity/recess, at the second end of the recess filter.

The particulate additive is distanced from the second end of the wrapper and/or core such that it is not visible from the second end of the wrapper and/or core.

In an example, the single longitudinally extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material having fully enclosed (e.g. embedded) therewithin a (or at least one) pocket of additive (e.g. particulate additive). The rod shaped core of tobacco smoke filtering material may optionally have an additional wrapper (e.g. porous or non porous) engaged around the rod shaped core. The provision of the fully enclosed pocket of additive within the core of the tobacco smoke filtering material has the effect that the additive is distanced from the second end of the core (because there is tobacco smoke filtering material between the pocket of additive and the end of the core).

The single longitudinally extending core of tobacco smoke filtering material may have fully enclosed (e.g. embedded) therewithin a single pocket of additive (e.g. particulate additive) close to the first end (e.g. the tobacco end in a filter cigarette) and remote from the second end (e.g. the buccal or mouth end). The single longitudinally extending core of tobacco smoke filtering material may have fully enclosed (e.g. embedded) therewithin a single pocket of additive (e.g. particulate additive) positioned equidistantly between the first end of the core (e.g. the tobacco end in a filter cigarette) and the second end of the core (e.g. the end of the core closest to the buccal or mouth end in a filter cigarette). The single longitudinally extending core of tobacco smoke filtering material may have fully enclosed therewithin one or more (e.g. two, three, four) separate pockets of additive (e.g. particulate additive). The fully enclosed (e.g. embedded) pockets of additive may taper towards one or both ends - e.g. may be of a generally ellipsoidal configuration. If there is more than one pocket of additive, these may have even longitudinal spacing. Other pocket dispositions are possible - e.g. relatively close longitudinal spacing alternating with longer spacing - it being possible to achieve this by appropriate adjustment of the manufacturing process. The single longitudinally extending core of tobacco smoke filtering material comprising a rod shaped core of tobacco smoke filtering material having fully enclosed (e.g. embedded) therewithin a (or at least one) pocket of additive (e.g. particulate additive) may be manufactured, for example, by the methods and apparatus disclosed in WO 2006/059134. According to the present invention there is provided a tobacco smoke filter comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material; wherein the single longitudinal extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material having fully enclosed (e.g. embedded) therewithin a (or at least one) pocket of additive (e.g. particulate additive); wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged to define a cavity (recess) at the second end of the filter. The rod shaped core of tobacco smoke filtering material may optionally have an additional wrapper engaged around the rod shaped core. The radially inner face of the outer wrapper which extends beyond the second end of the core around which is engaged may define (e.g. with the second end of the longitudinally extending core) a cavity or recess, e.g. a tubular cavity/recess, at the second end of the filter.

In another example, the single longitudinally extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material and an additive (e.g. particulate additive) bearing wrapper engaged around the rod shaped core, the additive bearing wrapper having additive (e.g. particulate additive) adhered to one or more portion(s) of the radially inner face thereof with said additive bearing wrapper being free of additive around its circumference at the second end of the core. The absence of additive at the second end of the additive bearing wrapper has the effect that the additive is distanced from the second end of the core (because there no additive on the wrapper at the second end of the core). Preferably the additive bearing wrapper is free of additive around its circumference at both first and second ends of the core. The longitudinally extending core of tobacco smoke filtering material comprising a rod shaped core of tobacco smoke filtering material and an additive (e.g. particulate additive) bearing wrapper engaged around the rod shaped core, may be a filter element as disclosed in GB 2261152. The additive bearing wrapper may be porous or non porous.

