Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D1/00—Cigars; Cigarettes
  • A24D1/02—Cigars; Cigarettes with special covers
  • A24D1/025—Cigars; Cigarettes with special covers the covers having material applied to defined areas, e.g. bands for reducing the ignition propensity
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D1/00—Cigars; Cigarettes
  • A24D1/10—Cigars; Cigarettes with extinguishers

Definitions

• This disclosure relates generally to a smoking article and, more particularly, a smoking article having a pattern provided on the wrapping paper for reducing ignition propensity of the burning smoking article when left unattended upon a substrate.
• a smoking article includes a tobacco rod with a wrapper paper formed from a base web having a nominal permeability. Zones of add-on material are preferably applied to the base web according to a pattern that includes a plurality of circumferentially spaced regions that are longitudinally spaced along the tobacco rod. Each of the regions preferably includes at least two substantially opposed zones of add-on material, which zones exhibit a permeability less than the nominal permeability.
• the zones of add-on material preferably have sufficient size, shape, and add-on material concentration that, when the tobacco rod is smoldering and is placed on a substrate, that the tobacco rod will tend to extinguish at the corresponding region. For each first, second, and third consecutive region, the zones of the second region are circumferentially offset from the zones of the first region. Moreover, the zones of the third region are circumferentially offset from the zones of both the first and second regions.
• the pattern preferably continues substantially along the tobacco rod so that, when the tobacco rod is placed on a substrate and viewed from an end, at least one region will be situated such that its zones of add-on material are positioned substantially at side portions of the tobacco rod.
• the smoking article preferably exhibits an Ignition Propensity no greater than about 25% and a self-extinguishment value no greater than about 50%.
• a smoking article according to this disclosure preferably includes a wrapper paper having a pattern formed by a permeability reducing film-forming compound.
• the pattern is selected so that when the smoking article is placed on a substrate, the smoking article will self- extinguish when an advancing burn line reaches one or more longitudinal locations where film- forming compound is present at sides of the smoking article not in contact with a substrate but those sides having film-forming compound or agent will not cause the smoking article to self- extinguish when the smoking article is held by a smoker.
• a pattern may be selected that takes into account the obstructed airflow through the side or side portion of the smoking article that contacts a substrate. By doing so, a smoking article may have both a reduced ignition propensity and satisfactory free-bum quality.
• the smoking article may have a circular or near circular cross section, implying that any side or side portion of the smoking article may be placed against a substrate, such as when the smoking article is dropped on a surface or when the smoking article is left unattended.
• the patterns described herein define sides or side portions having film-forming compound not in contact with the substrate, regardless of the smoking article orientation when it happens to be in contact with the substrate.
• the smoking article may also have a non-circular cross-section.
• the wrapping paper and its zones of add-on material may include a plurality of discrete shapes, each of which extends over less than the length of the tobacco rod. At each of a plurality of spaced-apart longitudinal locations along the tobacco rod, only a first and second shape of the pattern is present in a cross section taken substantially perpendicular to the longitudinal axis of the tobacco rod. At one such location, the first shape is disposed only on a first side of the smoking article and the second shape is disposed only on a second side opposite the first side of the smoking article.
• the first and second shapes may be spaced apart by substantially 180° and have a porosity substantially less than the porosity of the base web. If desired, the plurality of discrete shapes may be arranged so that a cross-sectional plane through the tobacco rod intersects at least two such discrete shapes.
• FIG. 1 is a perspective view of a smoking article in accordance with a first embodiment of the invention.
• FIG. 2 is an enlarged plan view of an unwrapped portion of wrapping paper used in the construction of the smoking article of FIG. 1.
• FIG. 3 is an enlarged plan view of a wrapping paper for the smoking article illustrating a second quadrilateral pattern.
• FIG. 4 is an enlarged plan view of a wrapping paper for the smoking article, illustrating a third quadrilateral pattern.
• FIG. 5 is an enlarged plan view of a wrapping paper for the smoking article, illustrating a fourth quadrilateral pattern.
