Filter for a Smoking Article

Abstract

The invention provides a filter element for a smoking article. The filter element comprises a plug of filter material, a tobacco core extending substantially longitudinally through the plug of filter material, and wrapping means wrapped around at least a portion of a longitudinally extending surface of the tobacco core. The filter element can be used in a variety of smoking articles.

Description

The present invention relates to filters for smoking articles.

It is well known that filtration of smoke in a smoking article, such as a cigarette may affect the taste and flavour characteristics of a product when smoked. Filters commonly include adsorbent materials, such as activated carbon, to reduce certain components of the smoke during smoking. However, activated carbon in a filter can adversely affect the taste and/or flavour characteristics of a cigarette.

Therefore, in a first aspect of the invention, there is provided a filter element for a smoking article, the filter element comprising a plug of filter material, a tobacco core extending substantially longitudinally through the plug of filter material, and wrapping means wrapped around at least a portion of a longitudinally extending surface of the tobacco core.

The inventors have found that the provision of the substantially longitudinal tobacco core improves the flavour of smoke (which comprises gas and particulate matter) that is inhaled by a smoker. Furthermore, the provision of the wrapping means ensures that the tobacco remains within the core within the plug of filter material, and that the smoke is directed therealong.

Preferably, the tobacco core extends substantially longitudinally between mutually opposing end faces of the plug of filter material. Preferably, the tobacco core extends in a direction which is substantially parallel to a side face of the plug of filter material, which side face is preferably substantially perpendicular to one or both end faces. Preferably, the tobacco core extends through an inner portion of, and is surrounded by, the filter material. Preferably, the tobacco core extends through substantially the centre of the plug of filter material.

Advantageously, the tobacco core is disposed in close proximity with the path of the gaseous flow as it moves through the filter element, and is therefore able to affect various characteristics of the gaseous flow before the flow reaches the smoker's mouth. Furthermore, because the tobacco core is disposed substantially longitudinally within the plug of filter material, it does not adversely affect the direction or rate of gaseous flow, and so the smoker does not detect a significant difference in the resistance to draw therethrough.

The tobacco core may comprise shredded tobacco, powdered tobacco, reconstituted tobacco, tobacco stem, tobacco fibres, tobacco sheet and/or cut tobacco. However, preferably the tobacco core comprises cut tobacco lamina, cut tobacco blend and/or tobacco stem.

The tobacco core may form a tobacco rod of any cross-section. For example, the tobacco core may form a tobacco rod of triangular or square cross-section. However, preferably the tobacco core forms a tobacco rod of circular cross-section. Hence, the tobacco core may be substantially cylindrical in shape.

The wrapping means may be substantially permeable to air, such that smoke may pass therethrough in to the tobacco core as a smoker inhales. The wrapping means may be formed of any conventional paper material. For example, the wrapping means may comprise plugwrap or paper, for example cigarette paper. The wrapping means may be perforated. The wrapping means may be a reconstituted wrapper, or a tobacco sheet wrapper. The wrapping means may comprise tobacco leaf. The wrapping means may be impervious.

The wrapping means may be in contact with substantially all of the longitudinally extending side surface of the tobacco core. Preferably, the wrapping means circumscribes the tobacco. However, the wrapping means may not be disposed around at least one end face, and preferably each end face, of the tobacco core.

The tobacco core may comprise, or be derived from, at least a longitudinal section of a tobacco rod of a smoking article, such as a cigarette, cigar or cigarillo, or the like, i.e. the smokeable section of the smoking article. It will be appreciated that the longitudinal section of the tobacco rod will comprise a wrapper, such as cigarette paper or the like, and that this wrapper forms the wrapping means of the filter element of the first aspect.

It is preferred that the diameter of the longitudinal section of the tobacco rod is less than the diameter of the plug of filter material, and hence filter element according to the first aspect, such that it forms the tobacco core extending therethrough. Standard-sized cigarettes tend to have a diameter of about 7.5 mm to about 9.5 mm (preferably 8-12 mm), whereas slim-sized cigarettes tend to have a diameter of about 2-6 mm. Therefore, because the diameter of the tobacco rod of a slim-sized cigarette is less than that of a standard-sized cigarette, the inventors envisage using a longitudinal extending section of the tobacco rod of a slim-sized smoking article to form the wrapped tobacco core of a filter element for use in filter of a standard-sized smoking article. The inventors believe that they are the first to consider using the tobacco rod section of a slim-sized smoking article to form a tobacco core in the filter of a standard-sized smoking article.