Thus, according to the present invention there is provided a tobacco smoke filter comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material; wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged to define a (e.g. tubular) cavity at the second end of the filter; the single longitudinally extending core of tobacco smoke filtering material comprising a rod shaped core of tobacco smoke filtering material and an additive (e.g. particulate additive) bearing wrapper engaged around the rod shaped core, the additive bearing wrapper having additive adhered to one or more portion(s) of the radially inner face thereof with said additive bearing wrapper being free of additive around its circumference at the second end of the core. The radially inner face of the outer wrapper which extends beyond the second end of the core around which is engaged may define (e.g. with the second end of the longitudinally extending core) a cavity or recess, e.g. a tubular cavity/recess, at the second end of the filter. In a further example the outer wrapper may have additive (e.g. a particulate additive) adhered to one or more portion(s) of the radially inner face thereof with said outer wrapper being free of the additive around its circumference at the second end of the wrapper. The outer wrapper may be free of additive in a region extending from the second end of the wrapper (towards the first end), the region extending at least up to, and preferably further than, the distance by which the second end of the wrapper extends beyond the second end of the core around which is engaged to define the cavity. The inner face of the wrapper which extends beyond the second end of the core around which it is engaged to define the cavity at the second end of the filter is therefore free of additive around its circumference, so that no additive is visible on the inner face of the walls of the cavity.

The present applicant has found that e.g. 'monocarbon' filters - i.e. filters incorporating a single longitudinally extending core of filtering material and additive (e.g. carbon) that have at least one end free of additive and e.g. which can be manufactured in a one-pass process (including the 'Active Patch' filter, as disclosed in, for example, GB 2261152, and the 'Smooth Core' filter, as disclosed in, for example, WO 2006/059134) - may effectively and advantageously be incorporated into a recess filter, according to aspects of the present invention. The claimed filters (recess filters) may provide improved sensory characteristics, because it is possible to exercise greater control over the contact of the smoke stream with the carbon in the filter (e.g. by controlling the location of the carbon within a central 'pod' or pocket in a 'Smooth Core' filter, or on the periphery of the plugwrap in an 'Active Patch' filter) and then allowing the smoke streams to circulate and mingle within the recess prior to entering the smoker's mouth and impinging on their palate. The use, as a "base rod" within a recess filter, of a single longitudinally extending core of filtering material having an additive-free end, can considerably reduce the complexity and cost of manufacture of recess filters containing an additive - e.g. carbon recess filters. This is because there is the need to only cut and align a single filter component rather than two or more segments as with conventional carbon recess filters.

The use of a rod shaped core of tobacco smoke filtering material and an additive (e.g. particulate additive) bearing wrapper engaged around the rod shaped core in a superslim recess filter may enable higher carbon weights to be used than for conventional superslim carbon recess filters, while maintaining a satisfactory pressure drop and smoking experience. The filtering material may be for example any of those materials (usually filamentary, fibrous, web or extruded) conventionally employed for tobacco smoke filter manufacture. The filtering material may be natural or synthetic filamentary tow, e.g. of cotton or plastics such as polyethylene or polypropylene, or cellulose acetate filamentary tow. It may be, for example, natural or synthetic staple fibres, cotton wool, web material such as paper (usually creped) and synthetic non-wovens, and extruded material (e.g. starch, synthetic foams).

The additive may be a particulate additive. The particulate additive may any particulate additive suitable for use in a tobacco smoke filter - e.g. activated carbon, zeolite, ion exchange resin (e.g. a weakly basic anion exchange resin), sepiolite, silica gel, alumina, molecular sieves, carbonaceous polymer resins and diatomaceous earths. The particulate additive may be a mixture of two, or more, materials. The additive may include a flavourant - e.g. menthol - e.g. the additive may be sepiolite granules to which menthol has been applied. If the longitudinally extending extending core of tobacco smoke filtering includes fully enclosed (e.g. embedded) pocket(s) of additive embedded therein, the additive may be a particulate additive such as activated carbon (see above), which is for example enclosed within the filtering material as a discrete pocket or pod of particles of particulate additive which is substantially separate from, and fully enclosed within, the filtering material. In another example, the fully enclosed (e.g. embedded) pocket(s) of additive may be a frangible capsule or capsules, or one or a plurality of frangible microcapsules. The capsule(s) or microcapsule(s) may contain a variety of media - e.g. a flavourant and/or a liquid, solid or other material e.g. to aid smoke filtration. The use of capsules or microcapsules is well known in the art.