• FIG. 6 is an enlarged plan view of a wrapping paper for the smoking article, illustrating a triangular pattern.
• FIG. 7 is a side view of the smoking article using the wrapper paper of FIG. 3 with the smoking article on a substrate and oriented so that a first side portion of the smoking article contacts a substrate.
• FIG. 8 is a side view of the smoking using the wrapper paper of FIG. 3 with the smoking article on a substrate and oriented so that a second side portion of the smoking article contacts the substrate.
• FIG. 9 is a side view of the smoking article using the wrapper paper of FIG. 3 with the smoking article on the substrate and oriented so that a third side portion of the smoking article contacts the substrate.
• FIG. 10 is a cross-sectional view of the smoking article taken along line 10-10 of FIG. 7.
• FIG. 11 is a cross-sectional view of the smoking article taken along line 11-11 of FIG. 7.
• FIG. 12 is a cross-sectional view of the smoking article taken along line 12-12 of FIG. 7.
• FIG. 13 is an enlarged cross-sectional view of the smoking article positioned on a substrate and illustrating airflow to a smoldering coal.
• FIG. 14 is an enlarged cross-sectional view of the smoking article removed from the substrate and illustrating airflow to a smoldering coal.
• a first embodiment of a smoking article 20 (see FIG. 1 )
• FIG. 1 includes a tobacco rod 22.
• the tobacco rod 22 may include a cut filler of tobacco and is surrounded by wrapper paper 24.
• One end of the smoking article 20 may include a suitable filter 26 surrounded by suitable filter tipping paper 27.
• the smoking article 20 typically may have a generally circular cross section over the length of the smoking article. Nevertheless, other cross-sectional shapes including, for example, oval, are within the scope of this description.
• the tobacco rod 22 has a nominal length L measured from an edge of the tipping paper 27 to the free end of the tobacco rod 22 along a longitudinal axis A of smoking article 20.
• that nominal length may lie in the range of about 60mm to about 100mm.
• the wrapper paper 24 includes a base web which typically is permeable to air. Permeability of wrapper paper is typically identified in Coresta units. A Coresta unit measures paper permeability in terms of volumetric flow rate (i.e., cm 3 /sec) per unit area (i.e., cm 2 ) per unit pressure drop (i.e., cm of water).
• the base web of conventional wrapper paper also has well- known basis weights, measured in grams per square meter, abbreviated as "gsm”. The permeability and basis weight for the base web of typical smoking article papers commonly used in the industry are set out in the table below:
• the base web 24 of a preferred wrapper paper has a permeability of at least about 20 Coresta units. Most preferably, the wrapping paper has a permeability greater than about 30 Coresta, such as common base webs having nominal permeabilities of about 33 and about 46 Coresta with a basis weight of about 25 gsm. For some applications, the base web may have a permeability of greater than about 60 Coresta, or greater than about 80 Coresta, or even higher permeability values.
• the paper wrapper further comprises pairs of add-on material zones at spaced locations along the tobacco rod 22 in FIG. 1 (such as the opposing pair of zones 34d, 36d).
• Each pair of rectangular zones (for example, 34a and 36a-the latter not being visible in FIG. 1) define a circumferential region 31 (for example, the region 31a).
• the "width" of the banded region 31a is measured from a leading edge 7 of the region 31a (it being closest to an approaching coal) to the trailing edge 9 (it being most remote from an approaching coal).
• the width of the regions, e.g., 31a lies in the range of about 5.5mm to about 12mm, more preferably, about 7mm to about 10mm, and most preferably about 8mm to about 9mm.
• each zone 34a, 36a extends circumferentially (i.e., in cross-measure relative to the paper web) in the range of about 5mm to about 9mm in cross-measure, more preferably, about 6mm to about 7mm in cross-measure.
• width will extend in a longitudinal direction of the tobacco rod, whereas a dimension in the circumferential direction will be expressed as “transverse” or “cross-direction” or “cross-measure”.
