Filter with improved hardness and filtration efficiency

Abstract

There is provided a smoking article comprising an aerosol generating substrate and a mouthpiece attached to the aerosol generating substrate. The mouthpiece includes a segment comprising a filtration material comprising polylactic acid, and an additive for reducing phenols. The mouthpiece further comprises one or more wrappers circumscribing the segment, the one or more wrappers have a combined basis weight of at least about 50 grams per square metre (gm-.sup.2).

Claims

1. A smoking article comprising: an aerosol generating substrate; and a mouthpiece attached to the aerosol generating substrate, the mouthpiece comprising a segment comprising: a filtration material comprising polylactic acid; and an additive for reducing phenols; wherein the additive comprises a mixture of triacetin with cellulose acetate flakes.

2. A smoking article according to claim 1 wherein the filtration material comprises a plurality of fibres formed at least in part of polylactic acid.

3. A smoking article according to claim 2, wherein the fibres are substantially unconnected to one another.

4. A smoking article according to claim 3, wherein the filtration material comprises a blend of the polylactic acid and at least one other polymer.

5. A smoking article according to claim 1, wherein the filtration material comprises a blend of the polylactic acid and at least one other polymer.

6. A smoking article according to claim 5, wherein the blend comprises a blend of the polylactic acid, polyglycolic acid and poly-(L)-lactic acid.

7. A smoking article according to claim 1, wherein the additive for reducing phenols is dispersed amongst the filtration material.

8. A smoking article according to claim 7, wherein the additive for reducing phenols is the only additive provided in the segment.

9. A smoking article according to claim 1, wherein the additive for reducing phenols is the only additive provided in the segment.

10. A smoking article according to claim 1, wherein the mouthpiece further comprises one or more wrappers circumscribing the segment, and wherein the one or more wrappers have consists of a single wrapper having a base weight of at least 50 grams per square metre (gm.sup.2), or wherein the one or more wrappers consists of a plurality of wrappers, the plurality of wrappers having a combined basis weight of at least 50 grams per square metre (gm.sup.2).

11. A smoking article according to claim 10, wherein the one or more wrappers comprise a first wrapper, the first wrapper being in direct abutment with the filtration material and having a basis weight of at least 50 grams per square metre (gm.sup.2).

12. A smoking article according to claim 10, wherein the one or more wrappers consists of a single wrapper having a thickness of at least about 80 m, or wherein the one or more wrappers consists of a plurality of wrappers, the plurality of wrappers having a combined thickness of at least 80 m.

13. A smoking article according to claim 10, wherein the one or more wrappers consists of a single wrapper having a bending stiffness of at least 0.08 N in a machine direction of the wrapper, or wherein the one or more wrappers consists of a plurality of wrappers, the plurality of wrappers having a combined bending stiffness of at least 0.08 N in the machine direction of the plurality of wrappers.

14. A smoking article according to claim 1, wherein the segment has a hardness of at least about 75%.

15. A smoking article according to claim 1, wherein the segment has an ovality, after a 50% deformation of the segment, of less than about 25%.

16. A smoking article according to claim 1, wherein the filtration material comprises a gathered sheet of material comprising the polylactic acid.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 illustrates the definition of hardness;

(3) FIG. 2 illustrates the definition of ovality, using a perfect circle;

(4) FIG. 3 illustrates the definition of ovality, using an oval;

(5) FIG. 4 shows an unwrapped smoking article in accordance with a first embodiment of the present invention;

(6) FIG. 5 illustrates a perspective view of an apparatus for determining the hardness of a filter or a smoking article, in a first configuration;

(7) FIG. 6 illustrates a side view of the apparatus of FIG. 5, in a first configuration;

(8) FIG. 7 illustrates a side view of the apparatus of FIG. 5, in a second configuration;

(9) The filter cigarette 10 shown in FIG. 4 comprises a wrapped rod 12 of tobacco cut filler which is attached at one end to an axially aligned filter 14 in accordance with the present invention. The filter 14 comprises a single segment 16 of filtration material, the filtration material comprising fibres formed from a blend of about 85% by weight polylactic acid, 10% by weight polyglicolic acid, and 5% by weight poly-(L)-lactic acid. The segment 16 also comprises an additive for reducing phenols in the smoke produced by the tobacco rod 12. The segment of filtration material 16 is circumscribed by a plug wrap 18, having a basis weight of about 78 grams per square metre. The wrapped tobacco rod 12 and the filter 14 are joined by a band 20 of tipping paper, which circumscribes the entire length of the filter 14 and an adjacent portion of the wrapped tobacco rod 12.

(10) Six different sample filters were constructed with the filtration materials shown in Tables 1 and 2 below. The filters were attached to tobacco rods to form smoking articles and the smoking articles were subjected to a standard smoking test under ISO conditions (35 ml puffs lasting 2 seconds each, with puffs occurring once every 60 seconds) as set out in ISO 4387:2000. In the ISO test method, the smoking article is smoked with the ventilation zone fully uncovered. The delivery levels of certain phenols for each smoking article were measured. Tables 1 and 2 show the delivery levels of these smoke constituents per milligram of nicotine delivery, for each of the six different sample smoking articles.

