PT2552260E - Filter cigarette with variable ventilation - Google Patents

Description

DESCRIPTION

CIGARETTE PAPER WITH CHAINED BANDS

STATE OF THE TECHNIQUE

There have been attempts to design smoking articles that are extinguished when inadvertently left unattended on a substrate, and the tendency to do so is referred to herein as a smoking article having " low propensity for ignition ". Ideally, an article for low-ignition propensity smoking will continue to burn when freely suspended, such as in an ashtray holder or when it is in the hand without aspiration (" free burning "). The tendency for a cigarette to extinguish during free combustion is referred to herein as " self-extinguishment ". Many prior cigarette designs that achieve low propensity characteristics exhibit high rates of self-extinguishment under free-combustion conditions. US 2004/0261805 AI discloses various cigarette wrappers, each comprising one or more bands of additive material to adjust the porosity of the wrapper and to control the burning rate of the cigarette.

SUMMARY

A wrapping for a smoking article of the present invention comprises a web having a nominal permeability and a plurality of spaced apart web regions each comprising sufficient accessory material such that the wrapping has a permeability in the web region lower than the nominal permeability of the base web. The casing is characterized in that one leading edge of each striped region as viewed by an advanced coal is pounded, and a trailing edge of each striped region is pounded. The width of a continuous portion of each band region between the bottom of the main rim nests and the bottom of the trailing edge niches is less than a spacing between the peaks of the trailing edge merlons and the peaks of the trailing edges the main edge of the region with subsequent bands.

BRIEF DESCRIPTION OF THE DRAWINGS

Many objects and advantages of the present specification will be apparent to those skilled in the art when this disclosure is read in conjunction with the accompanying drawings, wherein like reference numerals are applied to like elements and wherein: FIG. 1 is a perspective view of a smoking article according to the present specification; FIG. 2 is a schematic view of a paper wrapper having a first embodiment of a region with ample bands; FIG. 3 is a schematic view of a paper wrapping with a second embodiment of a region with ample bands; FIG. 4 is a schematic view of a paper wrapper with a third embodiment of a region with ample bands; FIG. 5 is a schematic view of a paper wrapper with a fourth embodiment of a region with ample bands; FIG. 6 is a schematic view of a paper wrapping with a fifth embodiment of a region with ample bands.

DETAILED DESCRIPTION

According to the present disclosure, a smoking article 1 includes a tobacco rod 2. The tobacco rod 2 may include a fragmented tobacco filler 3 and is surrounded by a paper wrapper 10. One end of the smoking article may include a suitable filter 4 surrounded by suitable filter perforated paper. The smoking article 1 may typically have a generally circular cross-section along the length of the smoking article. However, other cross-sectional shapes, including, for example, oval, are within the scope of this disclosure. The tobacco rod 2 has a nominal length measured from the perforated paper to the free end of the tobacco rod along a longitudinal axis of the smoking article. By way of example, this nominal length may vary from about 60 mm to about 100 mm. The paper wrapper 10 includes a base web, which is typically air permeable. The permeability of the paper wrapper is usually identified in Coresta units. A Coresta unit measures the permeability of paper in terms of volumetric flow rate (i.e., cm 3 / sec) per unit area (i.e., cm 2) per unit of pressure drop (i.e. cm water). The base web for a conventional paper wrap also has well known basis weights, measured in grams per square meter, abbreviated as " gsm ". The permeability and basis weight for the paper web of typical smoking articles commonly used in the industry are set forth in the table below:

Permeability, Units Coresta Base weight, gsm 24 25 33 25 46 25 60 26

For purposes of this disclosure, the web of a preferred paper wrapper has a permeability of at least about 20 Coresta units. Most preferably, the paper wrapper has a permeability of greater than about 30 Coresta, such as common base webs, having nominal permeabilities of about 33 and about 46 Coresta, having a basis weight of about 25 gsm. For some applications, the web base may have a permeability of greater than about 60 Coresta, or greater than about 80 Coresta or even higher permeability values.