• the area 33 of base web between adjacent regions 31a, 31b and the areas between opposing zones within each region are preferably essentially free of add-on material comprising the zones (e.g., zones 34b, 36b).
• the longitudinal distance between adjacent regions is referenced as band spacing 33, which is preferably about 4mm to about 12mm, and more preferably about 6mm to about 8mm.
• the respective opposing zones 34, 36 of each region 31 are offset from those of a preceding row or region to a degree (in accordance with teachings which follow) and a sufficient number of regions 31 are established along a given tobacco rod (per selection of band-region width and width of band-region spacing) that, when the smoking article is placed up on a substrate, that there occurs at least one location 101 along the tobacco rod 22 where the respective pair of zones 34 are oriented substantially alongside the tobacco rod 22, such as the opposing pair of zones 34b, 36b in FIG. 1. It is at or about this portion (location 101) of the tobacco rod 22 where self-extinguishment is most likely to occur.
• the location along the tobacco rod 22 where this orientation most closely occurs is hereinafter referenced as the "oriented snuffer region 101.”
• the smoking article 26 might be laid upon a substrate differently from that shown in FIG. 1 and/or because its pattern of zones may differ, it is to be realized that the oriented snuffer region 101 may appear at different longitudinal positions along the tobacco rod 22 for different rotational positions of the tobacco rod 22.
• the pattern of zones and the band spacing 33 may be selected such that more than one oriented snuffer region 101 may occur along the tobacco rod 22.
• each zone 34, 36 and 36' includes sufficient add-on material to reduce the permeability of the wrapper at each zone to 0.0 to about 10 CORESTA, more preferably about 7 Coresta or less.
• Ignition propensity is a standard test conducted as set forth in ASTM E 2187—04, "Standard Test Method for Measuring the Ignition Strength of Smoking articles", which is incorporated herein in its entirety by this reference thereto. Ignition propensity measures the probability that a smoking article, when placed on a substrate, will generate sufficient heat to maintain static burning of the tobacco rod 22. Low values for ignition propensity are desirable as such values correlate with a reduced likelihood that a smoldering smoking article will cause combustion in an underlying substrate.
• Self-extinguishment herein is a reference to smoldering characteristics of a smoking article under free-bum conditions.
• a laboratory test is conducted at a temperature of 23°C ⁇ 3°C and relative humidity of 55% ⁇ 5%, both of which should be monitored by a recording hygrothermograph. Exhaust hood(s) remove combustion products formed during testing.
• smoking articles to be tested are conditioned at 55% ⁇ 5% relative humidity and 23°C + 3°C for 24 hours.
• the smoking articles are placed in glass beakers to assure free air access.
• Self-extinguishment testing takes place within an enclosure or test box.
• a single port smoking machine or an electric lighter is used to ignite the smoking articles for the test.
• an apparatus or "angle holder” holds the smoking articles to be tested by holding an end at angles of 0 degrees (horizontal), 45 degrees, and/or 90 degrees (vertical). Twenty (20) smoking articles are tested at each of the 0 degrees, 45 degrees, and 90 degrees positions. If more than one apparatus is used, the apparatuses are preferably positioned such that the smoking articles face away from each other to avoid cross interference.
• a smoking article goes out before the front line of the smoldering coal reaches the tipping paper, the outcome is scored as "self-extinguishment”; on the other hand, if the smoking article continues smoldering until the front line of the smoldering coal reaches the tipping paper, then the outcome is scored as "non-extinguishment".
• a self-extinguishment value of 95% indicates that 95% of the smoking articles tested exhibited self-extinguishment under free-bum conditions; while a self-extinguishment value of 20% indicates that only 20% of the smoking articles tested exhibited self-extinguishment under free-burn conditions.
• the self-extinguishment value may be referred to in terms of "self-extinguishment at 0 degrees value”, “self-extinguishment at 45 degrees value”, or “self-extinguishment at 90 degrees value”, each of which refers to the value of self-extinguishment at the specified tested angle.