The tobacco smoke filter may be of length 15 to 40 mm, e.g. 7 to 35 mm, e.g. 20 to 30 mm. The recess section of the filter tip (that is, the length by which the second end of the outer wrapper extends beyond the second end of the core around which is engaged to define the cavity at the second (e.g. mouth) end of the filter) may have a length 3 to 10 mm, and is most preferably of length 4 to 6 mm. The single longitudinally extending core of tobacco smoke may be of length 10 to 30 mm, e.g. 14 to 27 mm, e.g. 17 to 25 mm. The tobacco smoke filter may be of circumference 14 to 28 mm, for example 16 to 26 mm, for example 16 to 17 mm or 24 to 25 mm. The final filter cigarette may be ventilated or non- ventilated and of any circumference range traditionally used in smoking products (e.g. c. 14 to c. 28 mm circumference). The outer wrapper may be paper, e.g. plugwrap paper, e.g. stiff plugwrap paper.

The outer wrapper may be porous or non porous. The outer wrapper may be a paper of basis weight from about 40 to about 120 g/m² The outer wrapper may be of basis weight from about 80 to about 120 g/m², for example a basis weight of around 100 g/m², e.g. for a recess filter of standard (c. 24-25 mm) circumference. For slim or superslim recess filters (e.g. down to around 16-17 mm circumference), the outer wrapper may be a plugwrap paper of a lower basis weight, e.g. around 50 g/m².

The outer wrapper of basis weight from about 40 to about 120 g/m² can overcome a potential disadvantage associated with 'Active Patch' filters, that it can be possible to feel the presence of carbon granules adhered to the inner surface of the additive bearing wrapper (of e.g. plugwrap paper) when handling the finished filter or cigarette. The defined filters (e.g. including outer wrapper of basis weight from about 40 to about 120 g/m²) may allow a larger granular size of particulate additive to be used (e.g. on the 'Active Patch' filter component), because the presence of such particles cannot be felt, or is less likely to be felt, on the outside of the finished cigarette (because of the increased "stiffnesss" of a wrapper of heavier basis weight).

In a filter cigarette according to the invention, a filter of the invention (or a filter which includes a filter element of the invention) is joined to a wrapped tobacco rod with one end of the filter towards the tobacco. The filter may, for example, be joined to the wrapped tobacco rod by ring tipping [which engages around just the adjacent ends of the (wrapped) filter and rod to leave much of the filter wrap exposed] or, more preferably, by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod). The cigarette may include a tipping overwrap (of e.g. a stiff tipping paper) in conjunction with the outer wrapper of the filter to give the desired (e.g. further increased) stiffness to the final recess filter cigarette. Any filter or filter cigarette according to the invention may be unventilated, or may be ventilated by methods well known in the art, e.g. by use of a pre-perforated or air- permeable wrapper (plugwrap), and/or laser perforation of wrapper (plugwrap) and tipping overwrap. A ventilating full tipping overwrap may likewise be inherently air-permeable or provided with ventilation holes, and in ventilated products where both filter plugwrap and tipping overwrap are present ventilation through the overwrap will usually be in register with that through the plugwrap. Ventilation holes through a filter plugwrap, or through a tipping overwrap, or through both simultaneously, may be made by laser perforation during filter or filter cigarette production.

Where ventilation in a filter or filter cigarette according to the invention is localised longitudinally of the product, this localisation is preferably to one or two regions selected from upstream of, downstream of, and in register with the or a pocket (or patch or portion) of first additive, depending upon the ventilation and filtering performances required.

Ventilation upstream of and/or in register with a pocket of first additive is frequently preferred. There may be ventilation between portions (or pockets or patches) of second additive when two or more are present.

According to the invention in a further aspect there is provided a multiple rod comprising a plurality (e.g. 2, 4, 6 etc.) of filters (or filter elements) as described above and/or herein integrally joined end-to-end in a mirror image relationship.