It should be noted from the point of view of convention that, in the present description of dimensions of various embodiments, " width " of a banded region extends in a longitudinal direction of the tobacco rod, while a dimension in the circumferential direction of a banded region will be expressed as " transverse " or " in the transverse direction " of " transverse direction of the web ".

For the purposes of this description, regions with bands of accessory material as described herein are applied to the paper wrapper to obtain better ignition propensity characteristics and also to achieve an improvement in the self-extinguishing characteristics. Propensity for ignition is a standard test performed as described in ASTM E2187-04, " Standard Test Method for Measuring Ignition Propensity in Smoking Articles ", which is presently incorporated in its entirety by this reference. The propensity for ignition measures the likelihood that a smoking article when placed on a substrate will generate enough heat to maintain the static burning of the tobacco rod. Low values for the propensity for ignition are desirable since such values correlate with a reduced likelihood that a smokeless smoking article will cause combustion on an underlying substrate. Self-extinguishing is a reference herein for slow combustion characteristics of a smoking article under free combustion conditions. To evaluate self-extinguishment, a laboratory test at a temperature of 23 ° C ± 3 ° C and relative humidity of 55% ± 5% shall be conducted, both of which shall be monitored by a recording hygrothermograph. Exhaust fan (s) removes the combustion products formed during the tests. Prior to testing, the smoking articles to be tested are conditioned at 55% ± 5% relative humidity and 23 ° C ± 3 ° C for 24 hours. Immediately before the test, smoking articles are placed in glass beakers to ensure free access to the air.

Self-extinguishing tests take place within an enclosure or test box. A single door smoking machine or an electric cigarette lighter is used to inflame smoking articles for testing. During the test, an apparatus or " angle bracket " supports smoking articles to be tested, with an end at 0 degrees (horizontal), 45 degrees, and / or 90 degrees (vertical). Twenty (20) smoking articles are tested in each of the 0 degree, 45 degree and 90 degree positions. If more than one apparatus is used, they are preferably positioned such that the smoking articles are spaced from each other to avoid cross-interference. If a smoking article extinguishes before the front line of the latent coal reaches the perforated paper, the result is marked as " self-extinguishing "; on the other hand, if the smoking article remains latent until the latent coal front line reaches the perforated paper, then the result is marked as " non-quenching ". Thus, for example, a 95% self-extinguishing value indicates that 95% of the smoking products tested exhibited self-extinguishment under free-combustion conditions; while a self-extinguishing value of 20% indicates that only 20% of the smoking products tested exhibited self-extinguishment under free-combustion conditions. The self-extinguishing value can be referred to in terms of " self-extinguishment value of 0 degrees ", " self-extinguishment value of 45 degrees " or " self-extinguishment value of 90 degrees " each of which refers to the self-extinguishment value, with the specified tested angle. Further, the self-extinguishing value may be referred to in terms of " self-extinction average value ", which refers to the average of the three angular positions, i.e., a mean of (i) " self-extinguishment value of 0 degrees ", (ii) " self-extinguishment value of 45 degrees ", and (iii) " self-extinguishment value of 90 degrees ". The reference to " self-extinguishing value " does not distinguish between self-extinguishment at 0 degrees, self-extinction at 45 degrees, self-extinction at 90 degrees or mean values of self-extinguishment and may refer to any one of them.

The phrases " self-extinguishing under free-combustion conditions " or " self-extinguishing under free-combustion conditions ", as used herein, refers to the quenching of a lit cigarette, without being smoked, when such a cigarette is subjected to or exposed to free-combustion conditions. The term " corrugated " as used herein to describe the leading edge of a striped region means that the leading edge has a wave-like shape. The wave-like shape can be curved or composed of segments of straight lines, including square or rectangular, and the words encompass " flared ". As used herein, the term " refers to a pattern of geometrically spaced, regularly spaced spaces removed from another continuous solid band region. A puffed pattern or puffed band may also be described as notched or looking like a pulsed wave. As used herein, " battlements " refer to openings or valleys, on a rimmed rim, while " merlons " refer to embossed portions, or plateaus of a rim with battlements, between the battlements.

