Radially rigid smoking article filters

Abstract

To provide a smoking article which comprises a radially firm smoking article filter tobacco rod, a filter, and a tipping material attaching the tobacco rod and the filter.SOLUTION: The filter comprises a plug of filtration material that defines a downstream end segment of the smoking article, the plug being surrounded by one or more filter wrappers. The hardness of the smoking article at the downstream end segment is at least about 90%, and the filtration material extends to the furthest downstream end of the filter.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to filters for smoking articles and smoking articles equipped with filters.

[0002] Combustible smoking articles, such as cigarettes, typically comprise shredded tobacco (usually in the form of cut filler) surrounded by a paper wrapper that forms a tobacco rod. A cigarette is consumed by a consumer by lighting one end of the cigarette and burning the shredded tobacco rod. The consumer then receives mainstream smoke by drawing on the opposite end (the mouth end or filter end) of the cigarette. The shredded tobacco may be a single type of tobacco or a mixture of two or more types of tobacco.

[0003] Smoking articles, particularly cigarettes, commonly include a filter aligned in end-to-end relationship with a tobacco rod or other aerosol-forming substrate. Typically, the filter includes a plug of cellulose acetate tow adhered to the tobacco rod or substrate by tipping paper that covers the filter and adjacent portions of the tobacco rod. Mainstream smoke ventilation can be achieved by one or more rows of perforations in the tipping paper located near positions along the filter.

[0004] Some consumers in certain markets, such as Korea, enjoy biting the mouth end of the filter while smoking a smoking article. Consumers generally desire the filter to provide some resistance during the biting action. However, biting can deform the filter shape, thereby affecting the smoking experience. Consumers may also perceive filters that are not particularly stiff as being of lower quality.

[0005] It would therefore be desirable to provide a filter for a smoking article that provides the consumer with an improved sensory experience, such as an improved chewing experience.

[0006] According to a first aspect of the present invention, there is provided a smoking article comprising: a tobacco rod; a filter including a plug of filtration material defining a downstream end segment of the smoking article, the plug being surrounded by one or more filter wrappers; and a tipping material adhering the tobacco rod and the filter; wherein the hardness of the smoking article at the downstream end segment is at least about 90%, the filtration material extends to the furthest downstream end of the filter, and the one or more filter wrappers have a basis weight of between about 50 grams per square meter and about 100 grams per square meter.

[0007] The inventors of the present invention have found that the mouth end of a smoking article filter must have a hardness of at least about 90% so that consumers can enjoy biting the mouth end during a smoking experience. This provides sufficient resistance to the consumer to make the chewing experience more enjoyable. If the hardness is less than about 90%, the mouth end is perceived as too flexible and soft by consumers. In addition, the filtering material of the filter plug extends to the farthest downstream end of the smoking article, the mouth end. That is, the mouth end of the filter is filled and does not form a cavity or hollow mouth end. This can provide additional resistance to the consumer, which can further improve the chewing experience. In contrast to a hollow mouth end, the mouth end of the filter will not collapse when bitten.

[0008] By providing a filter with at least 90% stiffness at the mouth end and by providing filtration material that extends to the mouth end, the overall sensory experience for the consumer can be improved because the mouth end of the filter provides sufficient resistance to deformation due to chewing that is enjoyable to the consumer, and the overall quality can be perceived as higher.

[0009] As used herein, the terms "upstream" and "downstream" are used to describe the relative positions of elements of a filter or smoking article relative to the direction of mainstream smoke as it is drawn through the filter and out the lighting end of the smoking article. Mainstream smoke flows longitudinally, generally parallel to the length of the smoking article. The transverse direction of the smoking article is perpendicular to the longitudinal axis.

[0010] The term "stiffness" as used throughout this specification means resistance to deformation. Stiffness is commonly expressed as a percentage. Figure 1 shows a cigarette 101 before the application of a load F and the same cigarette 103 while the load F is applied. Before the load F is applied, the cigarette 101 has a diameter D S After applying the set load for the set period (but still under load), the cigarette 103 has a (reduced) diameter D d The depression is d = D S -D d is. Referring to Figure 1, the hardness is: JPEG0007799765000001.jpg14160, where D S is the original (undepressed) cigarette diameter, and D d is the depressed diameter after a set load is applied for a set period of time. The harder the material, the closer the stiffness is to 100%.

[0011] As described in more detail below and as is generally known in the art, to determine the hardness of a portion of a smoking article (such as a filter), the smoking article should be aligned parallel to a plane, and the same portion of each smoking article being tested should be subjected to a set load for a set period of time. This test is performed using a known DD60A Densimeter instrument (manufactured and sold by Heinr. Borgwaldt GmbH, Germany), which is fitted with a measuring head for cigarettes and a cigarette receptacle.

[0012] The load is applied using two cylindrical load rods, which extend across the entire diameter of the smoking article at one time. According to the standard test method for this device, the test should be conducted to create 20 contact points between the smoking article and the load utilizing the cylindrical rods. In some cases, the filter being tested may be long enough that only 10 smoking articles are needed to create 20 contact points (because they are long enough to extend between the rods), with each smoking article contacting both load rods. In other cases, if the filter is too short to achieve this, 20 smoking articles should be used to create 20 contact points, with each smoking article contacting only one of the load rods, as described further below.

