REDUCED IGNITION PROPENSITY CIGARETTES AND METHODS FOR THEIR MANUFACTURE

REDUCED IGNITION PROPENSITY CIGARETTES AND METHODS FOR

THEIR MANUFACTURE

FIELD OF THE INVENTION

This invention relates to reduced ignition propensity cigarettes. In particular, the invention relates to cigarettes containing burn retardant zones, as well as to methods for manufacturing such a cigarette.

BACKGROUND TO THE INVENTION

A cigarette is broadly defined as a roll of tobacco capable of being smoked as it is and which is not a cigar or cigarillo; a roll of tobacco which, by simple non-industrial handling, is inserted into a cigarette-paper tube; or a roll of tobacco which, by simple non-industrial handling, is wrapped in cigarette paper. Cigarettes. and methods for their manufacture are widely known.

A problem currently experienced with most conventional cigarettes is that they are not self-extinguishing. In other words, once lit, most cigarettes can continue burning through their entire length without having to be actively smoked. This self sustained burning is generally obtained by impregnating the cigarette paper surrounding the tobacco roll with a burn accelerant such as sodium citrate. While the self-sustained burning alleviates the need for smokers to constantly re-light their cigarettes, as well as increase cigarette consumption, it also creates a substantial fire hazard if burning cigarettes are left unattended. In essence, the length of time a cigarette bums after having been left unattended is directly proportionate to the amount of fire risk it poses. It is generally only when unattended, burning cigarettes are left in contact with a combustible fuel for some time that they pose a risk of fire. It is therefore extremely desirable to reduce the amount of time an unattended, burning cigarette is allowed to burn. There has also been considerable pressure on cigarette manufacturers to reduce the levels of smoke and harmful chemicals that are being emitted into the atmosphere as a result of cigarette smoke. The smoke from burning cigarettes not only adds to pollution levels, but is also harmful to non- smokers who are in the vicinity of burning cigarettes (this is commonly referred to as passive smoking). Passive smoking is understood to be the inhalation of smoke, called second hand smoke (SHS) or environmental tobacco smoke (ETS), from tobacco products used by smokers.

One way of reducing the amount of passive smoke in the atmosphere is to reduce the burning propensity of conventional cigarettes. It has, however, been found that simply removing the burn accelerant from the smoking paper is not the most desirable way of achieving this. In addition, known methods of creating reduced ignition propensity cigarettes have been found to be ineffective in windy conditions.

United States patent number 4,483,349 entitled "Filter Cigarette Making Machine" in the name of Molins Limited ("Molins") discloses a cigarette filter attachment machine which includes a fluted drum which is arranged to receive double filters and double tobacco rods. A knife cuts the double tobacco rods through the middle to form separate tobacco rod portions and, with the aid of a further drum, the two portions associated with each double filter are swopped in position so as to lie at opposite ends of the double filter, displacement of one of the tobacco rod portions being achieved preferably by displacing the associated double filter which in turn pushes the tobacco rod portion. The double tobacco rods may be delivered axially into the flutes of the first drum from a cigarette making machine, preferably after delivery of the double filters which can then serve as resilient buffers for the incoming double tobacco rods. The machine disclosed in Molins has been used extensively in cigarette production and, to the applicant's knowledge, is still being used today. It should be appreciated that the machine produces filtered cigarettes from double tobacco rods so that, after the double tobacco rods have been cut into cigarette portions and the filters attached, the cut ends are positioned at the non-filtered ends thus providing cigarettes with neatly cut ends. The machine also provides a way of swopping the positions of two separate filtered cigarettes or cigarette portions that are positions end- to-end.

Machines capable of performing the functions of Molins and for making cigarettes in general are, however, expensive. It can therefore be assumed that machines capable of manufacturing cigarettes in accordance with the current invention will likewise be very expensive to manufacture from scratch. If reduced ignition propensity cigarettes in accordance with the current invention are therefore to be manufactured it would be beneficial if currently available machines could be inexpensively adapted for this purpose.

There is accordingly a need for reduced ignition propensity cigarettes and ways Of economically manufacturing them.

In the remainder of this specification the term "tobacco roll" will refer to a roll of tobacco of an undefined length. A "cigarette rod", in turn, will refer to a tobacco roll which is wrapped in smoking paper.

