MXPA99007008A - Smoking articles - Google Patents

Abstract

The invention relates to a coaxial smoking article, particularly a coaxial cigarette, comprising a coaxial rod of smokable material, which rod has an inner segment (1) of smokable material surrounded by a covering (2), around which covering is an outer segment (3) of combustible or thermally destructible/decomposable material, which outer segment is also surrounded by a covering (4). The combustible or thermally destructible/decomposable material of the outer segment contains no or only a very small proportion of spot-forming substances. Further, the coverings of the inner and outer segments are such that spot-forming substances in the inner segment are essentially unable to reach the outside of the outer covering. Hence, a cigarette having a reduced potential for the production of spotting is so formed.

Description

SMOKING ARTICLES The present invention relates to articles for smoking and in particular to cigarettes having reduced stain formation and less sidestream smoke. If the cigarettes are stored for a long period of time, then staining may occur on the cigarette paper. This staining is caused by particular substances in the smokable material, which may comprise cut tobacco material, of the cigarette, whose substances for a long period of time can pass through the paper to the outer surface thereof so that they form stains or discolored regions on the cigarette paper. This produces a negative visual impression to the consumer. The smoke formed when a cigarette is smoked is commonly divided between mainstream smoke and sidestream smoke. The sidestream smoke is the smoke that does not pass through the filter into the mouth of the smoker and therefore is the smoke produced by the useless combustion of cut tobacco material. Thus, and also from the point of view of reducing the smoke passing to the surroundings, it is desirable to ensure that as small a fraction of sidestream smoke as possible is produced when a cigarette is smoked. An object of the present invention is to describe a cigarette which, on the one hand, is less likely to form spots on the paper thereof. An additional object is to produce a cigarette which, on the other hand, produces less sidestream smoke than conventional cigarettes when smoked. Either or both of these objects can be achieved by a cigarette with the features according to claim 1. The secondary claims relate to specific applications of the invention. This invention provides a cigarette formed as a coaxial cigarette with a tobacco coaxial rod, the inner segment of which contains a smokable material which is surrounded by a cover. Around the inner segment coverage there is an outer segment of combustible material or one that can be thermally decomposed / destroyed. This outer segment of combustible material that can be thermally decomposed is surrounded by additional coverage. The combustible material of the outer segment contains no or only a small fraction of stain-forming substances. The layers surrounding the inner segment of the coaxial braid, i.e., the internal coverage, the outer segment and the outer covering are constructed in such a way that the stain-forming substances which are present in the inner segment are in principle incapable of reaching the outer segment of the external coverage. This can be achieved, for example, by the internal segment surrounded by a covering having only very low permeability or which is impermeable to stain-forming substances.