• the self-extinguishment value may be referred to in terms of "self-extinguishment Average value”, which refers to an average of the three angular positions: namely, an average of (i) the "self-extinguishment at 0 degrees value", (ii) the "self-extinguishment at 45 degrees value", and (iii) the "self-extinguishment at 90 degrees value”.
• the staggered zones of add-on material permit a smoking article 20 (see FIG. 1) to be designed with an advantageous combination of low ignition propensity values and low self-extinguishment values.
• the patterns of low permeability zones of add-on material provide areas of film-forming compound along the length of the tobacco rod 22 that can cooperate with a substrate to extinguish the lit smoking article 20 when it is placed on that substrate, yet these areas of add-on material (such as a film- forming compound) cause the smoking article 20 to self-extinguish at statistically fewer occurrences when the smoking article 20 is held by a smoker in a free-burn condition.
• the smoking article 20 can exhibit a reduced ignition proclivity while retaining a desirable free-burn quality or low self-extinguishment value by applying a pattern 30 of film-forming compound to the base web according to this description.
• a pattern 30 is applied to the base web 24 of the wrapper paper, preferably while the base web 24 is in an unfolded condition, such as shown in FIG. 2, or when the base web comprises a roll of cigarette paper that has yet to be slit into bobbins.
• An object of this description is to provide wrapper papers which, when formed into a tobacco rod 22, exhibit IP values no greater than 25 and self-extinguishment values no greater than 50. Even more preferred, is an IP value for the resulting smoking article no greater than about 15; and the most preferred IP value for the resulting smoking article is no greater than about 10. Lower self- extinguishment values are also desired. In this connection, a more preferred self- extinguishment value is less than about 25; while the most preferred self-extinguishment value is less than about 10.
• the transverse dimensions of the wrapper paper 24 are selected based on the diameter of the finished smoking article (about 7mm to about 10mm) and allowing for overlapping material at a longitudinal seam of about 1mm to about 2 mm.
• the wrapper-paper cross-web dimension may be about 27mm for a smoking article having a circumference of about 25.6mm.
• the pattern is applied to the base web such that a plurality of circumferentially extending regions 31a, 31b, 31c, 31 d (defined by broken lines in FIG. 2) are disposed at spaced locations along the tobacco rod 22 (see arrow B, in FIG. 2).
• the add-on material can be applied to one or to both sides of the base web.
• three to six, and most preferably four to six or more, of the regions 31 occur in the nominal length of the tobacco rod 22.
• Each of the circumferential regions 31a, 31b, 31c, 31 d has a longitudinal pitch along the tobacco rod 22 ⁇ i.e., length measured along the tobacco rod from the beginning of one region to the beginning of the adjacent region) which is less than the nominal length of the tobacco rod 22. By selecting the longitudinal pitch length at about 25% of the nominal length, four regions will be provided on each tobacco rod 22.
• each circumferential region e.g., 31a
• at least two zones, e.g., 34a, 36a, of addon material are provided.
• the zones of add-on material in all of the Figures are identified with stippling to aid identification of them; however, in a smoking article or wrapper paper for such a smoking article, these zones of add-on material may, or may not, be visually identifiable.
• Each of these zones is preferably spaced circumferentially such that the zones will be opposed to one another in the finished tobacco rod 22.
• the zones 34b, 36b of the second region 31b preferably are circumferentially offset from the zones 34a, 36a of the first region.
• the zones 34c, 36c of the third region 31c preferably are circumferentially offset from the zones 34b, 36b of the second region 31b, and even further offset circumferentially form the zones 34a, 36a of the first region 31a.
• the add-on zones of each region in this embodiment are laterally offset in a circumferential direction from the add-on zones of an adjacent region by a distance that is a function of the transverse dimension of the add-on zones.
• Each zone has a width measured along the tobacco rod 22 and a transverse cross-measure dimension in the circumferential sense of direction of the tobacco rod 22.
• the zone width is less than the longitudinal pitch of the associated region.