OBJECT OF THE INVENTION

It is an object of this invention to provide a reduced ignition propensity cigarette as well as a method of manufacturing it which will, at least partially, alleviate the abovementioned problems.

SUMMARY OF THE JNVENTION

In accordance with this invention there is provided a reduced ignition propensity cigarette comprising a paper body containing a tobacco roll, the cigarette being characterized in that a zone exists in the tobacco roll intermediate its ends through which tobacco strands do not pass but are generally in abutment, and in that a bum retarding band extends at least partially about the zone.

A further feature of the invention provides for the tobacco roll to be at least partially severed in a direction substantially transverse to its major axis intermediate its ends to form the zone, thus yielding two tobacco sections positioned in end-to-end abutment, alternatively, for it to be completely severed in a direction substantially transverse to its major axis intermediate its ends to form a zone with no tobacco strands passing therethrough.

Still further features of the invention provide for the tobacco roll to include more than one zone and a burn retarding band extending at least partially about each such zone; for the tobacco roll to be at least partially severed in a direction substantially transverse to its major axis intermediate its ends to form each- zone, thus yielding, more than two tobacco sections positioned in end-to-end abutment; for the cigarette to have a filter attached co-axially with the body at an end thereof, alternatively for it to include two filters attached co-axially with the body, one at each end thereof; and for the burn retardant band to comprise a band of smoking paper which is substantially free of burn accelerant.

Yet further features of the invention provide for the reduced ignition propensity cigarette to comprise two abutting, co-axially aligned separate cigarette rod sections joined end-to-end by means of a burn retardant band; for the burn retardant band to be a strip of smoking paper; for the strip of smoking paper to be substantially free of burn accelerant extending at least partially about the joined ends of the cigarette rod sections; for the cigarette to include at least one additional bum retardant band extending at least partially about a cigarette rod section intermediate its ends; for each cigarette rod section to comprise a cylindrical paper body containing a tobacco roll with a zone existing in each tobacco roll intermediate its ends through which tobacco strands do not pass but are generally in abutment with a burn retarding band extending at least partially about each zone; and for the zone to be created by conventional cutting, laser cutting or the like.

The invention further provides a method of manufacturing a reduced ignition propensity cigarette comprising the steps of

(a) creating a zone in a tobacco roll intermediate its ends through which tobacco strands do not pass but are generally in abutment;

(b) wrapping the tobacco roll in a piece of smoking paper to form a cigarette rod, and

(c) wrapping a bum retardant band at least partially about the cigarette rod so that it extends at least partially about the zone.

Further features of the invention provide for. the order of steps (b) and (c) to be reversible; and for steps (b) and (c) to be performed together by laying down a burn retardant band on the piece of smoking paper and then wrapping the smoking paper about the tobacco roll so that the burn retardant band extends at least partly about the zone.

Still further features of the invention provide for step (a) to further comprise the step of at least partially severing the tobacco roll in a direction substantially transverse to its major axis intermediate its ends; for step (a) to comprise the step of completely severing the tobacco roll to form at least two separate tobacco sections and to further comprise the additional step of co- axially aligning the tobacco sections and positioning them in end-to-end abutment so as to form the zone; and for step (a) to further comprise creating more than one zone in the tobacco roll and step (c) to further comprise wrapping burn retardant bands at least partially about the cigarette rod so as to extend at least partially about each zone. The invention still further provides a method of manufacturing a reduced ignition propensity cigarette comprising the steps of aligning two or more cigarette rod sections end-to-end to form a zone between them through which tobacco strands do not pass but are generally in abutment and joining the aligned ends of the cigarette portions with a burn retardant band.

Further features of the invention provide for the step of joining the aligned ends of the cigarette rod sections to include joining them by means of a strip of smoking paper which is substantially free of burn accelerant and for the method to include wrapping at least one additional burn retardant band about the cigarette rod section intermediate its ends.