As used herein, the phrase " leading edge " refers to the edge of a banded region which is closer to a approaching coal during the slow combustion of a smoking product, which casing contains the striped region, while the term " trailing edge " refers to the edge of a striped region which is further away from an approaching coal during the slow combustion of a smoking article whose casing contains the striped region. In ambered embodiments, the overall width " W " of the banded region is measured from the forward extension furthest from the main rim to the towing extension furthest from the trailing edge, as is shown in FIG. 6 with the width " W ".

A wrapping for a smoking article comprises a base web 10 (see FIG 2) having a nominal permeability and a plurality of strip regions 12 with sufficient accessory material such that the wrapper has a permeability in the region with lower webs to the nominal permeability of the base web. The leading edge 14 of each striped region 12 is crimped and a pulling tassel 16 of each striped region is also crimped.

While various arrangements of the pomegranate regions may occur to those skilled in the art, a number of such arrangements are illustrated in the accompanying drawings. For example (see Figure 2), the web region 12 may have a main flange 14, where the nests 20 are placed between merlons 18. In this embodiment, the merlons 18 have a dimension in the transverse direction of the base web 10, which is substantially the same as the transverse dimension of the crenels 20. As shown, the crenels 18 and associated crenels 20 may be generally rectangular. If desired, however, the merlons 18 and battlements 20 may have other geometric shapes, including, without limitation, quatlars, trapezoids, triangles, hexagons and other regular or irregular geometric configurations. The distance between the top of a merlin 18 and the bottom of an adjacent niche 20 may range from about 2 mm to about 5 mm, and preferably may be about 3 mm.

At the trailing edge of the band region 12, a similar ply arrangement is also provided. To this end, a plurality of merlons 22 may be transversely spaced through the base web 10 and separated from each other by a corresponding plurality of crenels 24. As shown, the major edge merlons 18 are aligned transversely with the edge crenels 24 and the rims 20 of the main rim are aligned transversely with the rims 22 of the trailing edge. The battlements 24 have a transverse dimension to the web substantially the same as the transverse dimension of the web of the merlons 18 in the main rim 14 of the web. Similarly, the merriments 33 of the trailing edge 16 may have a transverse dimension to the web substantially the same as the dimension transverse to the meristems web 20 of the main flange 14. The distance between the top of a merlin 22 and the bottom of a adjacent to the trailing edge 24 may also range from about 2 mm to about 5 mm, and preferably may be about 3 mm. As with the merlons 18 and battlements 20 of the main flange 14, the merlons 22 and the trailing edge battlements 24 may be generally rectangular, generally quadrilateral, generally trapezoidal, generally triangular, generally hexagonal, or other geometric configurations. The lower portion 21 of the battlements 20 of the main flange 14 is preferably spaced from the bottom 25 of the trailing edge battlements 24 by a distance x having a range of about 2 mm to about 5 mm, and preferably a variation of about 3 mm to about 4 mm. With such an arrangement, a substantially continuous web portion of width x extends transversely through the base web 10. The bottom portion 21 of the main edge notches 20 corresponds to a major edge of the substantially continuous web portion " , while the lower portion of the trailing edge battlements 24 corresponds to a trailing edge of the substantially continuous band portion ". ". The web portion " x " will provide a region of the base web where the paper wrapping of the smoking articles experiences relatively less access to air as compared to regions that do not have accessory material. Therefore, the distance " x " can be adjusted to achieve a desired balance of propensity performance for ignition and self-extinguishing performance.

