FILTER FOR A SMOKING ARTICLE

Description

[0001] The present invention relates to a filter for a smoking article.

[0002] As used herein, the term 'smoking article' includes smokeable products such as cigarettes, cigars and cigarellos, whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products, but is not limited thereto.

[0003] A smoking article, such as a cigarette is typically provided with a filter for the gaseous flow drawn by a smoker which is connected to a tobacco rod. The filter is commonly made of cellulose acetate tow. A user ignites one end of the tobacco rod and draws a gaseous flow, such as smoke in through the filter. The filter traps some of the smoke components produced by the burning tobacco rod.

[0004] Smoking articles, and filters therefore, can vary significantly from one market to another as a result of many different factors including consumer preference and tradition. In certain markets there is a preference for a filter having a recess at the mouth end, which may be used to lengthen the filter as a whole. Such a recess filter is known from US 7 243 659 B1.

[0005] The recess is achieved by overwrapping the plug of filtration material at the mouth end of the filter. However, a disadvantage of providing a filter with a recess is that it elongates the length of the filter and therefore the smoking article.

[0006] In order to retain the filter and hence the smoking article at a standard length there is a need to shorten the filter so that the relative lengths of the tobacco rod section and the filter section of the smoking article can be maintained. However, if a conventional plug of filtration material is shortened then the filter will be less effective at filtering the gaseous flow therethrough than a conventional length filter without a recess. Therefore, there is a need to provide a filter with a recess that does not increase the size of the filter section.

[0007] The present invention seeks to provide a filter for a smoking article which overcomes or substantially alleviates the problems associated with conventional filters for smoking articles described above.

[0008] WO00/00047A1 discloses a filter for a smoking article having the features recited in the preamble of claim 1. A filter according to the present invention is characterised by the features referred to in the characterising portion of claim 1.
Conveniently, the wrapper extends circumferentially around the first and second filter portions and extends longitudinally from one end of the first filter portion to form the recess section.

[0009] Preferably, the longitudinally extending plug comprises a filtration material.
Advantageously, the particulate material extends to an end of the second filter portion immediately adjacent the first filter portion.

[0010] Preferably, the particulate material extends over a full longitudinal length of the second section.
The plug may further comprise a particulate material interspersed in the filtration material, which may be adsorbent.
The particulate material may be activated carbon.
In one embodiment, the first filter portion comprises a filtration material.
According to another aspect of the invention, there is provided a smoking article including a filter according to the invention.

[0011] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIGURE 1 illustrates a perspective view of a smoking article including a rod of smokeable material and a filter according to the present invention;

FIGURE 2 illustrates a perspective view of a filter element for a smoking article according to an embodiment of the present invention;

FIGURE 3 illustrates a cross-sectional elevational side view of the filter element shown in Figure 2; and

FIGURE 4 illustrates a surface of a wrapper having the particulate material applied thereto.

[0012] Referring now to the drawings, there is shown in Figure 1 a smoking article 1 in the form of a cigarette, which includes a filter 2 in accordance with one aspect of the present invention. Even though Figure 1 shows the smoking article as a cigarette, it should be appreciated that the smoking article 1 may take other forms, such as a cigar or cigarillo etc., which may also include the filter 2 according to the invention.

[0013] Referring to Figure 1, the smoking article 1 comprises a generally cylindrical paper-wrapped rod of smokeable material 3, such as tobacco, co-axially attached to the filter 2 by tipping paper 4, which is glued around one end of the rod of smokeable material 3 and the filter 2 in a conventional manner, and so no further discussion of the tipping paper will be given herein.

[0014] An embodiment of the filter 2 attached to the rod of smokeable material 3 is shown in Figures 2 and 3. In this embodiment, the filter 2 comprises a filter section 5 about 22mm in length, which includes first and second filter portions 6,7. The filter section 5 typically has a diameter of between 7.5mm to 8mm and the first filter portion 6 includes a wrapper 8 circumscribed therearound which, in this embodiment is a plugwrap material, although the wrapper is not limited thereto. The wrapper or plugwrap 8 is longer than the filter section 5 and overhangs the filter section 5 at a mouth end 9 of the filter 2 to create a recess section 10 having a depth of approximately 5mm. The length of the overhang of the plugwrap 8 and hence the depth of the recess 10 is designated in Figure 2 by the reference character 'x'. The filter section 5 and the recess section 10 together form the filter 2.