Hence, in a second aspect of the invention, there is provided a filter element for a smoking article, the filter element comprising a plug of filter material, and a tobacco core extending substantially longitudinally through the plug of filter material, wherein the tobacco core comprises, or is derived from, a longitudinal section of a tobacco rod of a smoking article.

The tobacco core may comprise, or be derived from, a longitudinal section of a tobacco rod of a slim-sized smoking article. By using a longitudinal section of a wrapped tobacco rod of a slim-sized smoking article, the manufacture of standard-sized filter elements may be facilitated. Furthermore, advantageously, it is easier to change the tobacco in the longitudinal core extending through the filter material, thereby providing different tobacco styles and tastes in a range of filter elements.

It will be appreciated that there are many different types of slim-sized smoking articles from which the tobacco core may be derived, and that the dimensions of such slim-sized smoking articles varies from brand to brand. However, the tobacco core in the filter element of the first or second aspect may be between 3 mm and 8 mm in diameter, preferably between 3 mm and 7 mm in diameter, more preferably between 3.5 mm and 6.5 mm in diameter, and most preferably between 4 mm and 6 mm in diameter.

Once prepared, the tobacco core may be encased by filter material to form the filter element of the first or second aspect. The plug of filter material may comprise any suitable filter media, which will be known to the skilled technician. A preferred filter material comprises cellulose acetate. The diameter of the plug of filter material may be between 5 mm and 15 mm, preferably between 6 mm and 12 mm, more preferably between 7 mm and 10 mm, and most preferably between 7 mm and 9 mm.

Preferably, the ratio of the diameter of the plug of filter material to the diameter of the tobacco core is between 0.5:1 and 10:1, more preferably between 1:1 and 5:1, even more preferably between 1:1 and 3:1, and most preferably between 1.5:1 and 2:1.

The filter element of the first or second aspect may comprise a flavourant. In embodiments where a flavourant is used, the flavourant may be incorporated in the plug of filter material. However, preferably the flavourant is incorporated in the tobacco core. For example, flavourant may be sprayed onto the tobacco material prior to formation into a rod.

It will be appreciated that the filter element according to the first or second aspect may be used in the manufacture of a filter, for use in a smoking article.

Hence, according to a third aspect of the invention, there is provided a filter for a smoking article, the filter comprising a filter element according to the first or second aspect.

The filter of the third aspect may comprise a plurality of filter elements according to the first or second aspect, in which a tobacco core extends through a plug of filter material.

For example, the filter may comprise 2, 3, 4, 5 or more filter elements of the first or second aspect, in which adjacent filter elements may either be connected to each other, or which elements may be separated from each other by other filter elements (which may not be in accordance with the first or second aspect).

Hence, the filter may comprise a plurality of filter elements, at least one of which is a filter element according to the first or second aspect of the invention. For example, it is envisaged that, in one embodiment, in addition to comprising one or more filter elements according to the first or second aspect (ie. containing the tobacco core), the filter of the third aspect may also comprise an adsorbent filter element, which element comprises an adsorbent material. The adsorbent filter element is provided to adsorb and, hence, reduce certain components of the smoke during smoking. The adsorbent filter element may comprise a plug of filter material in which the adsorbent material is dispersed. The filter material may be cellulose acetate. A preferred adsorbent material is activated carbon. The activated carbon may be in the form of granular activated carbon, which is preferably distributed substantially throughout the volume of the plug of filter material. Preferably, the adsorbent filter element does not include a tobacco core.

In another embodiment, in addition to comprising one or more filter elements according to the first or second aspect (ie. containing the tobacco core), the filter of the third aspect may also comprise a filter element, which comprises filter material (such as, cellulose acetate), and which does not include a tobacco core or adsorbent material.