Adjacent web regions 12 and 12 'of the paper web 10 are spaced longitudinally from one another by a nominal spacing. This nominal spacing " S " (measured between the recessed point of a trailing edge 16 for the forward extension of the nearest major rim 14) may range from about 10 mm to about 30 mm. In particular, the band period, which may be dependent on the length of the smoking rod of the smoking article, may be about 27 mm, i.e., the nominal spacing would be about 27 mm less the width of the crimped band. The spacing minimizes the total coated area (i.e., the area containing accessory material) in a smoking article, thereby reducing the carbon monoxide (CO) levels of the main stream of smoke. Although the depth of the battlements 20 on the leading edge of the band region 12 and the depth of the battlements 24 on the trailing edge of the band region 12 is shown in FIG. 2 as being the same, it is within the scope of the present specification to make such different depths, if desired.

The transverse orientation dimensions of the merlons 18, 22 and the nylons 20, 24 may be substantially the same, as shown in FIG. 2. Preferably, however, a full number of pairs of merlons 18 and nests 20 have a cross-sectional dimension corresponding to the nominal circumference of a smoking article. For example, two sets of merlons 18 and battlements 20 may have transverse dimensions to the web of about 6.2 mm, so that two pairs each have a transverse dimension to the total web of about 24.8 mm, which corresponds to the nominal circumference of a smoking article. With such a sizing for the merlons and nests, when the base web 10 is divided longitudinally to form coils of the paper wrapping for smoking articles, for example, on the lines 30, 32, the smoothed pattern of the band region 12 will overlap, substantially and perfectly in a longitudinal seam making the tobacco rod.

Stated differently, in establishing a printing pattern for a roll of penned (or sawtooth) paper, the pattern should be repeated through the roll according to a transverse dimension equal to the nominal circumference of the cigarette which is supporting the pattern , even though the roll can be cut to a size slightly larger than the nominal circumference of the cigarette (to provide seam portions for the seam along the tobacco rod). This practice will ensure the establishment of the pattern as intended in the cigarette, regardless of where the cut is started, or the dimensions of the seam. For example, if the cigarette is to have a pattern of eight (8) merlons (or teeth) and the cigarette is to have a nominal circumference of the cigarette of 24.8 mm, the roll of penned (or sawtooth) would be cut every 27 mm, but the pattern of eight (8) merlons (or teeth) would repeat every 24.8 mm.

Turning to FIG. 3, the proportions of the merlons 44 and the merlons 46 of the main flange 40 are different from the arrangement of FIG. In FIG. 3, the merlons 44 may have a transverse dimension of the web about one-half the dimension transverse to the associated meridian web 46. However, an integral number of meritor pairs 44 and meridians 46 corresponds to the nominal circumference of the meridian 46. article for smoking, as discussed above. The height of the merlons 44, or the depth of the merlons 46, is preferably in the same range of values as discussed in connection with FIG. 2.

At the trailing edge of the embodiment of FIG. 3, the dimensions transverse to the web of the trailing edge merlons 50 and the trailing edge meridians 48 are different from the dimensions transverse to the web of the merlons of the main flange 44 and of the merins of the main flange 46. Here again, however, an integral number of the set of merlons 48 and nests 50 has a dimension transverse to the web corresponding to the nominal circumference of a smoking article. As shown, the cross-sectional dimension of the crenels web 48 is substantially less than the cross-sectional dimension of the webs of the merlons 44 on the opposing portion of the main flange 40. Moreover, the depth of the crenels 48 or the height of the merlons 50 are, in the range of dimensions discussed above, in connection with FIG. 2. Furthermore, the spacing between the bottom of the crenels 46 on the main flange and the bottom of the crenels 48 on the trailing edge also lies in the size range discussed above in connection with FIG. 2. The spacing between adjacent band regions 12 in FIG. 3 is also in the same range discussed above in connection with FIG. 2.