• the longitudinal pitch length may be greater than the corresponding zone width of the corresponding region.
• the add-on zones of successive regions along the tobacco rod 22 are preferably offset from the add-on zones of the adjacent regions, thereby defining a pattern 30 of regions which cover portions of the base web along lines inclined relative to the edge of the base web. Furthermore, the pattern of addon zones may repeat itself at least partially along the length of the base web.
• each zone is placed on the wrapper paper 24 so that the zone is centered upon one of three paths 34, 36, and 38, which paths are represented by corresponding broken lines 34, 36 and 38.
• path 34 passes through the corresponding geometric features of six zones 34a, 34b, 34c, 34d, 34e, 34f.
• Each zone is spaced from the other zones, but the zones could, alternatively, contact one another.
• the paths 34, 36 and 38 are parallel to each other and oriented at an acute angle ⁇ relative to the side edge of the wrapper paper 24. It is to be realized that zones 36' are preferably the same as zones 36 and result from progression through the pattern shown in FIG. 2 where, as zones 34 disappear along one edge, zones 34' appear along the opposite edge.
• Each pair of cross-web aligned zones may cover up to about 33% of the total surface area of the corresponding region 31a, 31b.
• each zone is preferably in the range of about 8mm to about 10mm in the longitudinal direction or width, and about 5mm to about 7mm in the circumferential cross-measure direction.
• Longitudinal spacing 33 between the zones preferably lies in the range of 4mm to about 12mm, and more preferably in the range of about 6 to about 8 mm.
• the circumferential spacing of the zones of add-on material is preferably in the range of about 3mm to about 20mm, more preferably in the range of about 5mm to about 8mm, and most preferably in the range of about 5.5mm to about 7.0mm.
• zones of add-on material at any longitudinal location are preferably spaced about 180 degrees from each other.
• the ratio of the area occupied by zones of add-on material to the total area is substantially less than one.
• zone area ratio lies in the range of less than about 20% to less than about 50%, and more preferably in the range of less than about 20% to less than about 35%. More particularly, in some embodiments the zone area ratio for zone-occupied area to total area may be less than 30%, and even less that 25%. Generally speaking, it is desirable to keep the zone area coverage ratio low because high values (i.e., closer to 1) are believed to increase carbon monoxide concentration in mainstream smoke where low permeability (i.e., low Coresta) wrapper paper is used for the tobacco rod.
• the paths 34, 36, 36' describe a first helical path 36/36' (zones 36 and 36' in FIG. 2 combine to form a helical path 36/36') and a second helical path 34 (comprising helically aligned zones 34) both of which extend lengthwise, around axis A, and over the length of the tobacco rod 22, as illustrated in FIGS. 7-9.
• the helical paths 36/36' and 34 (as seen from FIG. 2) have a helix angle ⁇ and do not intersect one another.
• both helical paths may follow one of a counterclockwise and clockwise rotation about the tobacco rod 22.
• both paths 34, 36' follow a clockwise path, starting at the filter end of the tobacco rod 22, when viewed from the lit end and looking towards the filter end.
• the zones of the pattern 30 may be formed by applying one or more layers of an aqueous film-forming composition to the base web of the wrapper paper to reduce the permeability of the paper in those zones.
• a cellulosic material may also be used to form the zones.
• a film-forming composition preferably may include water and a high concentration of an occluding agent, e.g., 20% to about 50% by weight.
• the film-forming compound can include one or more occluding agents such as starch, alginate, cellulose or gum and may also include calcium carbonate as a filler. Where starch is the film-forming compound, a concentration of about 24% may be advantageous.
• the film-forming composition may be applied to the base web of the wrapper paper 24 using gravure printing, digital printing, coating or spraying using a template, or any other suitable technique.
• the film-forming compounds and methods for applying film-forming compounds described in US patent application number 11/500,918, which is hereby incorporated herein in its entirety by this reference thereto may be chosen for applying a pattern to the base web of the wrapper paper.