[0015] The plugwrap 8 has a high base weight, for example 100g/m², to provide rigidity to the recess section 10. The plug wrap 8 forming the recess section 10 at the mouth end of the smoking article is made of heavyweight plugwrap to ensure that the recess is maintained and does not easily collapse due to the absence of any supporting filter material.

[0016] The first filter portion 6 is disposed between the recess section 10 and the second filter portion 7, such that the first filter portion 6 is closer to the mouth end 9 of the filter 2 than the second filter portion 7 and separates the second filter portion 7 from the recess section 10. The second filter portion 7 is disposed between the first filter portion 6 and the rod of smokeable material 3 when the filter 2 is disposed in the smoking article 1.

[0017] The first filter portion 6 comprises a plug of filtration material about which the plugwrap 8 is circumscribed. The plug of filtration material is formed of fibrous cellulose acetate, although it will be understood that any conventional filtration material may be used. The first filter portion 6 has first and second circular end faces 13,14.

[0018] The second filter portion 7 comprises a plug 15 of filtration material, such as fibrous cellulose acetate, and a particulate material 16, such as carbon or activated carbon interspersed in said filtration material. The particulate material 16 in the central plug 15 is optional (although in some embodiments is preferred).
The second filter portion 7 further comprises a wrapper 17, preferably a plugwrap material, and having a particulate material 18 such as carbon or activated carbon adhered on an inner surface thereof. The wrapper 17 circumferentially envelopes the plug 15 about the longitudinal axis extending through the filter 2, and has a lapped and seamed region. Alternatively, the wrapper 17 is a split wrapper bonded to the plug 15. The second filter portion 7 has first and second circular end faces 19,20.

[0019] The surface of the wrapper 17 having particulate material 18 adhered thereto is shown in Figure 4. The particulate material 18 is disposed in separate regions 21 spaced from each other on the inner surface of the wrapper 17. Each of the separate regions 21 of particulate material 18 extend longitudinally along the wrapper 17, however the particulate material 18 extends only partially across the width of the wrapper 17 and longitudinal edges 22 of the wrapper 17 are free from particulate, thus providing a lapped and stuck seam free from particulate material when formed around the plug 15. When the wrapper 17 is formed around the plug by conventional means, the particulate material 18 is disposed in two separate regions spaced diametrically opposite each other.
It will be understood that the number of separate regions 21 of particulate material 18 disposed on the wrapper 17 is not limited to two regions, and that other arrangements of particulate material 18 may be used. For example, three, four, five or six separate regions spaced from each other on the inner surface of the wrapper 17 may be used. In such arrangements, the regions are evenly and symmetrically positioned around the longitudinal axis extending through the second filter portion 7. However, other spacings may be used. Further, the regions on a particular wrapper may or may not be all of equal width, and may or may not be of equal width with the gaps between the regions. Similarly, the gaps between the regions may not be of equal width.
An advantage of the symmetrical arrangement is that it obviates bending or curving of the filter element that can arise in a non-symmetric arrangement if the adhered particulate material pulls on and distorts the wrapper and hence the filter.
The particulate material 18 disposed on the wrapper 17 is selected from a group of relatively high surface area of materials capable of adsorbing smoke constituents without a high degree of specificity, although the particulate material is not limited thereto. Suitable general adsorbents can be selected from the group consisting of carbon, activated carbon, activated charcoal, activated coconut carbon, activated coal-based carbon or charcoal, zeolite, silica gel, meerschaum, aluminium oxide (activated or not), carbonaceous resin or combinations thereof. The particulate mixture used may be a single substance or a mixture, and/or may be in a mixture with another material.
The filter 2 is arranged with the recess section 10 disposed at the mouth end 9 of the smoking article 1, which extends from the first end 13 of the first filter portion 6. The recess section 10 is defined by a circumferentially extending inner surface of the plugwrap 8 extending from the first filter portion 6 and the first end 13 of the first filter portion 6, and has an opening 23 at the mouth end 9. The first end 13 of the first filter portion 6 is visible to a user through the opening 23.

[0020] The second end 14 of the first filter portion 6 abuts the first end 19 of the second filter portion 7, such that the opening 23 of the recess 10 and the second end 20 of the second filter portion 7 define the opposing ends of the filter 2.