The filter may comprise at least two, and preferably at least three filter elements, provided that at least one filter element is in accordance with the first or second aspect. Preferably, the filter comprises a filter element according to the first or second aspect, an adsorbent filter element comprising adsorbent, and a filter element, which does not include adsorbent or a tobacco core. Preferably, multiple filter elements are arranged longitudinally of one another with the end face of one filter element abutting the end face of an adjacent filter element. It is preferred that the filter elements have substantially similar diameters. It should be appreciated that the various filter elements may be in any order in the filter, as illustrated in FIGS. 3 and 4.

The filter element of the first or second aspect, or the filter of the third aspect, may be incorporated into a smoking article.

Hence, according to a fourth aspect of the invention, there is provided a smoking article comprising a filter element according to the first or second aspect, or a filter according to the third aspect.

The smoking article preferably comprises a section or rod of smokeable material, such as tobacco. As used herein, the term “smoking article” includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products.

The section of smokeable material and the filter may be attached by tipping paper.

According to a fifth aspect of the invention, there is provided a method of manufacturing a filter element for a smoking article, the method comprising providing a tobacco core through a plug of filter material, wherein the tobacco core extends substantially longitudinally through the plug of filter material, and wherein wrapping means is wrapped around at least a portion of a longitudinally extending surface of the tobacco core.

According to a sixth aspect, there is provided a method of manufacturing a filter element for a smoking article, the method comprising providing a tobacco core through a plug of filter material, wherein the tobacco core extends substantially longitudinally through the plug of filter material, and wherein the tobacco core comprises, or is derived from, a longitudinal section of a tobacco rod of a smoking article.

The method of the sixth aspect may comprise a step of arranging a longitudinal section of a tobacco rod of a slim-sized smoking article, such that it extends substantially longitudinally through the plug of filter material. Preferably, the method of the sixth aspect comprises cutting the slim-sized tobacco rod into a section of suitable length prior to being arranged in the plug of filter material.

The methods of the fifth or sixth aspect preferably comprise a step of introducing the tobacco core into substantially the centre of the filter material. The methods may comprise using guide means to guide the tobacco core as a tow of filter material is formed therearound. The guide means may comprise a guide tube through which the tobacco core is entrained. As the core exits the guide means, it is preferably surrounded by filter material.

All of the features described herein (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying Figures, in which:

FIG. 1 shows a perspective view of a smoking article, including a rod of smokeable material, a filter in accordance with the invention, and tipping paper attaching the rod and filter together;

FIG. 2 shows a cross-sectional side view of a first embodiment of the filter according to the invention;

FIG. 3 shows a cross-sectional side view of a second embodiment of the filter; and

FIG. 4 shows a cross-sectional side view of a third embodiment of the filter.

Referring to FIG. 1, there is shown a smoking article 2, in the form of a cigarette, which includes a filter 4 in accordance with the invention. Even though the Figures show the smoking article 2 as a cigarette, it should be appreciated that the smoking article 2 may take other forms, such as cigars and cigarillos etc, which may also include the filter 4 according to the invention.

Referring to FIG. 1, the smoking article 2 comprises a generally cylindrical paper-wrapped rod 6 of smokeable material, such as tobacco, which is co-axially attached to the filter 4 by tipping paper 8, which is glued around one end of the rod 6 and the filter 4.

Referring to FIG. 2, there is shown a first embodiment of the filter 4 attached to the rod of tobacco 6. In this embodiment, the filter 4 is made up of a single, filter element 12 about 27 mm in length, which consists of a continuous plug of filter material 20 (for example, cellulose acetate) having a diameter of 9 mm. The filter element 12 has first and second generally circular end faces 22, 24, and a circumferential or longitudinally extending side surface 26 substantially perpendicular to the first and second end faces 22, 24.

As shown in FIG. 2, a cylindrical tobacco core 10 having a diameter of 3 mm extends between the two end faces 22, 24 through the plug of filter material 20. In order to retain the tobacco as a core 10, it is wrapped in plugwrap or cigarette paper 11. The paper 11 is substantially pervious to air, such that smoke can pass therethrough as a smoker inhales. The tobacco core 10 is substantially parallel with the longitudinally extending surface 26 of the filter element 12, and extends substantially through the centre of the plug of filter material 20.