The present invention will now be illustrated with reference to the following

Examples and the attached drawings in which FIGURE 1 schematically illustrates a recess filter according to an embodiment of the invention; FIGURE 2 schematically illustrates a recess filter according to a second embodiment of the invention; FIGURE 3 schematically illustrates a recess filter according to a further embodiment of the invention; FIGURE 4 schematically illustrates a recess filter according to a different further embodiment of the invention; and FIGURE 5 schematically illustrates a recess filter according to a different still further embodiment of the invention. Examples

Figure 1 shows an 'Active Patch' recess filter 1 comprising an outer wrapper 3 of plugwrap paper of basis weight 100 g/m² engaged around a single longitudinal extending core of tobacco smoke filtering material 5. The first end of the outer wrapper 3a is substantially flush with first end 5a of the core 5 around which it is engaged, and second end of the outer wrapper 3b extends beyond second end 5b of the core 5 around which is engaged to define a cavity 6, a recess at the second (mouth) end of the filter. It will be appreciated that it is the radially inner face of the outer wrapper 3 which extends beyond the second end of core 5b, which defines, with the second end of the longitudinally extending core 5b, the tubular cavity (recess) 6, located at the second end of the filter. The single longitudinally extending core of tobacco smoke filtering material 5 is an "Active Patch" filter element, such as are well known in the art, for example as disclosed in GB 2261152. The core 5 comprises a rod shaped core 7 of tobacco smoke filtering material in the form of cellulose acetate tow, and an additive (particulate additive) bearing wrapper 9 engaged around the rod shaped core, the additive bearing wrapper 9 having additive in the form of activated carbon granules adhered to a portion or patch 11 of the radially inner face thereof, with said additive bearing wrapper being free of additive around its circumference at the second end 9a of the core. The filter 1 is of 27mm length, of which the cavity 6, or recess, at the second end is of length 6mm. The patch 11 is centrally located between the two ends of core 7; the core 7 has both ends free of additive. The active patch filter element may, for example, be made by the method disclosed in GB 2261152. Methods for the inclusion of filter elements into recess filters are well known in the art, and the skilled man would readily understand how to include an "Active Patch" filter element in a recess filter, to provide a recess filter according to the present invention.

Figure 2 shows a similar filter, and the reference numerals are the same as those for the embodiment of Fig 1. In the embodiment of Fig 2, the carbon patch 11 extends to the first (tobacco) end of the core 5a, thereby enabling a higher weight of carbon to be carried within the filter, but still presenting a clean end (i.e. end of the core 5b) to the smoker. Figure 3 again shows a similar filter, and the reference numerals are the same as those for the embodiments of Figs 1 and 2. Fig 3 shows a 'split patch' variant, having two patches 11a and 11 b, separated by a gap 12 (where carbon granules are not present on the plugwrap); the gap 12 is positioned to coincide with the location of the ventilation holes (not shown) on the finished cigarette.

Figures 4 and 5 show examples of 'Smooth Core' recess filters. Figure 4 shows a tobacco smoke filter 101 comprising an outer wrapper 103 of plugwrap paper of basis weight 100 g/m² engaged around a single longitudinal extending core of tobacco smoke filtering material 105. The single longitudinal extending core of tobacco smoke filtering material 105 is a pod filter, for example as disclosed in WO 2006/059134. The core 105 comprises a rod shaped core 107 of tobacco smoke filtering material in the form of cellulose acetate tow, having fully enclosed (e.g. embedded) therewithin a pocket 199 of additive in the form of particles of activated carbon. The first end 103a of the outer wrapper 103 is substantially flush with a first end 105a of the core around which it is engaged, and a second end 103b of the outer wrapper extends beyond a second end 105b of the core around which is engaged to define a cavity 106, a recess at the second (mouth) end of the filter. It will be appreciated that it is the radially inner face of the outer wrapper 103 which extends beyond the second end of core 105b, and defines, with the second end of the longitudinally extending core 105b, the tubular cavity (recess) 106, at the second, or mouth, end of the filter. The filter 101 is of 27mm length, of which the cavity 106, or recess, at the second end is of length 6mm. The pocket 199 is located towards the first or tobacco end of core 107, but it will be appreciated that core 107 has both ends free of additive (because it the additive is fully embedded within the core); the additive is invisible from the second or mouth end of the filter. The pod filter element 107 may, for example, be made by the method disclosed in WO 2006/059134. Methods for the inclusion of filter elements into recess filters are well known in the art, and the skilled man would readily understand how to include a pod filter element in a recess filter, to provide a recess filter according to the present invention. Figure 5 shows a filter similar to that of Figure 4, and the reference numerals are the same as those for the embodiment of Fig 5. In Figure 5 the pocket 199 is located centrally between the second (mouth) and first (tobacco) ends of core 107; again, it will be appreciated that core 107 has both ends free of additive (because it the additive is fully embedded within the core) and therefore the additive is invisible from the second or mouth end of the filter. Figures 4 and 5 demonstrate that the position and size/weight of the granular pocket 199 can be varied to suit different cigarette design requirements.