Turning to FIG. 4, the leading edge 14 of the band region 12 may have substantially the same characteristics discussed above, in connection with FIG. 2. However, the trailing edge 64 may have webs 60 which are transverse to the web substantially larger than the dimensions transverse to the web of the opposing webs 20 of the main web, while the dimensions transverse to the web of the webs of the trailing edge 62 are substantially less than the web-transverse dimensions of the corresponding opposing merlons 18 of the main flange 14. The spacing between the main flange and the trailing edge flared in FIG. 4, and a longitudinal spacing between adjacent band regions 12 of FIG. 4 is substantially the same as described above in connection with FIG. 2.

The main edge merlons may have a transverse dimension varying from 3 mm to about 7 mm. For example, the leading edge merlons may have a transverse dimension of about 3.1 mm, about 4.2 mm or about 6.2 mm. The main edge battlements may have a transverse dimension ranging from about 3 mm to about 7 mm. For example, the leading edge battlements may have a transverse dimension of about 3.1 mm, about 4.2 mm, about 5.2 mm or about 6.2 mm. The trailing edge merlons may have a transverse dimension ranging from about 6 mm to about 10 mm. For example, trailing edge merlons may have a transverse dimension of about 5.775 mm, about 6.2 mm or about 6.775 mm. The trailing edge marriages may have a transverse dimension ranging from about 1 mm to about 7 mm. For example, the trailing edge crenels may have a transverse dimension of about 1 mm, about 2.1 mm or about 6.2 mm.

While the foregoing embodiments illustrate crimped edges having a traditional toothed shape, the crimped web 12 of FIG. 5 has a different shape for the flared flanges 80. More particularly, the flanged flange 80 has merlons 18 which are substantially triangular. The triangular merlons 18 are separated by, and define, substantially triangular meridians 20. If desired, the traction edge 82 of the web may be straight. Preferably, however, the trailing edge 82 of the web 12 may also have the triangular-mesh configuration described above in connection with the main flange 80. Significantly, the lower portions of the flared main flange 20 are spaced longitudinally along the paper web 10 from the lower portions of the trailing edge battlements 20 'by a distance w. Another important feature is that the longitudinal spacing S between the peaks of the trailing edge merlons 82 and the peaks of the subsequent major edge merlons 80 'is greater than the width w of the continuous portion of each web 12.

It is believed that the triangular puffed bands 12 function as a conventional band in the w region. The nests connected with the longitudinal inter-band spacing S cooperate to reduce the carbon monoxide component in the smoke of a smoking article formed from this paper wrapper. Furthermore, by selecting the transverse spacing to the web z between the peaks of an integral number of merlons to match the circumference of a smoking article to be fabricated with the paper web 10, the paper web 10 can be cut lengthwise without worry with the location of the cuts and the paper web 10 will superimpose substantially and precisely on a longitudinal seam of the paper wrapper. Z spacing may also be adjusted to achieve a desired balance of propensity performance for ignition and self-extinguishing performance for the smoking article.

Similar to the crimped band of FIG. 5, the crimped band 12 of FIG. 6 has a crimped flange 80 with merlons 18 which are substantially triangular, triangular merlons 18 separated by and defining substantially triangular merlons 20. While, the traction edge 82 of the web can be straight, in FIG. 6, the trailing edge 82 of the web also has the same triangular pinhole configuration as the main flange 80. As further shown in FIG. 6, the web may be divided into two web portions 112, 112 'which are spaced from each other by a " slot " 81. The slot 81 typically does not exceed the width of the individual band portions 112, 112 'as measured in a direction generally parallel to the axis of a smoking article with the bands. The spacing feature provides a " slit " 81 (or discontinuity) in the web structure where there is less or no accessory material.