• the zones of add-on material can be formed by printing multiple, successive layers, e.g., two or more successive layers registered or aligned with one another.
• the material in layers may be the same of different. For example, one layer may be starch while the next layer may be starch and calcium carbonate (or vice versa).
• each zone 40a, 40b is preferably selected to be less than about 50% of the cross-measure of the base web 24 when unwrapped, and most preferably about 25% of the cross-measure of that base web 24 or of the circumference of the tobacco rod 22.
• the circumferential dimension of each zone 40a, 40b, when added to the circumferential spacing of between the zones 40a, 40b, preferably is about 50% of the circumferential cross-measure of the base web 24.
• the longitudinal length of the zones 40a, 40b plus the longitudinal spacing 33 between the zones 40a, 40b, and zones 42a, 42b, is preferably selected so that three or four regions 31a, 31b, 31c, 31 d will occur in the nominal length of the tobacco rod 22 of the smoking article and such that add-on zones of adjacent regions are spaced from one another longitudinally.
• the longitudinal expanse or "width" of the zones, e.g., 40a, 40b i.e., the zone width or region width as previously defined lies in the range of about 8mm to about 10mm.
• the circumferential offset, x, between (i) the zones 42a, 42b of the region 31b and (ii) the zones 40a, 40b of the region 31a preferably lies in the range of about 10% to about 35% of the total, unwrapped cross-measure of the base web 24. More preferably, the circumferential offset, x, lies in the range of about 12% to about 35% of the total, unwrapped cross-measure of the base web 24. Most preferably, the circumferential offset, x, is about half the circumferential dimension or cross-measure of the add-on zone 40a, 40b.
• the zones of add-on material in other regions, 31c, 31 d, are likewise further offset circumferentially by the same offset, x, with respect to each other. It will be noted that, for example, in region 31 d one of the zones 46a, 46c of add-on material gets split between the two edge portions of the base web 24 when the base web is in an unwrapped condition.
• the pattern applied in regions 31a-31d preferably repeats along the length of the base web 24.
• the circumferential offset, x is less than 12.5% of the cross-directional width of the base web, more than four regions will define a complete cycle or phase length for the pattern 30.
• the circumferential offset, x is greater than 12.5%, less than four regions will define a complete cycle length for the pattern 30 (as in the case of the FIG. 2 pattern).
• a further embodiment of the pattern 30 uses quadrilateral zones 60a, 60b of addon material, namely substantially parallelogram-shaped zones. While the zones 60a, 62a are arranged so as to be in general helical alignment with one another when the wrapper paper is formed into a tobacco rod 22, the configuration of the parallelogram shapes 60, 62, 64, 66 may be selected as desired. For example, the mirror images of the shapes (mirrored about the longitudinal direction) could be used, even though the general helical impression might be lost. Likewise, the skewness of the parallelogram zones may be changed as may be desired. Generally, however, the circumferential dimensions, circumferential spacing or offset, longitudinal dimensions, and longitudinal spacing or offset of the zones 60, 62, 64, 66 and the regions 31a-31d in this embodiment may be selected as described in other embodiments.
• Still another embodiment of the pattern 30 uses quadrilateral zones 70, 72, 74, 76 of add-on material, namely substantially trapezoidal zones.
• the generally trapezoidal zones 70a, 72a may be arranged so as to be in general helical alignment with one another when the wrapper paper is combined into a tobacco rod 22.
• the actual shape of the trapezoidal zones 70, 72, 74, 76 may be selected as desired. For example, the skewness of the trapezoidal zones, and the proportions of the trapezoidal zones may be changed as may be - desired.
• the circumferential dimensions, circumferential spacing or offset, longitudinal dimensions, and longitudinal spacing or offset of the zones 70, 72, 74, 76 and the regions 31a-31d in this embodiment may be selected as described in other embodiments. It is preferred that the leading edge 7 be the longer of the two parallel edges of the zones 70.