(11) TABLE-US-00001 TABLE 1 Smoke PLA Fibres + 10% constituent Reference Polylactic PLA Mixture (of 96-98% normalized to Cellulose Acid (PLA) Fibres + triacetin + 2-4% milligram (mg) Acetate Fibres + Fibres + 10% cellulose acetate of nicotine 7% Triacetin No additive Triacetin flakes) Phenol (g) 10.87 27.20 14.92 11.82 m cresols (g) 2.43 4.53 2.94 2.54 p cresols (g) 6.04 11.68 7.32 6.44 o-cresol (g) 2.87 6.25 3.35 2.64

(12) TABLE-US-00002 TABLE 2 Smoke PLA constituent Reference Polylactic PLA Fibres + normalized to Cellulose Acid (PLA) Fibres + 10% milligram (mg) Acetate Fibres + Fibres + 10% Triethyl of nicotine 7% Triacetin No additive PEG400 Citrate Phenol (g) 10.87 27.20 10.28 6.90 m cresols (g) 2.43 4.53 2.48 1.72 p cresols (g) 6.04 11.68 6.29 4.36 o-cresol (g) 2.87 6.25 2.67 1.49

(13) As can be seen from Tables 1 and 2, the filter having polylactic acid (PLA) fibres with no additive delivered a noticeably higher amount of phenols than the reference standard cellulose acetate filter. However, the filters having polylactic acid with an additive delivered a comparable or lower amount of phenols than the reference standard cellulose acetate filter.

(14) FIGS. 5, 6 and 7 depict an apparatus for testing the hardness of smoking articles filters.

(15) The apparatus may be a known DD60A Densimeter (manufactured and made commercially available by Heinr. Borgwaldt GmbH, Germany) device, which is fitted with a measuring head for cigarettes and with a cigarette receptacle. As described in more detail below, the hardness of samples can be tested by following the method which is recommended for the known DD60A Densimeter device (manufactured and made commercially available by Heinr. Borgwaldt GmbH, Germany). That is, a sample of smoking articles is held in parallel alignment, and subjected to an overall load of 2 kg, for a period of 20 seconds, and the diameters of the smoking articles before and after compression are recorded. The depression is used to determine the hardness (%) of each smoking article.

(16) FIG. 5 is a perspective view of an apparatus 4, such as a DD60A Densimeter device, for determining the hardness of a filter of a smoking article. The apparatus includes two parallel load applying rods 24 positioned over a support plate 30. The support plate 30 includes two parallel, spaced apart walls 12, with each wall 12 having ten equally spaced recesses. The recesses are arranged to prevent the smoking articles 10 from contacting one another during testing.

(17) As can be seen in FIG. 5, ten identically designed smoking articles 10 are aligned parallel in a plane, and placed on underlying cylindrical rods 14. The smoking articles 10 extend between corresponding recesses in the walls 12 to hold the smoking articles in place. The underlying cylindrical rods 14 extend parallel to the walls 12. Each smoking article 10 contacts the underlying rods 14 at two points, making for twenty total points of contact between the smoking articles to be tested and the underlying rods 14.

(18) To test the hardness of a smoking article's filter, the smoking articles should be positioned such that the portion of the filter to be tested is in contact with the underlying rods 14. If filter is too short and the portion of the filter to be tested either does not contact both rods or contacts the rods very close to the ends of the portion of the filter to be tested, then it would be appreciated that this could be achieved by using twenty cigarettes in a back-to-back configuration, such as that shown in FIG. 6.

(19) As shown, the concept of the DD60A Test is that the underlying cylindrical rods contact the sample material to be tested at twenty contact points. If the filter is sufficiently long to extend across the underlying rods, then the twenty contact points can be provided with ten samples (as shown in FIG. 5). If the filter is not sufficiently long, then the twenty contact points can be provided with twenty samples, as shown in FIG. 6.

(20) As can be seen in FIG. 6, portions of the tobacco rods have been removed from each smoking article 10, and the filter portion of each smoking article 10 rests on a respective cylindrical rod 14. In FIG. 6, the hardness of the mouth end segment is being tested, and therefore it is this portion of the filter which rests on the rod 14, and the mouth end segment is approximately centered on the rods 14. If necessary, the tips of the smoking articles extending away from the cylindrical rods 14 may be supported by an underlying supporting means to prevent pivoting of the smoking articles.

(21) The apparatus is shown in FIG. 6 in a first configuration, in which the two load applying cylindrical rods 24 are raised above and out of contact from the smoking articles 10. To test the hardness of the smoking articles, the load applying cylindrical rods 24 are lowered to a second configuration, to come into contact with the smoking articles 10, as shown in FIG. 7. When in contact with the smoking articles 10, the load applying rods 24 impart an overall load of 2 kg across the twenty contact points of the smoking articles 10 for a duration of 20 seconds. After 20 seconds have elapsed (and with the load still being applied to the smoking articles), the depression in the load applying cylindrical rods 24 across the smoking articles is determined, and then used to calculate the hardness.