A smoking article may comprise a tobacco rod and a wrapper, as described herein. The wrapper preferably has a transverse dimension which takes into account a circumference of the tobacco rod and an overlapping seam. As a result, regardless of where the casing is cut, when the smoking article is formed, there is always an exact overlap of the smoothed pattern. In other words, the transverse dimensions of the merlons and nests of the banded region are determined in such a way that in the article for smoking the main edge of the banded region preferably comprises at least two nests and, at least , two merlões. For example, the leading edge of the striped region may comprise two meridians and two merlons, three merlons and three merlons, or four merlons and four merlons. Thus, regardless of how the smoking article is placed on a substrate during the ASTM test, there is always symmetry of the banded region. Without wishing to be bound by any theory, it is believed that as the smoking article remains in the substrate during slow combustion, combustion is modulated by the main flank crimped; specifically, leading edge merlons reduce the progression of slow combustion while mainline merlons allow a limited amount of slow combustion to continue during free combustion conditions. Therefore, the self-extinguishing and propensity characteristics for ignition are achievable.

As currently understood, regions with bands of the accessory material according to this disclosure enable the design of a smoking article with an advantageous combination of low propensity values for ignition and low self-extinguishment values. The low permeability of the strip regions of the accessory material provides areas of film-forming compound along the length of the tobacco rod, which may cooperate with a substrate to quench the smoking article when it is placed on a substrate, but such areas of film-forming compound do not cause self-extinguishment of the smoking article when the smoking article is used by a smoker in a free-burning condition. Thus, the smoking article may exhibit a reduced ignition tendency while maintaining a desirable free-burning or low-self-extinguishing quality by applying regions with film-forming compound webs to the web according to this disclosure. The accessory material may be applied to one or both sides of the base web.

To achieve the desirable ignition propensity and self-extinguishing characteristics of the smoking article, web regions are applied to the web of the paper wrapper web. An object of the present disclosure is to provide paper wrappers which, when formed in a tobacco rod, exhibit propensity values for ignition of not more than 25 and self-extinguishing values not greater than 50. Still more preferred is a propensity value for the ignition for the resulting smoking article does not exceed about 15; and a more preferred value of ignition propensity for the resulting smoking article not to exceed about 10. Low self-extinguishing values are also desired. In this regard, a more preferred self-extinguishing value is less than about 25; while the most preferred self-extinguishing value is less than about 10.

The transverse dimensions of the paper wrapper are selected based on the diameter of the finished smoking article (about 7 mm to about 10 mm) and allowing overlap in a longitudinal seam of about 1 mm to about 2 mm. For example, by allowing overlapping seams of 1 mm, the size of the paper wrap in the transverse direction may be about 27 mm for a smoking article having a circumference of about 25.6 mm.

Band regions may be formed by applying one or more layers of a composition that forms an aqueous film to the web of the paper wrapper to reduce the permeability of the paper in such web regions.

Alternatively, a cellulosic material may also be used to form the band regions. Where a film forming composition is used, such film forming composition may preferably include water and a high concentration of an occluding agent, for example 20% to about 50% by weight. The film-forming compound may include one or more occlusion agents, such as starch, alginate, cellulose or gum, and may also include calcium carbonate as a filler. When the starch is the film-forming compound, a concentration of about 24% may be advantageous. The film forming composition may be applied to the web of the paper wrapper 24, using an engraving, digital printing, coating or spraying printing using a mold or any other suitable technique. For example, the film forming compounds and methods for applying film forming compounds disclosed in U.S. Application Publication 2007/0102017 AI may be chosen for the application of web regions to the web of the paper wrapper. If desired, regions with bands of accessory material may be formed by printing multiple, successive layers, for example, two or more successive layers recorded or aligned with one another. Further, when the layers are used to form the regions with bands of accessory material, the layered material may be the same or different. For example, one layer may be starch while the next layer may be starch and calcium carbonate.

Additionally, the ability to extinguish the smoking article may depend more on the longitudinal delivery of a minimal extent of the film-forming compound, rather than a certain weight per area of the film-forming compound. The amount of the film-forming compound used can be increased without losing the free-burning quality if a combustion accelerator is applied to the paper. Preferably, regions with bands of accessory material reduce the permeability of the paper wrapper to the range of from about 0 to about 10 Coresta.