Additionally, it is also possible that the inner and outer covers together with the outer segment form a type of barrier to stain-forming substances so that, for example, the substances passing through the internal cover are taken by the outer segment and it is prevented from passing through it. In this way, substances are prevented from reaching the external coverage. In addition, it is also possible that the external cover is such that it prevents the stain-forming substances that migrate through the internal cover and the outer segment from reaching the outer surface of the external cover, therefore no stains are formed in the same Particularly suitable materials for use with the outer segment are, for example, tobaccos having very low petroleum ether extractables. Suitable materials for the outer segment include clay materials, carbonates such as, for example, calcium carbonate, other mineral components or tobacco with a high fraction of mineral components. All these materials show no or only a very slight tendency to form spots and also ensure that only relatively few stain-forming substances can migrate from the inner segment to the outer covering. During the smoking of a cigarette, the smoke of a smokable material of the internal segment is mainly consumed by the smoker. This is due to the properties of the internal coverage, the outer segment and the external coverage, which are designed such that the smoke is maintained within the coaxial rod and therefore only a small amount of sidestream smoke can escape from the coaxial rod. The outer segment consists of combustible material or material that is thermally destructible so that the outer segment is degraded along with the inner segment during the smoking action, but only a relatively small amount or no particle phase components are produced from the material of the outer segment. Thus, the smoke actually consumed by the smoker is that which arises from the internal segment of the cigarette, while the components of the smoke of the combustible or thermally destructible material of the outer segment pass through the peripheral region of the cigarette. The fraction that has no value for the smoker also has no adverse effects on, for example, the taste of the cigarette and can be removed from the smoke stream by, for example, filters. The coaxial rod may be concentrically formed so that the internal and external segments are circular and have a common center point. Those skilled in the art will readily appreciate that it is also possible for one of the two segments to have an elliptical or rectangular shape. Of course, other forms are also possible. However, it is possible that the inner segment is completely surrounded by the coverage of the internal segment, the outer segment and the coverage of the outer segment so that due to these three layers, on the one hand, the substances Forms of internal segment staining can not reach the outer surface of the external covering and, on the other hand, it is ensured that when the coaxial cigarette is smoked, only relatively low quantities of the smoke produced by the material of the internal segment are lost as smoke from the internal segment. sidestream. Thus, the internal segment serves to provide smoke with an acceptable taste while the three layers arranged around the inner segment serve to reduce or prevent the formation of sidestream smoke and reduce or prevent the formation of spots. Conveniently, only the inner segment contains materials, particularly tobacco, treated with dry dung for fuel, including humectants, since these materials can produce a relatively high proportion of stain-forming substances. If the material of the outer segment does not contain dry dung for fuel, then the stain-forming substances in the inner segment are shielded from the outer surface of the outer covering by the three layers between them, that is, the three layers represent a barrier for stain-forming substances. Preferably, the coaxially disposed internal segment contains between 5 and 40% by weight of dry dung for fuel. If the internal segment contains, for example, 40% by weight of a dry dung for aroma-rich fuel then, due to this high proportion of dry dung for fuel in the segment internal, the smoke produced has a very intense taste when the coaxial cigarette is smoked. As, according to this invention, the material that reaches the smoker comes mainly from the inner segment of the coaxial cigarette, while the material in the outer segment contributes relatively nothing to the smoke, the coaxial cigarette, in comparison with a conventional cigarette of the same circumference produces the smoke to be consumed from a smaller segment of smokable material. This effect can be compensated for by the high proportion of dry dung for fuel and the intense flavors produced from it. Usually the components that are used as dry dung for fuel include, for example, sugars, cocoa, and licorice. The packing density of the smokable material in the inner segment is preferably in the range of 200 mg / cm3 to 320 mg / cm3, and more preferably in the range of 240 mg / cm3 to 280 mg / cm3. Packing density can be selected specifically according to tobacco, so that in the production a stable internal rod is formed. The pressure drop in the inner segment is preferably in the range of 100 mm WG to 200 mm WG, particularly in the range of 140 mm WG to 160 mm WG. Conveniently, the inner segment contains particularly aromatic tobaccos such as, for example, the so-called "Grades of Aroma", to at least 40% thereof. In this way, it can be assured that the smoke produced from the segment Internal when the inner segment is smoked offers a particularly full flavor sensation. The coverage of the inner segment may conveniently have a low to medium air permeability, preferably 0 to 60 Coresta Units. Preferably, the internal coverage does not allow the passage of stain-forming substances therethrough, so that the stain-forming substances in the inner segment can not reach the outer segment. The cigarettes according to the present invention have a common diameter of about 8 mm, the radial thickness of the outer segment is not greater than 1.5 mm, and preferably not greater than 1.0-0.5 mm, thus forming a thin barrier layer . This range is reached on the one hand from the need for an adequately thick barrier layer and the requirements of production conditions, and on the other hand for the desired proportions of materials not relevant for taste and relevant for flavor in the segments. It is particularly convenient that the materials of the outer segment when smoked under standard smoking conditions and in a conventional non-coaxial cigarette, have a high burning speed between puffs which is preferably in the range of 5 to about 15 mm per minute. As the outer segment is surrounded by external coverage that may have, for example, only a very low air permeability, or Being waterproof or substantially impervious to air, a high rate of combustion can ensure that the outer segment does not extinguish between puffs. The material in the outer segment may have combustion promoting substances, for example, combustion promoters such as potassium citrate, so that combustion in the outer segment does not cease between two sequential puffs. The packing density of the combustible material in the outer segment that does not have a considerable potential for the formation of the particle phase, is preferably in the range of about 80 to 180 mg / cm3 and more preferably in the range of 120 to 140 mg / cm3. By a low packing density of this type compared to the inner segment, potential sidestream smoke formation is reduced. Consequently, it is also convenient that the outer segment consists of combustible or thermally destructible materials or that they can be decomposed with a high filling value. This filling value can be in the range of approximately 4.7 to 15 cm3 / g. Preferably, the outer segment comprises mineral material, i.e., inorganic fillers, or sheet of expanded tobacco or tobacco stem or a mixture of these materials since, for example, expanded tobacco has, by definition, a filling value greater than tobacco not expanded.