The invention yet further provides a method of manufacturing a reduced ignition propensity cigarette comprising the steps of cutting a double length cigarette rod into two cigarette rod sections; swopping the positions of the cigarette rod sections soJhat they are-co-axially aligned with their cut ends directed away from each other; inserting a double length filter between the swopped cigarette rod sections; wrapping the double length filter and the ends of the cigarette rod sections adjacent the double length filter with tipping paper to create a double filtered double cigarette; and cutting the double filtered double cigarette midway along the double length filter to form two filtered cigarettes; the method being characterized in that it includes the steps of swopping the positions of the filtered cigarettes so that they are co-axially aligned with their non-filtered ends adjacent one another and joining the adjacent non-filtered ends of the filtered cigarettes with a burn retarding band.

Further feature of the invention provide for the method to include the step of creating a line of weakness across the burn retarding band so that, after joining the adjacent non-filtered ends of the filtered cigarettes, the line of weakness is aligned with the joined non-filtered ends, thereby allowing the cigarette to be broken into two, individually smokable cigarettes; and the step of wrapping at least one additional burn retarding band about the cigarette rod, intermediate its ends.

The invention also provides a cigarette the tip of which has a high ignition propensity to facilitate ignition thereof.

Further features of the invention provide for the remainder of the cigarette to be treated to have a low ignition propensity; for the tip to have a strip of smoking paper extending thereabout treated to have a high ignition propensity; and for the strip of smoking paper to form part of a paper joining two cigarettes end to end in a breakable fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only with reference to the .accompanying-representations in -which:

Figure 1 is a reduced ignition propensity cigarette in accordance with an embodiment of the invention including a burn retardant band;

Figure 2 is a tobacco roll used in the reduced ignition propensity cigarette of Figure 1 ;

Figure 3 is a reduced ignition propensity cigarette in accordance with a further embodiment of the invention including multiple tobacco sections and burn retardant bands;

Figure 4 is a sequence illustrating the manufacture of the reduced ignition propensity cigarette of Figure 8 in accordance with a method of the invention; Figure 5 is a reduced ignition propensity cigarette in accordance with a still further embodiment of the invention; and

Figure 6 illustrates the sequence of events occurring during the manufacture of the cigarette of Figure 5 in accordance with an alternative method of the invention.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In the embodiment of the invention shown in Figures 1 and 2, a reduced ignition propensity cigarette (2) comprises a paper body (4) containing a tobacco roll (6).

The tobacco roil will generally have been cut from a longer, continuous roll that comprises numerous tobacco strands rolled together into a roll with the strands interweavingjn- substantially all directions. For the purpose of the current invention it should be appreciated at the outset that a substantial portion of the strands also extend in a direction generally along the major axis of the roll.

The tobacco roll (6) includes a zone (8) intermediate its ends (10), through which substantially no tobacco strands pass. The strands are, however, in abutment on either side of the zone (8). In this embodiment of the invention, the zone (8) extends substantially transverse to the major axis (12) of the cigarette (2) thus yielding two sections (14, 16) of tobacco positioned in end - to - end abutment. A burn retardant band (18) extends around the cigarette (2) and over the zone (8). The burn retardant band (18) is a strip of smoking paper which is substantially free of burn accelerant.

If the cigarette (2) is lit by a smoker and left unattended, the cigarette and tobacco will burn along the length of the cigarette towards the filter. This is mainly due the burn accelerant present in the smoking paper. When the burn reaches the burn retardant band (18) it will be retarded, the burn accelerant in the smoking paper (4) underneath the band (18) in combination with the smouldering tobacco strands may, however, still promote burn, albeit slower, towards the filter. When, however, the burn reaches the zone (8), the combination of the burn retarding band (18) and zone (8) will prevent the cigarette from burning past the zone (8). It should be appreciated that the lack of tobacco strands passing through the zone (8) implies that smouldering strands will die out at the zone (8).

It should be appreciated that tobacco contracts as and when it burns. This is clearly evident when watching cigarette ash as it forms on the cigarette. The ash section that forms as the cigarette burns is always shorter and thinner than the cigarette rod prior to burning. As the tobacco burns towards the zone, the tobacco strands on the burning side of the cigarette contract, thereby essentially enlarging the zone, making it increasingly harder for the cigarette-to continue-buming .across the retardantzone without assistance.

If, however, a smoker draws on the cigarette as the burn approaches the zone (8), the additional heat and air flow through the cigarette (2) will result in the tobacco burning across the zone (8), thus resulting in a continuous smoke.