Claims

1. A tobacco smoke filter or filter element comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material, wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged, to define a cavity at the second end of the filter; the filter or filter element further comprising an additive distanced from the second end of the outer wrapper and/or core.

2. A filter or filter element according to claim 1 wherein the single longitudinally extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material having fully enclosed therewithin at least one pocket of additive.

3. A filter or filter element according to claim 1 wherein the single longitudinally extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material and an additive bearing wrapper engaged around the rod shaped core, the additive bearing wrapper having additive adhered to one or more portion(s) of the radially inner face thereof with said additive bearing wrapper being free of additive around its circumference at the second end of the core.

4. A filter or filter element according to claim 1 wherein the outer wrapper has additive adhered to one or more portion(s) of the radially inner face thereof with said outer wrapper being free of the additive around its circumference at the second end of the wrapper.

5. A tobacco smoke filter comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material; wherein the single longitudinal extending core of tobacco smoke filtering material comprises a rod shaped core of tobacco smoke filtering material having fully enclosed therewithin at least one pocket of additive; wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged to define a cavity at the second end of the filter.

6. A tobacco smoke filter comprising an outer wrapper engaged around a single longitudinal extending core of tobacco smoke filtering material; wherein a first end of the outer wrapper is substantially flush with a first end of the core around which it is engaged, and a second end of the outer wrapper extends beyond a second end of the core around which is engaged to define a cavity at the second end of the filter; the single longitudinally extending core of tobacco smoke filtering material comprising a rod shaped core of tobacco smoke filtering material and an additive bearing wrapper engaged around the rod shaped core, the additive bearing wrapper having additive adhered to one or more portion(s) of the radially inner face thereof with said additive bearing wrapper being free of additive around its circumference at the second end of the core.

7. A filter or filter element according to any preceding claim wherein the filtering material is one or more of natural or synthetic filamentary tow, e.g. cotton or plastics such as polyethylene or polypropylene, cellulose acetate filamentary tow, natural or synthetic staple fibres, cotton wool, a web material such as paper (e.g. creped paper), synthetic non- woven material, and extruded material (e.g. starch, synthetic foams).

8. A filter or filter element according to any preceding claim wherein the additive is a particulate additive.

9. A filter or filter element according to any preceding claim wherein the particulate additive is activated carbon, zeolite, ion exchange resin (e.g. a weakly basic anion exchange resin), sepiolite, silica gel, alumina, molecular sieve, carbonaceous polymer resin, a diatomaceous earth, or a mixture of two, or more, of these additives.

10. A filter or filter element according to claim 2 or 5 wherein the additive in the fully enclosed pocket(s) of additive is a frangible capsule or capsules, or one or a plurality of frangible microcapsules.

11. A filter or filter element according to any preceding claim wherein the outer wrapper is paper, e.g. plugwrap paper.

12. A filter or filter element according to any preceding claim wherein the outer wrapper is paper having a basis weight from about 40 to about 120 g/m².

13. A tobacco smoke filter substantially as hereinbefore described with reference to any of the attached drawings.

14. A filter cigarette comprising a filter according to any preceding claim joined to a wrapped tobacco rod with the first end of the core towards the tobacco.

15. A multiple rod comprising a plurality (e.g. 2, 4, 6 etc.) of filters (or filter elements) according to any of claims 1 to 13 integrally joined end-to-end in a mirror image relationship.