In some embodiments, the tobacco core 10 is derived from a tobacco rod which would otherwise be used in the manufacture of a superslim cigarette, examples of which are sold under the trade name Vogue (dimensions: 5 mm×99 mm) or Kent Nanotek (dimensions: 5 mm×83 mm), which may be obtained from British American Tobacco Company, and available in Europe and Russia. It is envisaged that the tobacco core 10 consists of cut tobacco lamina, a cut tobacco blend or cut tobacco stems, which is wrapped in plugwrap or cigarette paper 11. Hence, the tobacco rod section of a suitable superslim cigarette consisting of a tobacco core wrapped in cigarette paper is used to form the tobacco core 10 wrapped in plugwrap 11 of the filter element 12 of the present invention.

The wrapped tobacco core 10 is approximately 3 mm in diameter, which is then introduced into the centre of the filter material 20. One method of introducing the tobacco core 10 in to the plug of filter material 20 in the manufacture of the filter element 12 as follows. The method involves entraining the tobacco core 10 through the lumen of a guide tube having a diameter of about 5 mm. Simultaneously, a supply of fibrous filter material 20 (e.g. cellulose acetate) is passed through a series of blooming rollers so that it is de-crimped. A tow of de-crimped filter material 20 is then formed around the core 10 as it exits the guide tube, to thereby form a continuous rod of filter material 20 enclosing the wrapped tobacco core 10. The rod may then be cut up in to sections of appropriate length to produce the completed filter element 12 as shown in FIG. 2. The length of the filter element 12 will depend on the type of filter 4 required. For example, a standard cigarette filter 4 is about 27 mm in length. In the embodiment shown in FIG. 2, the whole 27 mm length of the filter 4 consists of the filter element 12, such that the core 10 extends all the way along. However, FIGS. 3 and 4 illustrate other embodiments, in which the filter 4 comprises a shorter section of the filter element 12 containing the core 10 in combination with other sections, as described below.

Referring to FIG. 3, there is a shown a second embodiment of the filter 4 attached to the rod of tobacco 6. The filter 4 comprises a plurality of different discrete filter elements 12, 14, 16, each of which may have a different material composition. In this embodiment, the filter 4 includes three different filter elements 12, 14, 16. Each filter element 12, 14, 16 is generally cylindrical in shape having substantially equivalent diameters. Each filter element 12, 12, 16 is wrapped by a layer of thin sheet material in the form of a wrapper known as plugwrap (not shown), which may be formed of conventional paper materials. The filter element 16 that is farthest from the tobacco rod 6 (and which will be closest to the smoker's mouth when in use) comprises a generally cylindrical tow of filter material 20, such as cellulose acetate. The filter material 20 provides a filter through which smoke may pass as a smoker inhales on the cigarette. The filter element 12 that is disposed adjacent element 16 contains a continuous plug of filter material 20 having the tobacco core 10 extending substantially longitudinally therethrough. This filter element 12 is similar to that shown in FIG. 1, except that it does not extend along the entire length of the filter 4.

The third filter element 14 that is disposed between the filter element 12 containing the tobacco core 10 and the tobacco rod 6 comprises a plug of filter material 20, in which an adsorbent, such as activated carbon 18, has been dispersed. The activated carbon 18 may be in the form of granular activated carbon 18, which is distributed evenly throughout the volume of the plug of cellulose acetate 20 in a “Dalmatian” style, as is known in the art, and as shown in FIG. 3. Alternatively, the activated carbon 18 may be sprinkled onto a sticky exterior surface 26 of the plug of cellulose acetate 20, or adhered to the inner surface of the plugwrap surrounding the cellulose acetate, or may be adhered to a cotton thread surrounded by the plug of cellulose acetate 20 (not shown). The activated carbon 18 could also be held in a cavity surrounded by the plug of cellulose acetate 20. The activated carbon 18 is provided to improve the characteristics of the smoke that is inhaled by removing toxic chemicals.