[0013] Two additional fixed cylindrical rods are positioned below the smoking article to support the smoking article and counter the loads exerted by each of the loading cylindrical rods, such an arrangement is described in more detail below and shown in Figures 4-6.

[0014] The standard operating procedure for such a device is to apply the entire 2 kg load for 20 seconds. After 20 seconds have elapsed (and the load is still applied to the smoking article), the depression on the cylindrical rod applying the load is determined and then used to calculate the hardness from the above equation. The temperature is maintained in the range of 22 degrees Celsius ± 2 degrees Celsius. The above test is referred to as the DD60A test. The DD60A test and the corresponding device are detailed below in Figures 4-6. As detailed below, the hardness of the filter portion of a smoking article is not significantly different when the smoking article is smoked rather than unsmoked. However, the standard method for measuring filter hardness is when the smoking article is unsmoked.

[0015] In accordance with the present invention, the hardness of the smoking article at the downstream end (mouth end) segment is at least about 90%. More preferably, the hardness of the smoking article at the downstream end segment is at least about 92%. This provides even greater resistance to the consumer, for example, when chewing.

[0016] It may be advantageous for the rigidity of a smoking article according to the present invention to be provided primarily by one or more filter wrappers rather than by the tipping material. This would obviate the need for particularly thick tipping materials. This may allow the ventilation zone to be formed directly in the tipping material. This may also allow the tipping material to be easily curved around the smoking article during manufacture to adhere the tobacco rod and filter.

[0017] Thus, the filter wrapper or wrappers may be approximately 50 grams per square meter (gm -2 ), which has been found to provide the desired stiffness while limiting the ovality achieved after deformation. The filter wrapper or wrappers have a basis weight of greater than about 100 gm -2 It should be noted that such a value can provide an excellent balance between stiffness and ovality, while still allowing the filter wrapper to be relatively straight for handling during manufacturing.

[0018] Preferably, the one or more filter wrappers are about 65 gm -2 ~about 85 gm -2 Even more preferably, the filter wrapper or wrappers have a basis weight of between about 70 gm -2 ~about 80 gm -2 In preferred embodiments, a single filter wrapper is provided, and the single filter wrapper has a basis weight as set forth above. Alternatively, in some embodiments, multiple filter wrappers may be provided, and the combined basis weight of the multiple wrappers may be as set forth above.

[0019] Some (limited) flexibility when chewed by a consumer is preferred so that the consumer can enjoy biting the mouth end of the smoking article filter. Thus, preferably, the hardness of the smoking article at the downstream terminal segment is about 94% or less.

[0020] The present inventors have also found that it is preferable for the mouth end to return to as close to a circle as possible after chewing so that the consumer can continue to enjoy the smoking experience after chewing the mouth end, i.e., the mouth end preferably has low ovality after deformation (e.g., after chewing).

[0021] The term "ovality" as used throughout this specification refers to the degree of deviation from a perfect circle. Ovality is commonly expressed as a percentage. Figure 2 shows a perfect circle. In Figure 2, both diameters are equivalent to the diameter of the circle, so diameter a = diameter b. Figure 3 shows an ellipse. In Figure 3, diameter a ≠ diameter b. With reference to Figures 2 and 3, ovality is: JPEG0007799765000002.jpg14162, where a is the largest outer diameter of the ellipse or circle, and b is the smallest outer diameter of the ellipse or circle. In the case of an ellipse or ellipse, a is the major axis of the ellipse, and b is the minor axis of the ellipse. Since a = b for a perfect circle, the ellipticity of a perfect circle is equivalent to 0%.

[0022] To determine the ovality of a portion of a smoking article (such as a filter) according to the present invention, the mouth end is viewed along the length of the smoking article. For example, the smoking article may be placed at its mouth end on a transparent stand, so that an image of the mouth end of the smoking article is recorded by a suitable imaging device located below the stand. The process is repeated for a total of 10 smoking articles having the same design, and the average of the 10 ovality measurements is recorded as the ovality for that particular design of smoking article.

[0023] To simulate smoking of a smoking article, the smoking article is subjected to a standard smoking test under ISO conditions (35 ml puffs lasting 2 seconds each, with one puff occurring every 60 seconds), as described in ISO 4387:2000. In the ISO test method, the smoking article is smoked with the ventilation zone fully open. If it is necessary to measure the ovality after deformation tests conducted both before and after smoking, two samples of smoking articles with the same design should be used. That is, an undistorted, undistorted smoking article should be used for the deformation test before smoking, and an undistorted smoking article with the same design should be subjected to the smoking test and used for the deformation test after smoking.

[0024] It is preferable that the mouth end has low ovality after deformation. It has also been found that smoking article filters with softer filter wrappers tend to have low ovality after deformation. However, such filter wrappers may be too soft for consumers to enjoy a chewing experience. Therefore, preferably, the ovality of the farthest downstream end of the smoking article is less than about 25% after 50% deformation of the farthest downstream end of the smoking article. This means that, combined with a minimum hardness of at least about 90%, the mouth end of the smoking article has a maximum ovality of about 25% after 50% deformation. This allows the smoking experience to be enjoyed after chewing, and also provides a mouth end that is sufficiently hard so that the chewing experience itself can be enjoyed.