The pressure drop in the outer segment is preferably in the range of 35 to 120 mm WG, and particularly in the range of 50 to 60 mm WG. In this way, it can be ensured that the flow velocity of the gas, i.e., smoke and / or air in the outer segment during the smoking action is relatively high due to the relatively small pressure drop. This produces an adequate combustion speed even when a cigarette paper is used with low air permeability in its construction. It is convenient to select the pressure drop in the inner segment and the outer segment so that there is a high gas flow velocity in the outer segment that produces the previously mentioned advantages. The ratio of the pressure drop in the inner segment to that of the outer segment is preferably greater than 1, since this contributes to an increase in the flow velocity in the outer segment relative to that of the internal segment. Preferably, the outer covering is formed such that there is a reduction in sidestream smoke, and the formation of spots is reduced. In accomplishing this, it is particularly useful if the outer coverage of the outer segment is either impermeable or has very low air permeability. It is especially convenient if this is below 1 5 Coresta units. This configuration of the external cover has the effect that the production of side stream smoke is further reduced.

The external cover may contain substances that promote combustion, so that in the case of an external cover having only low air permeability, the combustion promoting substances in the outer segment prevent the cigarette from extinguishing during the period between puffs. Coverage of the inner and outer segments of the coaxial rod of smokable material may consist of cigarette paper, reconstituted tobacco leaves or an inorganic shell such as disclosed in International Patent Application No. PCT / GB95 / 021 10. Also reference may be made to all means for reducing side stream smoke mentioned in German Patent No. 41 27 420 or in German Patent No. 39 01 226.

Additionally, the special properties of a filter applied to the tobacco rod of a coaxial cigarette as described in the two above mentioned patent specifications can also be used in coaxial cigarettes as described herein. The filter may consist of one or more coaxial segments placed, for example adjacent to the coaxial rod. Alternatively, a standard filter, i.e. a simple non-coaxial filter, can be used in conjunction with the smokable coaxial material rod. Additionally, a combination of a coaxial filter and a non-coaxial filter, i.e., a multiple filter or a chamber filter can of course be used.