[0021] An advantage of the above arrangement is that the provision of the particulate material 18 disposed in a circumferential region of the second filter portion 7 increases the effectiveness of the filter section 5 at filtering the gaseous flow therethrough. Therefore, the filter 2 may be shortened without negating the effectiveness of the filter section 5 at filtering the gaseous flow therethrough and so there is provision to provide a filter with a recess section without lengthening the filter 2.
The provision of the first filter portion 6 between the recess section 10 and the second filter portion 7 allows the second filter portion 7 to be upstream of the filtration material of the first filter portion 6 and prevents the particulate material 18 disposed in a circumferential region of the second filter portion 7 from being dislodged or displaced therefrom and entering the recess section 10. Such loose particulate material 18 could then come into contact with a user. Furthermore, with the above arrangement the particulate material 18 disposed in a circumferential region of the second filter portion 7 and particulate material 16 interspersed in the filtration material of the plug 15 of the second filter portion 7 is not visible to the user.

[0022] In use, a user inserts the mouth end 9 of the smoking article into their mouth and lights the paper-wrapped rod 3 of smokeable material at the distal end of the smoking article to the mouth end 9 such that said end burns. The filter 2 is located at the mouth end 9 of the smoking article 1 such that a gaseous flow, comprising smoke drawn from the rod of smokeable material 3, moves through the filter 2 before entering the mouth of the user.
Although in the above embodiment the first filter portion 6 and the second filter portion 7 are shown to have individual plugwraps 8,17, it will be understood that in an alternative embodiment the filter comprises a single plugwrap which extends over the entire filter section 5, joins the first and second filter portion 6,7 and forms the recess section 10. In such an embodiment, the particulate material 18 extends only partially along said plugwrap so that the particulate material extends over the second filter portion 7 only and does not extend over the first filter portion 6.
Although in the above embodiments the filter section 5 is formed from two discrete filter portions, in an alternative embodiment the first and second filter portions 6,7 are integrally formed.
Although in the above embodiment the recess section is formed by the plugwrap extending beyond the plug of filtration material, it will be understood that the invention is not limited thereby and that in an alternative embodiment the recess may be formed by the tipping paper.
Although embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that variations may be made to the above exemplary embodiments that lie within the scope of the following claims.

Claims

1. A filter for a smoking article comprising a filter section (5), a recess section (10) and a wrapper (17), the recess section (10) being defined at a mouth end (9) of the filter and the filter section (5) being longitudinally aligned with and adjacent to the recess section (10) and comprising first and second filter portions (6, 7), the first filter portion (6) being disposed between the recess section (10) and the second filter portion (7), the second filter portion (7) comprising a longitudinally extending plug (15) around which the wrapper (17) is engaged, characterised in that a particulate material (18) is adhered to the surface of the wrapper (17), and in that the particulate material (18) adhered to the surface of the wrapper (17) is disposed in two or more regions spaced circumferentially from one another.

2. A filter according to claim 1, wherein the wrapper (8,17) extends circumferentially around the first and second filter portions (6,7) and extends longitudinally from one end of the first filter portion (6) to form the recess section (10).

3. A filter according to claims 1 or 2, wherein the longitudinally extending plug (15) comprises a filtration material.

4. A filter according to any preceding claim, wherein the particulate material (18) extends to an end of the second filter portion (7) immediately adjacent the first filter portion (6).

5. A filter according to any preceding claim, wherein the particulate material (18) extends over a full longitudinal length of the second filter portion (7).

6. A filter according to claim 3, wherein the plug (15) further comprises a particulate material (16) interspersed in the filtration material.

7. A filter according to any preceding claim, wherein the particulate material is adsorbent.

8. A filter according to claim 7, wherein the particulate material is activated carbon.

9. A filter according to any preceding claim, wherein the first filter portion (6) comprises a filtration material.

10. A smoking article comprising a filter according to any preceding claim.

Ansprüche

1. Filter für einen Rauchartikel, umfassend einen Filterabschnitt (5), einen Aussparungsabschnitt (10) und eine Umhüllung (17), wobei der Aussparungsabschnitt (10) an einem Mundende (9) des Filters definiert ist und der Filterabschnitt (5) in Längsrichtung auf den Aussparungsabschnitt (10) ausgerichtet ist und diesem benachbart ist und einen ersten und einen zweiten Filterteilabschnitt (6, 7) umfasst, wobei der erste Filterteilabschnitt (6) zwischen dem Aussparungsabschnitt (10) und dem zweiten Filterteilabschnitt (7) angeordnet ist, wobei der zweite Filterteilabschnitt (7) einen sich in Längsrichtung erstreckenden Stab (15) umfasst, um den sich die Umhüllung (17) im Eingriff befindet, dadurch gekennzeichnet, dass ein partikelförmiges Material (18) an die Oberfläche der Umhüllung (17) geklebt ist, und dadurch, dass das an der Oberfläche der Umhüllung (17) klebende partikelförmige Material (18) in zwei oder mehr in Umfangsrichtung voneinander beabstandeten Regionen angeordnet ist.