[0025] Moreover, it is preferred that the mouth end return to as close to a circle as possible after chewing, even after smoking. Thus, preferably, the ovality of the smoking article's farthest downstream end is less than about 25% after a 50% deformation of the smoking article's farthest downstream end, performed after the smoking article has been subjected to a smoking test (as described above).

[0026] Preferably, the tipping material includes a ventilation zone located around the filter. The ventilation zone may include perforations through the tipping material. The amount of ventilation, including the number, layout, location, and size of the perforations, may be selected to provide a desired level of ventilation before and after chewing.

[0027] Preferably, the perforations extend through the filter wrapper surrounding the plug of filtration material. Alternatively, the filter wrapper may be porous. The tipping material may be a standard pre-perforated tipping material. Alternatively, the tipping material may be perforated (e.g., using a laser) during the manufacturing process according to the desired number, size, and location of perforations.

[0028] The one or more filter wrappers may comprise any suitable material or combination of materials. Examples of suitable materials include, but are not limited to, cellulose-based materials, paper, cardboard, recon, cellulose-based films, and combinations thereof. The one or more filter wrappers may be printed, embossed, embossed, or otherwise decorated with manufacturer or brand logos, trademarks, slogans, and other consumer information and indicia. Preferably, however, the one or more filter wrappers comprise paper.

[0029] Preferably, the filter wrapper(s) have low porosity. Preferably, the filter wrapper(s) have a porosity of less than about 1000 Coresta units, more preferably less than about 500 Coresta units, and even more preferably less than about 100 Coresta units. The porosity may be 100 Coresta units or less, or 20 Coresta units or less. Additionally or alternatively, the porosity may be greater than about 1 Coresta unit. Such low-porosity filter wrappers can help improve the strength of the filter and increase the critical load of the smoking article. This can be particularly beneficial when the filter includes perforations extending through the tipping paper and the filter wrapper(s).

[0030] As previously discussed, it may be beneficial for the stiffness of a smoking article according to the present invention to be primarily provided by one or more filter wrappers rather than by a tipping material. Accordingly, preferably, the one or more filter wrappers have a bending stiffness of at least about 0.08 N in the longitudinal direction of the filter wrapper. The one or more filter wrappers may have a bending stiffness of less than about 0.2 N in the longitudinal direction of the filter wrapper. The longitudinal direction of the filter wrapper preferably corresponds to the transverse direction of the smoking article.

[0031] Preferably, the one or more filter wrappers have a bending stiffness in the transverse direction of the filter wrapper of at least about 0.04 N. The one or more filter wrappers may have a bending stiffness in the transverse direction of the filter wrapper of less than about 0.1 N. The transverse direction of the filter wrapper preferably corresponds to the longitudinal direction of the smoking article.

[0032] As used herein, the term "flexural rigidity" refers to the resistance of a material to a bending force applied perpendicular to the plane of the material. Flexural rigidity may be determined by International Organization for Standardization (ISO) test ISO 5628:2012.

[0033] When more than one filter wrapper is provided, the total bending stiffness in a given direction of the one or more filter wrappers is the combined bending stiffness of each of the filter wrappers.

[0034] The diameter of the smoking article (the total diameter of the plug of filtration material together with the tipping material and filter wrapper, measured in a direction substantially perpendicular to the longitudinal axis of the smoking article) may have any suitable value, but it may be convenient for it to be substantially the same as a conventional smoking article.

[0035] Any suitable smoking article diameter may be selected, but preferably the diameter is between about 7.0 mm and about 8.0 mm, more preferably about 7.8 mm, and even more preferably 7.84 mm. The diameter may be about 7.0 mm.

[0036] The length of the filter (the total length of the filter, including the plug of filtration material, measured in a direction substantially parallel to the longitudinal axis of the smoking article) may have any suitable value. However, it may be convenient for the length of the filter to be substantially the same as that of a conventional smoking article. The length refers to the total length of the filter, including the plug of filtration material. That is, if the filter includes one or more filter segments in addition to the plug of filtration material, the length is the total length of all filter segments and the plug of filtration material. If the filter includes only the plug of filtration material, the length is the length of only the plug of filtration material.

[0037] Preferably, the filter has a length between about 15 mm and about 40 mm. Even more preferably, the filter has a length between about 18 mm and about 27 mm. In one embodiment, the filter has a length of about 27 mm. In another embodiment, the filter has a length of about 21 mm.

[0038] The filtration material may comprise any suitable material or combination of materials. The type of filtration material may be selected to provide the desired level of RTD during smoking and the desired level of firmness and ellipticity after deformation. Examples of suitable materials include, but are not limited to, thermoplastic materials such as cellulose acetate, cellulose, regenerated cellulose, polylactic acid, polyvinyl alcohol, nylon, polyhydroxybutyrate, starch, nonwoven materials, longitudinally oriented fibers and randomly oriented fibers, paper, crepe, PLA fibers, and combinations thereof. One or more materials may be formed into an open cellular structure. All or portions of the filter may contain activated carbon or other sorbents. The filter may contain adhesives or plasticizers, or combinations thereof. The filtration material may be compressible. In a preferred embodiment, the filtration material comprises cellulose acetate.