If the filter comprises one or more coaxial segments, the coaxial segments preferably have an internal filter segment, an internal filter coverage that surrounds the internal filter segment, an external filter segment that surrounds the internal filter coverage and an internal filter coverage. External filter of the external filter segment. Conveniently, the internal filter coverage is impermeable or has very low air permeability. Preferably, the external filter cover has a ventilation zone, so that the filter can be ventilated. It is desirable that the pressure drop of the external filter segment and the internal filter segment be such that the ratio of the gas flow between the external filter segment and the internal filter segment is equal to or greater than the gas flow ratio from the outer segment to the inner segment of the coaxial rod of the smokable material. The filtration efficiency of the external filter segment is preferably greater than that of the internal filter segment, since smoke arising from the outer segment of the smokable rod should be removed mainly by filtration, while that of the internal coaxial segment should be delivered the smoker who has passed a lesser degree of filtration. Additionally, the external filter segment has a filtration efficiency greater than 80%, and is configured in such a way that the total or at least most of the smoke arising from the outer segment of the coaxial rod is removed by the coaxial filter. It is particularly important that the transverse areas of the inner and outer segments of the smokable coaxial rod correspond to the transverse areas of the inner and outer filter segments in size and shape. In order that the present can be easily understood and can be carried out, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 shows a coaxial cigarette of according to the invention with a bonded filter, and Figure 2 shows a cross-sectional view of a coaxial filter element. As can be seen from Figure 1, a coaxial cigarette 10 has a coaxial tobacco rod 1 1 and a filter 5. The tobacco rod 1 1 contains an internal indic cyl segment 1 which is surrounded by an internal or wrap-around 2 cover. Around the inner cover 2, there is an outer segment 3 having a circular cross section. The outer segment 3 is surrounded by the outer covering or envelope 4. The filter 5 is described with reference to Figure 2. Figure 2 shows an axial cross section of the coaxial filter 5 having an internal filter segment 6 which as the segment internal 1 of the coaxial tobacco rod 1 1 is cylindrical in shape and has the same cross section. The filter segment internal 6 is surrounded by an internal or enveloping cover 7, which is surrounded by an external filter segment 8. The external filter segment 8 is analogous in shape and dimension to the outer segment 3 of the coaxial tobacco rod 1 1 and has a cross-section in the form of ring or circular crown corresponding to the cross-section of the outer segment 3 of the coaxial tobacco rod 1 1. The external filter segment 8 is surrounded by an external or enveloping cover 9. The internal cover 2, the outer segment 3 and outer covering 4, form a "three-ply layer" ("triple layer") that on the one hand reduces secondary smoke and on the other hand prevents staining from forming on the outer surface of the external cover 4. For this purpose, the individual components of this coaxial cigarette 10 have the following properties. The cigarette 10 has the usual dimensions, a diameter of about 8 mm and a total length in the region 70 mm to about 100 mm. The total length is divided between the tobacco rod 1 1 and the filter 5 in the usual proportions. The outer covering 4 may comprise, for example, cigarette paper manufactured by Glatz Co. and marketed under the description G NS-40 MV which is practically impermeable to air and which contains a high proportion of combustion promoters eg potassium citrate. . The material d &i outer segment 3 comprises tobacco with a low potential patra ^ the formation of phase components of particles, with a proportion of mineral substances, particularly clay, and does not contain dry dung for fuel and / or flavor material. To this material are added combustion accelerators such as, for example, potassium citrate. The packing density of the fuel material in the outer segment 3 is approximately 1 30 mg / cm 3 and its filling capacities are approximately 8 cm 3 / g. The thickness of the outer segment in the form of an annular ring 3 is approximately 1 mm and its pressure drop is approximately 55 mm WG. The cover 2 of the inner segment 1 consists of a cigarette paper having an air impermeability of approximately 25 Coresta nities. A cigarette paper which produces less side stream smoke can also be selected. The internal segment 1 contains at least 40% by weight of aroma grade tobacco, all the materials of dry dung for fuel and all the humectants, of which, as an alternative, a small part can be put on the outer segment 3. Glycerin is the preferred humectant. Its percentage amount in the inner segment 1 is double that in the usual cigarettes if, for example, the weight of the inner segment 1 is approximately 50% of the total weight of the tobacco rod 1 1. In this way the humectant is used particularly efficiently since only a small part passes to the surroundings via Sidestream smoke. The construction of the filter 5 is adapted to the properties of the tobacco. If, for example, the material in outer segment 3 has a medium or low condensate potential and produces a smoke that is taste neutral, then a standard filter can be used. This includes all known coaxial filters, for example, multiple filters, carbon filters, camera filters and the like. In all other cases, a coaxial filter or a multiple filter with coaxial segments must be used. The pressure drop in the inner segment 6 and in the outer segment 8 provide a flow ratio in the filter that is approximately equal to or greater than the flow ratio of the inner segment 1 and the outer segment 3 of the coaxial tobacco rod 1 1 . The filter retention in the outer segment 8 is about 85%, while the filter retention in the inner segment 6 is less than 50%. The filter 5 has a ventilation zone 12, whose openings are indicated by the line interrupted in Figure 1 and which extend around the filter 5. The resulting degree of ventilation is approximately 60%.

Claims (1)