A multi-stage printing apparatus, as presently described, generally includes a reel, a first gravure printing station, a second gravure printing station, a third gravure printing station, a collection of spools, rollers, printing, support roll, pinch, reservoir, pump, heat exchanger, applicator, bath, manifold, drain, scraper blade, adjusting cylinders and tensioning roller.

As an alternative to a gravure printing operation, the striped or striped regions can be applied to a base web using the same cellulosic material forming the base web. The strip regions may comprise a highly refined fibrous cellulose pulp (e.g., fibers, fibrils, microfibrils or combinations thereof) or other applied accessory material, using various spraying or coating techniques, including application techniques using an applicator of moving holes in the forming section of a papermaking machine as described in commonly owned US 5 997 691 and US 6 596 125.

Although in the past this technology has been used to circumferentially pattern the strip regions by adjusting the relative movement between the paper web and the moving orifice strip of the apparatus described in commonly owned US 5 997 691 and US 6 596 125, the striped regions of this disclosure may readily be formed. It is recognized that such an arrangement operates the orifice device in motion at a slower belt speed which is conducive to the application of broader bands and higher rates of application.

The terms and phrases used here should not be interpreted with mathematical or geometrical precision, a geometrical terminology should instead be interpreted as roughly or similar to geometric terms and concepts. Terms such as " generally " are intended to encompass both the precise meanings of the terms and associated concepts as well as to provide reasonable latitude that is consistent with form, function, and / or meaning. The term " about ", when used in connection with numerical quantities is intended to include values within a tolerance of 10% of the amounts declared.

While various embodiments have been described, it is to be understood that various modifications, variations, and equivalents may be invoked as will be apparent to those skilled in the art. Such modifications, variations and equivalents should be considered within the scope of the appended claims.

Lisbon, July 17, 2015

Claims (8)

A wrapping for a smoking article (1), comprising: a base web (10) with a nominal permeability, a plurality of spaced apart strip regions (12), each striped region comprising sufficient accessory material therefor so that the shell has a permeability in the striped region less than the nominal permeability of the base web, characterized in that a leading edge (40) of each striped region is crimped and a trailing edge (16) of each striped region is crimped, and wherein the width of a continuous portion of each striped region between the bottom of the main rim nodes (14) (40) and the lower portion of the trailing edge cords (16) (42) is less than a spacing between the peaks of the trailing edge merlons (16) (42) and the peaks of the major edge (14) (40) of the subsequent banded region. A casing according to claim 1, wherein in a region with strips (12) the merles (18) of the main flange (40) are aligned transversely with the flanges (24) (48) of the flange (16) (42) and the rims (20) (46) of the main edge are aligned transversely with the trailing edge merriments (22) (50). A smoking article (1) comprising a tobacco rod (2) and a wrapper according to claim 1 or 2. A smoking article (1) according to claim 3, wherein in a striped region (12) the main edge crenels (20) and the trailing edge merlons (18) have transverse dimensions which are substantially the same. A smoking article (1) according to claim 4, wherein the merlons (18) (44) of a main flange (14) (40) reduce the progression of slow burning of the smoking article. A smoking article (1) as claimed in claim 4 or 5, wherein the merlons (18) (44) of a main flange (14) (40) reduce the slow combustion progression of the smoking article as far as wherein the smoking article on remains on a substrate. A smoking article (1) according to claim 4, 5 or 6, characterized in that the apertures (20) (46) of a main flange (14) (40) allow a limited amount of slow combustion which continues during the conditions. A smoking article (1) according to any of claims 4 to 7, wherein a main flange (40) comprises at least two crenels (20) (46) and at least two merlons ( 18) (44). Lisbon, July 17, 2015