[0039] The filtration material may have any suitable denier per filament (dpf) and total denier (td). Preferably, however, the filtration material has a denier per filament (dpf) between about 5.0 dpf and about 12.0 dpf, more preferably between about 6.0 dpf and about 10.0 dpf. Preferably, the filter segments have a total denier of less than about 30,000, more preferably less than about 25,000. Additionally, or alternatively, the filter segments have a total denier greater than about 10,000. In one desirable embodiment, the filter segments comprise large diameter fibers having a total denier of about 15,000. The number of fibers present in the filter segment (total denier / dpf) can be less than about 6,000, but is preferably less than about 5,000. In one preferred embodiment, the filter material of the filter segments comprises fibers having a denier per filament of between about 5.0 and about 12.0 and a total denier of between about 12,000 and about 30,000.

[0040] Preferably, the filter contains a flavorant. The flavorant should be suitable to interact with and modify the characteristics of the smoking article and, therefore, the smoke derived therefrom. For example, the flavorant may impart flavor to enhance the taste of mainstream smoke produced during smoking.

[0041] The flavoring agent may be provided directly on a component of the filter. Alternatively, the flavoring agent may be provided as part of a flavoring agent delivery member configured to release the flavoring agent in response to a triggering mechanism. Such a triggering mechanism may include the application of a force to the filter, a change in temperature at the filter, a chemical reaction, or any combination thereof.

[0042] When the flavorant is provided as part of the flavorant delivery member, the flavorant delivery member may have any suitable structure in which a structural material removably encapsulates the flavorant or flavorants. For example, in some preferred embodiments, the flavorant delivery member comprises a matrix structure defining multiple domains, and the flavorant is trapped within the domains until released, for example, when an external force is applied to the smoking article. Alternatively, the flavorant delivery member may comprise a capsule. Preferably, the capsule comprises an outer shell and an inner core containing the flavorant. Preferably, the outer shell is sealed before the external force is applied, but is frangible or breakable to allow the flavorant to be released when the external force is applied. Capsules may be formed in a variety of physical configurations, including, but not limited to, single-part capsules, multi-part capsules, single-wall capsules, multi-wall capsules, large capsules, and small capsules.

[0043] When the flavorant delivery member includes a matrix structure defining multiple domains that encapsulate the flavorant, the flavorant delivery member may gradually release the flavorant when an external force is applied to the smoking article. Alternatively, when the flavorant delivery member is a capsule that is configured to burst or burst to release the flavorant when an external force is applied to the smoking article (for example, but not limited to, when the capsule includes an outer shell and an inner core), the capsule may have any desired burst strength. The burst strength is the force (acted on the capsule from outside the smoking article) at which the capsule bursts. The burst strength may be the peak in the capsule's force versus compression curve.

[0044] Suitable flavoring agents include, but are not limited to, natural or synthetic menthol, peppermint, spearmint, coffee, tea, spices (such as cinnamon, clove, and ginger), cocoa, vanilla, fruit flavors, chocolate, eucalyptus, geranium, eugenol, agave, juniper, anethole, and linalool-containing materials.

[0045] The tipping material may comprise any suitable material or combination of materials. Examples of suitable materials include, but are not limited to, cellulose-based materials, paper, cardboard, recon, cellulose-based films, and combinations thereof. The tipping material may be printed, embossed, embossed, or otherwise decorated with manufacturer or brand logos, trademarks, slogans, and other consumer information and indicia. Preferably, however, the tipping material comprises paper. The thickness of the tipping material is preferably between about 30 μm and about 70 μm, more preferably about 40 μm.

[0046] Preferably, the filter comprises a filtration material extending along the entire length of the filter. Preferably, it is in the form of a single segment filter. That is, preferably, the only filter segment in the filter is a plug of filtration material. Preferably, no further filter segments are provided either upstream or downstream of the plug of filtration material.

[0047] Alternatively, the filter may include one or more additional filter elements upstream of the plug of filtration material, so long as the filtration material of the filter plug extends to the mouth end of the smoking article. Thus, exemplary filter configurations that may be used include, but are not limited to, mono-filters, dual filters, triple filters, single or multi-cavity filters, and combinations thereof.

[0048] Where the filter comprises a multi-component filter comprising multiple filter segments, one or more filter wrappers may surround one, some or all of the filter segments. Preferably, each filter segment includes a respective filter wrapper, and the entire filter is surrounded by further filter wrappers.

[0049] If the filter comprises a multi-component filter including multiple filter segments, the tipping material may surround all of the filter segments in addition to the adjacent portions of the tobacco rod, or the tipping material may surround only a portion of the filter in addition to the adjacent portions of the tobacco rod.

[0050] The filter may be provided with any suitable resistance to draw (RTD). Preferably, the filter provides an RTD of between about 130 mm H2O and about 210 mm H2O.

[0051] The tobacco rod may include any suitable type or types of tobacco material or tobacco substitute in any suitable form.