The zone (8) in the tobacco roll (6) may only be a partial cut through it. Such a partial cut may in some cases be sufficient to prevent burning across the zone (8) and the cigarette (2) will extinguish at the zone (8) if not smoked.

A second embodiment of a reduced ignition propensity cigarette (30) is shown in Figure 3, in this embodiment, the cigarette (30) includes a cigarette rod (32) (a cylindrical paper body containing a tobacco roll) and one cigarette filter (34) connected co-axially with the rod (32) at an end (36) thereof. The cigarette rod has three separate sections (38), abutting end-to-end in two zones (40) between the ends (36) of the cigarette (30). A burn retardant band (42), in the form of a strip of smoking paper which is substantially free of burn accelerant, is wrapped around each pair of abutting ends of the cigarette rod sections (38) to join them together.

The cigarette (30) may therefore be smoked all the way through if a smoker continually draws on it, particularly when the burn reaches the zones (40), or may be left alone in which case it will self-extinguish at the next zone (40).

Steps involved in a method of manufacturing a reduced ignition propensity cigarette as shown in Figure 3 are illustrated in Figure 4. It should be appreciated that even thought the cigarette of Figure 3 is shown without a filter in Figure 4, filters may be added to the cigarette shown by conventional methods at one or both ends of the cigarette. A cigarette rod (60) is shown at a stage (A). At stage (B), the cigarette rod (60) is cut into three separate cigarette rod sections (62) at two cut lines (64). After cutting, the cigarette rod sections (62). are_positioned in end=to-end abutment, each pair of ends (66) abutting in a zone (68) as shown at stage (C). Two burn retardant bands (70) in the form of strips of smoking paper that are substantially free of burn accelerant are then wrapped about the abutting ends (66) at stage (D), thereby joining the cut cigarette rod sections (62) together again. The reduced ignition propensity cigarette (72) thus formed is shown at stage (E). If lit at one of its ends and left unattended, the cigarette (72) will again self- extinguish when it reaches one of the zones (68).

As before, it should be appreciated that the cutting of the cigarette rod could be achieved by any standard means such as by means of a blade or laser. It is also foreseeable that the cut may be achieved by means of a pulsing laser after the tobacco roll has been wrapped in the paper body, in which case the zone will not be continuous, but will be a series of spaces apart linear zones. In the latter case the tobacco would be at least partly cut although some tobacco strands may still span between the cigarette rod sections. It should also be appreciated that there is no limit to the number of cuts that can be made through the cigarette rod and that any number of cigarette rod sections may subsequently be rebound, thus allowing for a reduced ignition propensity cigarette having any number of extinguishing zones. The cuts through the cigarette rod may also be made only partly therethrough. In which case the tobacco strands will be completely severed in a portion of the rod and spanning between the sections in another portion. Such a partial cut, while still resulting in self-extinguishing of the cigarette, may allow for greater rigidity of the cigarette and may also ensure a more uniform dropping of burnt cigarette ash.

A still further embodiment of a reduced ignition propensity cigarette (80) in accordance with the invention is shown in Figure 5. A method of manufacturing the cigarette in accordance with this embodiment will now be described with reference to Figure 6, which illustrates the sequence of events occurring during the manufacture of the cigarette. The applicant's co- pending_patentapplication describes_a-breakable cigarette and a method of manufacturing a breakable cigarette. For the sake of convenience the method will be repeated here and adapted to show how a reduced ignition propensity cigarette in accordance with this embodiment of the invention can be produced by a similar method.

At stage (A), a double length cigarette rod (82) is cut into two separate cigarette rod sections (84) by means of a cutting mechanism (not shown) along a cutting line (86). The positions of the cigarette rod sections (84) are then swopped at a stage (B), so that they are again aligned co-axially with their cut ends (88) directed away from each other. The tobacco rod portions are then separated at a stage (C) and a double length filter rod (90) is inserted between the cigarette rod sections (84). At this stage, the cigarette rod sections (84) and double filter rod (90) should be next to each other with little or no gaps between the various parts. The double filter rod (90) and the ends of the cigarette rod sections next to it are then wrapped with tipping paper (92) at a stage (D) so as to join the double filter and the ends of the cigarette rod sections together. As is common practice in the industry, glue is applied to at least one end region of the tipping paper before the tipping paper is wrapped around the double filter and ends of the cigarette rod sections and glued back onto itself. The cigarette rod section/double filter/cigarette rod section combination at this stage forms a double filtered double cigarette (94). The double filtered double cigarette (94) is then cut into two separate, filtered cigarettes (96) at a stage (E). Up to this stage, the method for manufacturing the reduced ignition propensity cigarette of Figure 5 corresponds to that disclosed in the prior art and, in particular, in Molins' patent referred to in the background section of this specification. The distinguishing features of the current invention are embodied in steps F and G, as described below.