• Yet another embodiment of the pattern 30 uses generally triangular zones 80, 82, 84, 86 of add-on material.
• the generally triangular zones 80a, 80b of region 31a may be constructed and arranged so as to touch the corresponding generally triangular zones 82a, 82b of the next adjacent region 31b.
• the generally triangular zones 80a, 80b of the first region 31a may be longitudinally spaced from the triangular zones 82a, 82b of the adjacent region 31b.
• the generally triangular regions may be oriented so that the burning coal of a smoldering smoking article encounters the triangular apex and gradually increasing cross-directional dimension of the generally triangular zones (i.e., from right-to-left in FIG. 6), or such that the burning coal of a smoldering smoking article encounters the base of the triangular zones and an abrupt increase in the lower permeability zones (i.e., from left-to-right in FIG 6).
• Circumferential spacing of the triangular zones 80, 82, 84, 86 and the size of those triangular zones may be determined in accordance with the preferred ranges set out elsewhere in this description.
• the triangular zones may be isosceles triangles as depicted, or equilateral triangles, or right triangles, or any other desired triangular shape that may be desired.
• the circumferential dimensions, circumferential spacing or offset, longitudinal dimensions, and longitudinal spacing or offset of the zones 80, 82, 84, 86 and the regions 31a-31d in this embodiment may be selected as described in other embodiments.
• the triangular forms of the zones 80 are oriented so that a leading edge 4 (closest to an approaching coal) is established.
• FIG. 7 illustrates a side view of the smoking article 20 according to this description. Rotation of the smoking article through a 45 degree angle about its longitudinal axis (clockwise from the left end of FIG. 7) results in an elevation similar to that shown in FIG. 8. Similarly, further rotation of the smoking article 20 through another 45 degree angle (also clockwise from the left end of FIG. 7) results in an elevation to that illustrated in FIG. 9. In each of FIGs.
• the zones 92, 92' are substantially upright or generally perpendicular to the surface of the substrate 98. That orientation of the zones 92, 92' is best illustrated in FIG.
• FIGs. 10 and 11 Orientation of the zones of add-on material at other longitudinal locations along the smoking article 20 are shown in FIGs. 10 and 11.
• the zones 90, 90' of add-on material are positioned such that one zone 90 touches the substrate 98.
• the zones 94, 94' of the smoking article 20 in FIG. 7 would also be positioned as in FIG. 10, when viewed from the right end of FIG. 7.
• one zone 96' contacts the substrate 98, but the other opposed zone 96 is located at the top of the smoking article 20.
• the zones 92, 92' obstruct airflow to the burning coal of the tobacco rod 22 by virtue of their reduced permeability.
• the bottom portion 104 of the wrapper paper freely permits air to enter the side of the tobacco rod 22 to support combustion of the coal.
• a vastly different situation occurs when the smoking article 20 is placed on a substrate 98 (see FIG. 13).
• the substrate 98 blocks the flow of air upwardly to the bottom portion 90 of the tobacco rod 22.
• the zones 92, 92' and the substrate 98 cooperate to define much smaller areas 100, 102 through which air can be delivered through the base web.
• the vertical area 100 between the bottom of the zone 92 and the substrate 98 and the vertical area 102 between the bottom of the zone 92' and the substrate 98 present a substantial reduction in the area through which air can pass to reach the smoldering coal of the tobacco rod 22.
• the smoldering coal self-extinguishes when the burn line reaches opposed zones of add-on material positioned as depicted in FIG. 13.
• the condition of substantially reduced area for air to support burning of the coal also exists for rotational positions of the tobacco rod 22 between that position illustrated in FIG. 10 and the position illustrated in FIG. 12 when the zones of add-on material do not contact the substrate 98, with FIG.
• the add-on zones may sufficiently restrict the area through which air can pass to the base web, and there is a lesser degree of material cooperation between the substrate 98 and the add-on zones to effect a reduction in that area, in comparison to what occurs at the snuffer zone(s) 101.