[0052] Preferably, the tobacco rod comprises flue-cured tobacco, burley tobacco, Maryland tobacco, oriental tobacco, rare tobacco, specialty tobacco, or any combination thereof. Preferably, the tobacco is provided in the form of tobacco lamina, processed tobacco material such as volume-expanded or puffed tobacco, processed tobacco stems such as cut-rolled or cut-puffed stems, reconstituted tobacco material, mixtures thereof, and the like.

[0053] In some preferred embodiments, the tobacco is in the form of cut filler, i.e., in pieces or strings cut to widths ranging from about 2.5 mm to about 1.2 mm or just about 0.6 mm. Preferably, the strings have lengths ranging between about 6 mm and about 75 mm.

[0054] Preferably, the tobacco rod has at least about 200 mg / cm -3 More preferably, the tobacco rod has a tobacco packing density of at least about 220 mg / cm -3 More preferably, the tobacco rod has a tobacco packing density of at least about 240 mg / cm -3 The cigarette packing density is

[0055] According to a second aspect of the present invention, there is provided a filter for a smoking article, the filter comprising: a plug of filtration material defining a downstream end segment of the filter; one or more filter wrappers surrounding the plug of filtration material; wherein the stiffness of the filter at the downstream end segment is at least about 90%, and the filtration material extends to the furthest downstream end of the filter, and the one or more filter wrappers have a basis weight of between about 50 grams per square meter and about 100 grams per square meter.

[0056] By providing a filter that has at least 90% stiffness at the mouth end and by providing filtration material that extends to the mouth end, the sensory experience for the consumer can be improved, for example, because the mouth end of the filter provides sufficient resistance to deformation so that chewing and the like is enjoyable for the consumer.

[0057] Preferably, the stiffness of the filter at the downstream end segment is at least about 92%. Preferably, the stiffness of the filter at the downstream end segment is no more than about 94%.

[0058] The inventors of the present invention have also found that it is preferable for the mouth end to return to as close to a circle as possible after biting, so that the consumer can continue to enjoy the smoking experience after biting the mouth end. That is, the mouth end preferably has low ellipticity after biting (i.e., deformation). Thus, preferably, the ellipticity of the filter's farthest downstream end is less than 25% after 50% deformation of the filter's farthest downstream end.

[0059] As discussed in relation to the first aspect of the present invention, the filter wrapper or wrappers may comprise any suitable material or combination of materials.

[0060] Preferably, the filter wrapper or wrappers have a mass of about 50 grams per square meter (gm -2 ) Preferably, the filter wrapper or wrappers have a basis weight of greater than about 100 gm -2 More preferably, the filter wrapper or wrappers have a basis weight of less than about 65 gm -2 ~about 85gm -2 Even more preferably, the filter wrapper or wrappers have a basis weight of between about 70 gm -2 ~about 80gm -2In preferred embodiments, a single filter wrapper is provided, and the single filter wrapper has a basis weight as set forth above. Alternatively, in some embodiments, multiple filter wrappers may be provided, and the combined basis weight of the multiple wrappers may be a basis weight as set forth above.

[0061] In preferred embodiments, the one or more filter wrappers have a bending stiffness in the longitudinal direction of the filter wrapper of at least about 0.08 N. The one or more filter wrappers may have a bending stiffness in the longitudinal direction of the filter wrapper of less than about 0.2 N. The longitudinal direction of the filter wrapper preferably corresponds to the transverse direction of the smoking article.

[0062] In preferred embodiments, the one or more filter wrappers have a bending stiffness in the transverse direction of the filter wrapper of at least about 0.04 N. The one or more filter wrappers may have a bending stiffness in the transverse direction of the filter wrapper of less than about 0.1 N. The transverse direction of the filter wrapper preferably corresponds to the longitudinal direction of the smoking article.

[0063] As previously discussed with respect to the first aspect of the present invention, the total bending stiffness in a given direction of one or more filter wrappers is the combined bending stiffness of each of the filter wrappers.

[0064] The diameter of the filter (the diameter of the plug of filtration material together with the filter wrapper, measured in a direction substantially perpendicular to the longitudinal axis of the filter) may have any suitable value, but it may be convenient for the filter diameter to be substantially the same as that of a conventional smoking article.

[0065] As discussed with respect to the first aspect of the present invention, the filtration material may comprise any suitable material or combination of materials. The filtration material may have any suitable denier per filament (dpf) and total denier (td), such as any of the ranges mentioned above.

[0066] Preferably, the filter comprises a filtration material extending along the entire length of the filter. Preferably, it is in the form of a single segment filter. That is, preferably, the only filter segment in the filter is a plug of filtration material. Preferably, no further filter segments are provided either upstream or downstream of the plug of filtration material.

[0067] Alternatively, the filter may include one or more additional filter elements upstream of the plug of filtration material, so long as the filtration material of the filter plug extends to the mouth end of the filter.

[0068] Filters according to the present invention may be advantageously used in filter cigarettes and other smoking articles in which tobacco material is combusted to form smoke.