Referring to FIG. 4, there is shown a third embodiment of the filter 4 attached to the tobacco rod 6. In this embodiment, the filter 4 includes the same three filter elements 12, 14, 16 as in the second embodiment, as described above, except that the order of the elements has been changed. As shown in FIG. 4, the filter element 16 that is farthest from the tobacco rod 6 comprises filter material 20, such as cellulose acetate, as in the second embodiment. However, in the third embodiment, the filter element 12 that is disposed adjacent element 16 contains a plug of filter material 20, in which particles of activated carbon 18 have been dispersed. Finally, the third filter element 12 disposed between element 14 and the rod of tobacco 6 contains a continuous plug of filter material 20 through which the tobacco core 10 extends. Accordingly, the positions of filter elements 12, 14 have been swapped in the second and third embodiments.

As shown in FIGS. 3 and 4, the filter elements 12, 14, 16 are arranged longitudinally of one another with the end face 22, 24 of each filter element 12, 14, 16 abutting the next. Although the three filter elements 12, 14, 16 are shown in FIGS. 3 and 4 as being substantially equal in length, it will be appreciated that they could have different lengths. For example, in FIGS. 3 and 4, the filter element 12 containing the tobacco core 10 could be 12 mm in length, and the other elements 14, 16 could be 7.5 mm each, such that the total length of the filter 4 is 27 mm. In addition, it will be appreciated that the filter 4 may comprise only the two filter elements. For example, the filter 4 may comprise the filter element 12 containing the tobacco core 10 (about 15 mm long) and the filter element 16 containing only filter material 20 (about 12 mm long), in either order. Alternatively, the filter 4 may comprise the filter element 12 containing the tobacco core 10 and the filter element 14 containing activated carbon 18, in either order.

Also, the filter 4 may comprise more than three filter elements 12, 14, 16. For example, the filter 4 may comprise first and second filter elements 16 composed of cellulose acetate, a third filter element 14 comprising cellulose acetate and activated carbon 18, and a fourth filter element 12 comprising the longitudinal tobacco core 10, as described above. It will be appreciated that the various filter elements 12, 14, 16 may be arranged in the filter 4 in a variety of alternative orders. However, in each embodiment, at least one filter element 12 containing the tobacco core 10 is included in the filter 4.

Referring to FIG. 1 once again, the filter 4 is located at a mouth-end of the smoking article 2 such that a gaseous flow, comprising smoke drawn from the rod 6 of smokeable material, moves through the filter 4 before entering the mouth of a smoker. The tobacco core 10 is located in one or more filter elements 12, and extends longitudinally between the end faces 22, 24 of a plug of filter material 20, as described in relation to FIG. 2. In this way, the tobacco core 10 is disposed in close proximity with the path of the gaseous flow as it moves through the filter 4, and is therefore able to affect various characteristics of the gaseous flow before the flow reaches the smoker's mouth.

The tobacco core 10 may, for example, affect the overall properties of the gaseous flow such that the taste and flavour of the gaseous flow are improved. One application of the tobacco core 10 is to replace a degree of the taste and flavour characteristics of the gaseous flow which may be lost as the gaseous flow moves through the filter material 20, or the activated carbon 18, which is known to affect the taste and flavour of tobacco smoke. The inventors have surprisingly found that the arrangement of the tobacco core 10 extending longitudinally through the plug of filter material 20 improves the flavour of the smoke without compromising the flow characteristics of the smoke. The invention also includes further modifications and variations falling within the scope of the claims.

Claims

1. A filter element for a smoking article, the filter element comprising a plug of filter material, a tobacco core extending substantially longitudinally through the plug of filter material, and wrapping means wrapped around at least a portion of a longitudinally extending surface of the tobacco core.

2. The filter element according to claim 1, wherein the tobacco core extends substantially longitudinally between mutually opposing end faces of the plug of filter material.

3. The filter element according to claim 2, wherein the tobacco core extends in a direction which is substantially parallel to a side face of the plug of filter material, which side face is substantially perpendicular to one or both end faces.

4. The filter element according to claim 1, wherein the tobacco core extends through an inner portion of, and is surrounded by, the filter material.

5. The filter element according to claim 1, wherein the tobacco core extends through substantially the center of the plug of filter material.

6. The filter element according to claim 1, wherein the tobacco core comprises shredded tobacco, powdered tobacco, reconstituted tobacco, tobacco fibers, tobacco sheet, cut tobacco lamina, cut tobacco blend or tobacco stem.