• the reduction in ignition propensity value, reduction in self- extinguishment value, and improved free-burn quality of a smoking article 20 having a wrapping paper with pattern 30 formed thereon is discussed in relation to a situation where the smoking article happens to be placed on a substrate 98 at one of three specific orientations, the orientations being spaced (off-set) 45 degrees apart from each other.
• the discussion proceeded in this manner for the sake of brevity. It will be readily understood that a pattern according to this description can extinguish the smoking article, regardless of which side portion rests against a substrate 98 and without a need for applying film-forming compound to the paper to such an extent that a desirable free-bum quality in the smoking article is lost.
• opposing zones of film-forming compound need not appear at locations exactly 90 degrees from the side portion in contact with the substrate 98. Those zones may be centered at a location that is closer to or farther from the side portion in contact with the substrate 98, for example, between about 60 degrees and 120 degrees from the side portion in contact with the substrate 98.
• the ability to extinguish the smoking article may depend more on providing minimum lengthwise extent of add-on material (e.g., a film- forming compound), rather than a particular weight per area of film-forming compound at longitudinal locations.
• add-on material e.g., a film- forming compound
• the length of a rectangular zone may be no less than about 5.5mm for a particular design, base web, and film-forming compound used.
• the amount of film-forming compound used may be increased to improve ignition propensity performance, usually without losing a free-burn quality, and if desired, a burn accelerator may be applied to the paper to support even higher add-on levels.
• the zones of add-on material reduce permeability of the wrapper paper to the range of from about 0 to about 10 Coresta.
• a permeability ratio of 3:1 between the base web and zones of add-on material was insufficient to extinguish the smoking article because there is an insufficient reduction in the permeability of the paper at the longitudinal location.
• that permeability ratio over a portion of the circumference of the smoking article, can be sufficient to extinguish the smoking article when the add-on material is located at sides of the smoking article not in contact with the substrate 98 and when there is an underlying substrate 98.
• the spirally rotated position of the opposed zones of add-on material creates a situation where, regardless of which side portion of the wrapper paper is placed against the substrate 98, there will always be at least one longitudinal location having film-forming compound at side portions not in contact with the substrate 98 yet having a sufficient add-on amount and geometry that the zones can cooperate with the substrate 98 to self-extinguish the smoking article when the burn line reaches that longitudinal location.
• This fact results in improved ignition propensity performance of the smoking article and permits a smoking article to be designed with an ignition propensity value no greater than 25%.
• the smoking article does not self-extinguish yet maintains a free-bum, such as when the smoking article is held by a smoker.
• This fact results in improved self-extinguishment performance of the smoking article and permits a smoking article to be designed with an self-extinguishment value no greater than 50%, that self-extinguishment value may be the self-extinguishment average value, self-extinguishment values at 0 degrees may be much lower that the SE average value and may be less than 25%.
• the smoking article has a generally circular cross section. Therefore, it is possible for any side portion of the smoking article to rest against the substrate 98.
• a pattern as taught herein can be such that the burn characteristics described above (ignition propensity values no greater than 25% and E values no greater than 50%) in relation to FIGS. 13 and 14 can be realized, regardless of which side portion of the smoking article happens to rest against the substrate 98.
• the pattern is selected so that when the base web is wrapped around a tobacco rod 22, zones of film-forming compound appear at opposing sides not in contact with the substrate 98 at one or more longitudinal locations along the tobacco rod 22.
• the zones of add-on material may also comprise other geometric shapes other than quadrilaterals including, for example, ovals, other polygons, or the like.
• helix angle ⁇ described above may be increased while keeping the dimensions of zones the same as in the illustrated embodiments. That change can place the zones in an overlapping pattern (or at least place zones in close proximity to one another).
• a stepped helical pattern may be formed by increasing the cross-directional dimension of the zones or patches while the helix angle is the same as in FIG. 2 and/or a zone of equal size to that shown in FIG. 2 may be placed between each patch and along paths 34, 36, 36' (so that there are 12, instead of 6 patches along a path 34).

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