[0069] According to a third aspect, the present invention relates to the use of, or a method of using, a filter in a smoking article, the filter comprising: a plug of filtration material defining a downstream end segment of the smoking article; one or more filter wrappers surrounding the plug of filtration material, wherein the stiffness of the filter at the downstream end segment is at least about 90%, and the filtration material extends to the furthest downstream end of the filter, and the one or more filter wrappers are directed to a filter having a basis weight of between about 50 grams per square meter and about 100 grams per square meter.

[0070] Also, features and advantages described with respect to one embodiment of the invention may be applied to another embodiment of the invention.

[0071] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0072] [Figure 1] Illustrate the definition of hardness.

[0073] [Figure 2] A perfect circle is used to illustrate the definition of ellipticity.

[0074] [Figure 3] An ellipse is used to illustrate the definition of ellipticity.

[0075] [Figure 4] 1 illustrates a perspective view of an apparatus for determining the hardness of a filter or smoking article in a first configuration;

[0076] [Figure 5] 5 illustrates an embodiment of the device of FIG. 4 in a first configuration.

[0077] [Figure 6] 5 illustrates an embodiment of the device of FIG. 4 in a second configuration.

[0078] [Figure 7] 1 is a graph showing the stiffness (%) for six types of filters (in smoking articles) (both drawn and undrawn).

[0079] [Figure 8] 1 is a graph showing the stiffness (%) for six types of filters (not within smoking articles).

[0080] [Figure 9] 1 is a graph showing ovality (%) for three types of unbreathed filters.

[0081] [Figure 10] 1 is a graph showing the ovality (%) for three types of filters sucked.

[0082] As noted above, the inventors of the present invention have noted that the mouth end of the smoking article filter should have a hardness of at least about 90% so that a consumer can enjoy biting the mouth end during a smoking experience.

[0083] The hardness of various types of smoking articles was tested using a known DD60A Densimeter (manufactured and sold by Heinr. Borgwaldt GmbH, Germany) instrument, which was fitted with a measuring head and cigarette receptacle for cigarettes as described above. Samples were tested according to the following method recommended for the known DD60A Densimeter (manufactured and sold by Heinr. Borgwaldt GmbH, Germany): the smoking article samples were held in a parallel arrangement and subjected to a total load of 2 kg for 20 seconds, and the diameters of the smoking articles before and after compression were recorded. The compression was used to determine the hardness (%) of each smoking article.

[0084] The apparatus for testing the stiffness of smoking article filters is shown in FIGS. 4, 5 and 6, and the measured stiffness values ​​are shown in FIGS.

[0085] 4 is a perspective view of an apparatus 4 for determining the hardness of filters in smoking articles, such as a DD60A Densimeter apparatus. The apparatus includes two parallel load-applying rods 24 positioned on a support plate 30. The support plate 30 includes two parallel, spaced walls 12, each having ten equally spaced recesses. The recesses are positioned to prevent the smoking articles 10 from contacting each other during testing.

[0086] As can be seen in Figure 4, ten similarly designed smoking articles 10 are aligned parallel to a plane and placed on an underlying cylindrical rod 14. The smoking articles 10 extend between corresponding recesses in the wall 12 to hold the smoking articles in place. The underlying cylindrical rod 14 extends parallel to the wall 12. Each smoking article 10 contacts the underlying rod 14 at two points, making a total of 20 points of contact between the smoking article being tested and the underlying rod 14.

[0087] To test the filter hardness of a smoking article, the smoking article should be positioned so that the portion of the filter to be tested contacts the underlying rod 14. It will be appreciated that if the filter is too short and the portion of the filter to be tested does not contact both rods, or contacts a rod very close to the end of the portion of the filter to be tested, this can be achieved by using 20 cigarettes in a back-to-back arrangement, such as that shown in FIG.

[0088] As shown, the concept of the DD60A test is that an underlying cylindrical rod contacts the sample material being tested at 20 contact points. If the filter is long enough to extend across the underlying rod, then the 20 contact points can be provided for 10 samples (as shown in Figure 4). If the filter is not long enough, then the 20 contact points can be provided for 20 samples, as shown in Figure 5.

[0089] As can be seen in Figure 5, a portion of the tobacco rod is removed from each smoking article 10, and the filter portion of each smoking article 10 remains on the respective cylindrical rod 14. If present, the stiffness of the mouth end segment has been tested, and it is therefore this portion of the filter that remains on the rod 14, and the mouth end segment is approximately centered on the rod 14. If necessary, the tip of the smoking article that extends away from the cylindrical rod 14 may be supported by an underlying support means to prevent rotation of the smoking article.

[0090] The apparatus is shown in Figure 5 in a first configuration in which the two load-applying cylindrical rods 24 are raised above and out of contact with the smoking article 10. To test the firmness of a smoking article, the load-applying cylindrical rods 24 are lowered to a second configuration, as shown in Figure 6, so that they come into contact with the smoking article 10. Upon contact with the smoking article 10, the load-applying rods 24 apply a total load of 2 kg across the 20 contact points on the smoking article 10 for 20 seconds. After the 20 seconds have elapsed (and the load is still applied to the smoking article), the depression of the load-applying cylindrical rods 24 across the smoking article is determined and then used to calculate the firmness.