At a stage (F), the-positions of the two. separate, filtered cigarettes (96) are again swopped around so that they are again co-axially aligned but this time with their non-filtered ends (98) adjacent one another. This may be done by any of the conventional methods known for swapping ends. A zone (102) is thereby defined between the cigarettes (96) through which no tobacco strands pass, but at which they abut on either side. The filtered cigarettes (96) are then joined to one another at stage (G) by wrapping a burn retardant band (100) comprising a strip of smoking paper which is substantially free of burn accelerant around the adjacent, non-filtered ends and about the zone (102). The burn retardant band is perforated across its length so as to define a line of weakness. It should be noted that when manufacturing the breakable cigarette of the applicant's co-pending application, the burn retardant band will simply be a joining member which is perforated so as to provide a line of weakness at which the double cigarette may be broken into two, individually smokable cigarettes. Although not shown in Figure 6, two additional burn retardant bands (104) as shown in the embodiment of Figure 5, may also be wrapped around the bodies of the separate filtered cigarettes (96) at the time of joining them together at stage (G), or thereafter. The cigarette portions may also include additional zones underneath the additional bands (104) through which no tobacco strands pass, but abut on either side. It will be understood that these bands will prevent the cigarette from burning past the band if the cigarette is left unattended. The bands may, like the joining strip, be wrapped around the cigarette body once and glued onto itself, or it may be wrapped around the body more than once before being secured onto itself. Naturally, a double layered band will provide even more bum retardant properties than a single layer. The bands may therefore comprise any number of layers to achieve a desired level of burn retardation.

The joining strip (100) may also have no perforations. In such an embodiment the_cigarette. (80) may still-be^', broken between the individual filtered cigarettes (96), only the break will not be as clean as if the perforations were present. An advantage of such an embodiment is that the smoker may decide to break off one of the filters (106) and smoke the cigarette as a whole. The reduced ignition propensity cigarette so produced will then have three self-extinguishing zones at which the cigarette will stop burning if left unattended. It will be appreciated that any number of bands may be added to the cigarette and also that the bands may be manufactured from any material that retards burn to a sufficient degree so as to stop the cigarette from burning past it if left unattended.

The described method therefore produces a single reduced ignition propensity cigarette which may be broken into two, separately smokable, filtered cigarettes at the line of weakness.

As before, the machine used for applying the tipping paper at stage (D) may again be adapted to wrap the burn retardant bands, either simultaneously or in succession. It should also be appreciated that the tipping machine may also be adapted to wrap a burn retardant band around the body of a conventional, single filtered cigarette. In this way a reduced ignition propensity cigarette may be created by means of simple changes to existing tipping machines.

It should also be appreciated that the method described here with reference to Figure 6 could be part of a continuous process wherein a continuous length of cigarette rod is fed through the machine, cut at the required places, filters inserted, sections rotated and burn retardant bands wrapped about the sections at the required places.

The described method allows conventional cigarette making machines, as for example referred to in the background to the invention section, to be adapted by means of a few simple modifications and additions. The second swopping of the .positions_of .the -filtered. -cigarettes at stage (F) may, for example, be achieved by the same means used to swop the positions of the cigarette rod sections at stage (B), a function which is already performed in conventional prior art machines. Likewise, the machine used in known machines for joining the double filter and separated tobacco rod portions with tipping paper at stage (D), could be adapted to also wrap the burn retardant bands.

It is also foreseen that other fire and smoke retardant mechanisms may be used in combination with the features disclosed in this specification. In particular, it is foreseen that the cigarette may include a zone or plug of absorbent material to reduce the level of volatile smoke constituents in mainstream cigarette smoke.

It should be understood that numerous variations may be made to the embodiment of the method described above without departing from the scope thereof.