2. Filter nach Anspruch 1, wobei sich die Umhüllung (8, 17) in Umfangsrichtung um den ersten und den zweiten Filterteilabschnitt (6,7) erstreckt und sich in Längsrichtung von einem Ende des ersten Filterteilabschnitts (6) erstreckt, um den Aussparungsabschnitt (10) zu bilden.

3. Filter nach Anspruch 1 oder 2, wobei der sich in Längsrichtung erstreckende Stab (15) ein Filtrationsmaterial umfasst.

4. Filter nach einem der vorangehenden Ansprüche, wobei sich das partikelförmige Material (18) zu einem dem ersten Filterteilabschnitt (6) unmittelbar benachbarten Ende des zweiten Filterteilabschnitts (7) erstreckt.

5. Filter nach einem der vorangehenden Ansprüche, wobei sich das partikelförmige Material (18) über eine volle Länge in Längsrichtung des zweiten Filterteilabschnitts (7) erstreckt.

6. Filter nach Anspruch 3, wobei der Stab (15) weiter ein partikelförmiges Material (16) umfasst, mit dem das Filtrationsmaterial durchsetzt ist.

7. Filter nach einem der vorangehenden Ansprüche, wobei das partikelförmige Material absorptionsfähig ist.

8. Filter nach Anspruch 7, wobei es sich bei dem partikelförmigen Material um Aktivkohle handelt.

9. Filter nach einem der vorangehenden Ansprüche, wobei der erste Filterteilabschnitt (6) ein Filtrationsmaterial umfasst.

10. Rauchartikel, der einen Filter nach einem der vorangehenden Ansprüche umfasst.

Revendications

1. Filtre pour article à fumer comprenant une section filtre (5), une section en renfoncement (10) et une enveloppe (17), la section en renfoncement (10) étant définie au niveau d'une extrémité buccale (9) du filtre et la section filtre (5) étant alignée longitudinalement, et adjacente, à la section en renfoncement (10) et comprenant des première et seconde parties de filtre (6, 7), la première partie de filtre (6) étant disposée entre la section en renfoncement (10) et la seconde partie de filtre (7), la seconde partie de filtre (7) comprenant un bout-filtre s'étendant longitudinalement (15) autour duquel l'enveloppe (17) est appliquée,
caractérisé en ce qu'un matériau particulaire (18) est collé à la surface de l'enveloppe (17), et en ce que le matériau particulaire (18) collé à la surface de l'enveloppe (17) est disposé dans deux ou plusieurs régions espacées circumférentiellement les unes des autres.

2. Filtre selon la revendication 1, dans lequel l'enveloppe (8, 17) s'étend circonférentiellement autour des première et seconde parties de filtre (6, 7) et s'étend longitudinallement depuis une extrémité de la première partie de filtre (6) pour former la section en renfoncement (10).

3. Filtre selon la revendication 1 ou 2, dans lequel le bout-filtre s'étendant longitudinalement (15) comprend un matériau de filtration.

4. Filtre selon l'une quelconque des revendications précédentes, dans lequel le matériau particulaire (18) s'étend jusqu'à une extrémité de la seconde partie de filtre (7) immédiatement adjacente à la première partie de filtre (6).

5. Filtre selon l'une quelconque des revendications précédentes, dans lequel le matériau particulaire (18) s'étend par-dessus toute une longueur longitudinale de la seconde partie de filtre (7).

6. Filtre selon la revendication 3, dans lequel le bout-filtre (15) comprend en outre un matériau particulaire (16) dispersé dans le matériau de filtration.

7. Filtre selon l'une quelconque des revendications précédentes, dans lequel le matériau particulaire est adsorbant.

8. Filtre selon la revendication 7, dans lequel le matériau particulaire est du charbon actif.

9. Filtre selon l'une quelconque des revendications précédentes, dans lequel la première partie de filtre (6) comprend un matériau de filtration.

10. Article à fumer comprenant un filtre selon l'une quelconque des revendications précédentes.

Drawing