[0091] Figure 7 is a graph showing the stiffness (%) for six types of smoking article filters, both smoked and unsmoked, in which each filter was incorporated into a smoking article and subjected to the DD60A test described above and illustrated by Figures 4-6.

[0092] The six types of smoking article filters tested (using the methods and apparatus described above) were: Filter Type A :About 26gm -2 and a filter length of 21 mm and a cigarette filter having a filter wrapper basis weight of about 26 gm -2 and a filter length of 27 mm. In both cases, the smoking article diameter is 7.84 mm, the filter wrapper thickness is 40 μm, and the tipping material thickness is 40 μm. Both of these sets of data are shown as white bars in Figure 7, with a 21 mm filter on the left side of Figure 7 and a 27 mm filter on the right side of Figure 7.

[0093] Filter Type B :About 78gm -2 and a filter length of 21 mm and a filter according to the present invention having a filter wrapper basis weight of about 78 gm -2and a filter length of 27 mm. In both cases, the smoking article diameter is 7.84 mm, the filter wrapper thickness is 100 μm, and the tipping material thickness is 40 μm. Both of these sets of data are shown in Figure 7 as light grey bars, with a 21 mm filter on the left side of Figure 7 and a 27 mm filter on the right side of Figure 7.

[0094] Filter Type C :About 110gm -2 and a filter length of 21 mm and a cigarette filter having a filter wrapper basis weight of about 110 gm -2 and a filter length of 27 mm. In both cases, the smoking article diameter is 7.84 mm, the filter wrapper thickness is 140 μm, and the tipping material is 40 μm. Both of these sets of data are shown in Figure 7 as dark gray bars, with a 21 mm filter on the left side of Figure 7 and a 27 mm filter on the right side of Figure 7.

[0095] As can be seen from Figure 7, there is little difference in stiffness between the 21 mm and 27 mm filters. Additionally, as can be seen from Figure 7, there is little difference in stiffness between the pumped and unpumped filters.

[0096] However, as can be seen from Figure 7, smoking article filter stiffness tends to increase as the basis weight of the filter wrapper increases. -2 Basis weight filter and 78gm -2 The average increase in firmness between the gm basis weight filters was found to be 6.50%, which is -2 Each increase represents a 0.125% increase. However, 78gm -2 Basis weight filter and 110gm -2 The average increase in stiffness between the gm basis weight filters was found to be 1.91%, which is -2Each increase represents an increase of only 0.060%.

[0097] Therefore, the relationship between basis weight and stiffness is not linear, and stiffness tends to increase relatively more at lower basis weight levels. -2 It has been recognized that the use of a filter wrapper having a basis weight of 1000 mg / m² provides a sufficient increase in stiffness while avoiding the need for a very stiff filter wrapper, which may be more difficult to manufacture.

[0098] The hardness of various types of filter rods (when not incorporated into a smoking article) was also tested using a DD60A Densimeter (manufactured and sold by Heinr. Borgwaldt GmbH, Germany) fitted with a measuring head for cigarettes and a cigarette receptacle as described above, and following the DD60A test method described above.

[0099] Figure 8 is a graph showing the hardness (%) of six types of smoking article filters. In Figure 8, each filter was not incorporated into a smoking article. The six types of smoking article filters tested (using the apparatus and methodology described above) were the same as in Figure 7, namely: Filter Type A :About 26gm -2 and filter lengths of 21 mm / 27 mm. In both cases, the filter wrapper thickness is 40 μm. Both of these sets of data are shown as white bars in Figure 8, with the 21 mm filter on the left and the 27 mm filter on the right.

[0100] Filter Type B :About 78gm -2and filter lengths of 21 mm / 27 mm. In both cases, the thickness of the filter wrapper is 100 μm. Both of these sets of data are shown in FIG. 8 as light grey bars, with the 21 mm filter on the left side and the 27 mm filter on the right side.

[0101] Filter Type C :About 110gm -2 and filter lengths of 21 mm / 27 mm. In both cases, the filter wrapper thickness is 140 μm. Both of these sets of data are shown in Figure 8 as dark gray bars, with the 21 mm filter on the left and the 27 mm filter on the right.

[0102] Just as in Figure 7, in Figure 8, smoking article filter stiffness tends to increase as the filter wrapper basis weight increases, but the relationship between basis weight and stiffness is not linear. -2 It has been recognized that the use of a filter wrapper having a basis weight of 1000 psi provides a sufficient increase in stiffness while avoiding the need for a very stiff filter wrapper, which may be more difficult to manufacture.

[0103] As noted above, the inventors of the present invention have considered that it is preferable for the mouth end of the smoking article filter to have an ovality of less than about 25% after a 50% deformation, both before and after smoking, so that a consumer can enjoy a smoking experience after biting the mouth end of the smoking article filter.

[0104] The ovality of various types of smoking articles was tested using the above method. That is, the smoking article was subjected to deformation, and then the mouth end of the smoking article was recorded using a transparent base. The process was repeated for 10 smoking articles and averaged.

[0105] Figures 9 and 10 are graphs showing the ovality (%) for three types of smoking article filters, both drawn and undrawn.