1. CLAIMS 1. A coaxial cigarette comprising a coaxial rod having: a) an internal segment (1) of smokable material; b) a coverage (2) for the internal segment (1); c) an outer segment (3) of thermally destructible or combustible material, whose outer segment surrounds the coverage (2) of the inner segment (2); and d) a cover (4) for the outer segment (3); wherein e) the combustible or thermally destructible material of the outer segment (3) contains no or only a very small proportion of stain-forming substances; and f) the internal coverage (2), the outer segment (3) and the external coverage (4) are formed so that the stain-forming substances in the internal segment (1) can not substantially reach the external coverage (4) 2 A cigarette according to claim 1, wherein only the inner segment (1) contains material, particularly tobacco treated with dry dung for fuel and / or humectants. 3. A cigarette according to any of the preceding claims, in which only the internal segment (1) contains 5% to 40% by dry dung for fuel of weight. 4. A cigarette in accordance with any of the previous claims, wherein the packing density of the smokable material in the inner segment (1) is from about 200 to 320 mg / cm3. 5. A cigarette according to claim 4, wherein the packing density of the smokable material in the inner segment (1) is from about 240 to 280 mg / cm3. 6. A cigarette according to any of the preceding claims, wherein the pressure drop in the inner segment (1) is in the range of about 100 mm WG to 200 mm WG. 7. A cigarette according to claim 6, wherein the pressure drop in the inner segment (1) is in the range of about 140 mm WG to 160 mm WG. 8. A cigarette according to any of the preceding claims, wherein the inner segment (1) contains at least 40% of particularly aromatic tobacco. 9. A cigarette according to any of the preceding claims, wherein the internal coverage (2) consists of cigarette paper or reconstituted tobacco sheet. 10. A cigarette according to claim 9, wherein the internal cover (2) has low to medium air permeability. eleven . A cigarette according to claims 9-1 0, in which the internal cover (2) has an air permeability of 0 to 60 Coresta Units. 12. A cigarette according to any of the preceding claims, wherein the internal cover (2) is essentially impermeable to stain-forming substances. 13. A cigarette according to any of the preceding claims, wherein the radial thickness of the outer segment (3) is a maximum of 1.5 mm. 14. A cigarette according to any of the preceding claims, wherein the fuel material in the outer segment (3) when smoking in a conventional non-coaxial cigarette under standard smoking conditions has a high rate of combustion between puffs particularly in the range of 5 to 15 mm / min. 15. A cigarette according to any of the preceding claims, wherein the combustible material of the outer segment (3) contains combustion promoting substances, particularly burn promoters. 16. A cigarette according to claim 14 in which the combustion promoter is potassium citrate. 17. A cigarette according to any of the preceding claims, wherein the packing density in the outer segment (3) is in the range of about 80 to 180 mg / cm3. 18. A cigarette according to claim 16, wherein the packing density of the outer segment (3) is in the range of about 120 to 140 mg / cm3. 19. A cigarette according to any of the preceding claims, wherein the fraction of materials in the outer segment (3) that does not have a considerable potential to form particulate phase constituents, has a high filling value. 20. A cigarette according to claim 18 wherein the fill value is in the range of about 4.7 to 15 cm3 / g. twenty-one . A cigarette according to any of the preceding claims, wherein the outer segment (3) contains mineral materials and / or expanded tobacco in the form of sheet and / or rod. 22. A cigarette according to claim 20, wherein the mineral materials include inorganic fillers. 23. A cigarette according to any of the preceding claims, wherein the pressure drop in the outer segment (3) is in the range of about 35 to 120 mm WG. 24. A cigarette according to claim 22, wherein the pressure drop in the outer segment (3) is in the range of about 50 to 60 mm WG. 25. A cigarette according to any of the preceding claims, wherein the pressure drop in the inner segment (1) and the outer segment (3) are selected such that there is a high gas flow velocity in the segment outside (3). 26. A cigarette according to any of the preceding claims, wherein the ratio of the pressure drop in the inner segment (1) to the pressure drop in the outer segment (3) is greater than 1. 27. A cigarette according to any one of the preceding claims, wherein the external cover (14) is formed in such a way as to reduce sidestream smoke. 28. A cigarette according to any of the preceding claims, wherein the outer covering (4) is designed in a manner that reduces stain formation. 29. A cigarette according to any of the preceding claims, wherein the outer covering (4) consists of a thick cigarette paper. 30. A cigarette according to any of the preceding claims, wherein the outer covering (4) has no or only a slight air permeability. 31 A cigarette according to claim 29, wherein the air permeability of the outer covering (4) is less than 15 Coresta Units. 32. A cigarette according to any of the preceding claims, wherein the external cover (4) contains combustion promoting substances. 33. A cigarette according to any of the preceding claims, wherein the cigarette has a filter (5). 34. A cigarette according to claim 32, wherein the filter (5) has at least one coaxial segment on the side facing the coaxial rod 10. 35. A cigarette according to any of claims 32 or 33, wherein the filter (5) has an internal filter segment (6), an internal filter cover (7) of the internal filter segment (6), an external filter segment (8) surrounding the filter cover internal (7) of the internal filter segment (6) and an external filter coverage (9) of the external filter segment (8). 36. A cigarette according to claim 34, wherein the internal filter cover (7) of the filter (5) is impermeable or has only very slight air permeability. 37. A cigarette according to any of claims 32 to 35, wherein the external filter cover (9) has a ventilation zone. 38. A cigarette according to any of claims 34 to 36, wherein the pressure drops in the external filter segment (8) and the internal filter segment (6) are selected such that the flow ratio of gas in the external filter segment (8) to the internal filter segment (6) is equal to or greater than the ratio of the gas flow in the outer segment (3) to the internal segment (1) of the coaxial rod (10). 39. A cigarette according to any of claims 34 to 37, in which the filtration efficiency of the external filter segment (8) is greater than the filtration efficiency of the internal filter segment (6). 40. A cigarette according to any of claims 34 to 38, wherein the efficiency of the external filter segment (8) is greater than 80%. 41. A cigarette according to any of the preceding claims, wherein the cross-sectional areas of the internal and external segments (1, 3) of the coaxial rod (10) correspond in size and shape to the transverse areas of the segments of internal and external coaxial filter (6, 8).