7. The filter element according to claim 1, wherein the tobacco core is substantially cylindrical in shape.

8. The filter element according to claim 1, wherein the wrapping means is substantially permeable to air.

9. The filter element according to claim 1, wherein the wrapping means is formed of any conventional paper material.

10. The filter element according to claim 1, wherein the wrapping means is in contact with substantially all of the longitudinally extending side surface of the tobacco core.

11. The filter element according to claim 1, wherein the tobacco core comprises, or is derived from, at least a longitudinal section of a tobacco rod of the smoking article.

12. A filter element for a smoking article, the filter element comprising a plug of filter material, and a tobacco core extending substantially longitudinally through the plug of filter material, wherein the tobacco core comprises, or is derived from, a longitudinal section of a tobacco rod of the smoking article.

13. The filter element according to claim 12, wherein the tobacco core comprises, or is derived from, the longitudinal section of the tobacco rod of a slim-sized smoking article.

14. The filter element according to claim 12, wherein the tobacco core in the filter element is between 3 mm and 8 mm in diameter.

15. The filter element according to claim 12, wherein the filter material comprises cellulose acetate.

16. The filter element according to claim 12, wherein the diameter of the plug of filter material is between 5 and 15 mm.

17. A filter for the smoking article, the filter comprising the filter element according to claim 12.

18. The filter according to claim 17, wherein the filter comprises a plurality of filter elements, at least one of which is a filter element comprising a plug of filter material, a tobacco core extending substantially longitudinally through the plug of filter material, and wrapping means wrapped around at least a portion of a longitudinally extending surface of the tobacco core.

19. The filter according to claim 17, wherein the filter comprises an adsorbent filter element, which element comprises an adsorbent material.

20. The filter according to claim 19, wherein the adsorbent material is activated carbon.

21. The filter according to claim 17, wherein the filter comprises the filter element, which comprises filter material, and which does not include the tobacco core or adsorbent material.

22. A smoking article comprising a filter according to claim 17.

23. A method of manufacturing a filter element for a smoking article, the method comprising providing a tobacco core through a plug of filter material, wherein the tobacco core extends substantially longitudinally through the plug of filter material, and wherein wrapping means is wrapped around at least a portion of a longitudinally extending surface of the tobacco core.

24. A method of manufacturing a filter element for a smoking article, the method comprising providing a tobacco core through a plug of filter material, wherein the tobacco core extends substantially longitudinally through the plug of filter material, and wherein the tobacco core comprises, or is derived from, a longitudinal section of a tobacco rod of a smoking article.

25. The method according to claim 24, wherein the method comprises arranging the longitudinal section of the tobacco rod of a slim-sized smoking article, such that it extends substantially longitudinally through the plug of filter material.

26. The method according to claim 23, wherein the method comprises introducing the tobacco core into substantially the center of the filter material.

27. The filter element according to claim 1, wherein the tobacco core in the filter element is between 3 mm and 8 mm in diameter.

28. The filter element according to claim 1, wherein the tobacco core in the filter element is between 4 mm and 6 mm in diameter.

29. The filter element according to claim 1, wherein the filter material comprises cellulose acetate.

30. The filter element according to claim 1, wherein the diameter of the plug of filter material is between 5 mm and 15 mm.

31. The filter element according to claim 1, wherein the diameter of the plug of filter material is between 7 mm and 9 mm.

32. A filter for the smoking article, the filter comprising the filter element according to claim 1.

33. A smoking article comprising a filter element according to claim 1.

34. The filter element according to claim 12, wherein the tobacco core in the filter element is between 4 mm and 6 mm in diameter.

35. The filter element according to claim 12, wherein the diameter of the plug of filter material is between 7 mm and 9 mm.

36. The filter according to claim 17, wherein the filter comprises a plurality of filter elements, at least one of which is a filter element comprising a plug of filter material, and a tobacco core extending substantially longitudinally through the plug of filter material, wherein the tobacco core comprises, or is derived from, a longitudinal section of a tobacco rod of the smoking article.

37. The method according to claim 24, wherein the method comprises introducing the tobacco core into substantially the center of the filter material.