[0106] With reference to Figures 9 and 10, "1 / 3 compression" means that the mouth end of the smoking article is deformed to 66.67% of its original diameter (i.e., compressed to 1 / 3) and then released, "1 / 2 compression" means that the mouth end of the smoking article is deformed to 50% of its original diameter (i.e., compressed to 1 / 2) and then released, and "2 / 3 compression" means that the mouth end of the smoking article is deformed to 33.33% of its original diameter (i.e., compressed to 2 / 3) and then released.

[0107] The three types of smoking article filters tested (using the apparatus described above) were: Filter Type A: Approx. 26g -2 a filter wrapper basis weight of 1.00, a filter length of 27 mm, a smoking article diameter of 7.84 mm, a filter wrapper thickness of 40 μm, and a tipping material thickness of 40 μm. Both of these sets of data are shown by the black lines, for an undrawn filter in Figure 9 and a drawn filter in Figure 10.

[0108] Filter Type B: Approx. 78g -2 a filter according to the invention having a filter wrapper basis weight of 100 μm, a filter length of 27 mm, a smoking article diameter of 7.84 mm, a filter wrapper thickness of 100 μm and a tipping material thickness of 40 μm. Both of these sets of data are shown by dark grey lines for the undrawn filter in Figure 9 and the drawn filter in Figure 10.

[0109] Filter Type C: Approx. 110g -2 a filter wrapper basis weight of 1.00, a filter length of 27 mm, a smoking article diameter of 7.84 mm, a filter wrapper thickness of 140 μm, and a tipping material thickness of 40 μm. Both of these sets of data are shown as light grey lines, with an undrawn filter in Figure 9 and a drawn filter in Figure 10.

[0110] As can be seen from Figures 9 and 10, the ovality of the smoking article tends to increase after compression as the basis weight of the filter wrapper increases, but just like stiffness, the relationship does not appear to be linear.

[0111] It would be preferable for the mouth edge to return to a perfect circle (0% ovality) after deformation, the closest equivalent being a filter type A cigarette filter (filter wrapper basis weight of approximately 26 gm -2 , it has the lowest ovality values ​​overall in Figures 9 and 10. However, it can be seen from Figures 7 and 8 that such a filter wrapper does not have a high hardness value and therefore does not provide sufficient resistance to deformation for an enjoyable chewing experience for the consumer. The inventors found that approximately 78 gm -2 It has been recognized that the use of a filter wrapper having a basis weight of 1000 mg / g provides a sufficient increase in firmness while limiting the increase in ovality after chewing.

[0112] Thus, smoking articles and filters according to this embodiment of the invention provide increased hardness for an enjoyable chewing experience, but reduced ovality after chewing for an enjoyable smoking experience, even after chewing. This provides an excellent balance between an enjoyable chewing and smoking experience.

Claims

1. 1. A smoking article comprising: an aerosol-forming substrate that is tobacco-free; a filter including a plug of filtration material defining a downstream end segment of the smoking article, the plug being surrounded by one or more filter wrappers; and a tipping material adhering the aerosol-forming substrate and the filter; Including, the stiffness of the smoking article at the downstream terminal segment is at least about 90%, the stiffness being the ratio of the diameter of the downstream terminal segment after application of a load to the diameter of the downstream terminal segment before application of a load; The load is achieved by applying a 2 kg load from the upper rods to the upper contact points for 20 seconds in an arrangement in which 10 or 20 smoking articles having a temperature of 20 to 24 degrees Celsius are placed on two parallel lower rods, thereby resulting in 20 lower contact points between the lower rods and the smoking articles, and two parallel upper rods are placed on the smoking articles, thereby resulting in 20 upper contact points between the upper rods and the smoking articles, each of which corresponds to the position of the lower contact point; A smoking article wherein the filtration material extends to the furthest downstream end of the filter; and the one or more filter wrappers have a basis weight of between about 50 grams per square meter and about 100 grams per square meter.

2. 10. The smoking article of claim 1, wherein the one or more filter wrappers have a basis weight of between about 70 grams per square meter and about 80 grams per square meter.

3. 3. A smoking article according to any one of claims 1 to 2, wherein the hardness of the smoking article at the downstream end segment is at least about 92%.

4. 4. A smoking article according to any one of claims 1 to 3, wherein the hardness of the smoking article at the downstream end segment is about 94% or less.

5. A smoking article as described in any one of claims 1 to 4, wherein the ovality of the farthest downstream end of the smoking article is less than about 25% after 50% deformation of the farthest downstream end of the smoking article.

6. A smoking article as described in any one of claims 1 to 5, wherein the ovality of the farthest downstream end of the smoking article is less than about 25% after a 50% deformation of the farthest downstream end of the smoking article, performed after the smoking article is subjected to a smoking test.

7. 7. A smoking article according to any one of claims 1 to 6, wherein the one or more filter wrappers have a bending stiffness in the longitudinal direction of the filter wrapper of at least about 0.08 N.

8. 8. A smoking article according to any one of claims 1 to 7, wherein the one or more filter wrappers have a bending stiffness of at least about 0.04 N in a transverse direction of the filter wrapper.

9. 9. A smoking article according to any one of claims 1 to 8, wherein the filter comprises a filtration material extending along the entire length of the filter.

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