Patent Description:
Filter cigarettes typically comprise a cylindrical rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter axially aligned in an abutting end-to-end relationship with the wrapped tobacco rod. The cylindrical filter typically comprises a filtration material circumscribed by a paper plug wrap. Conventionally, the wrapped tobacco rod and the filter are joined by a band of tipping wrapper, normally formed of an opaque paper material that circumscribes the entire length of the filter and an adjacent portion of the wrapped tobacco rod.

A number of smoking articles in which tobacco is heated rather than combusted have also been proposed in the art. In heated smoking articles, an aerosol is generated by heating a flavour generating substrate, such as tobacco. Known heated smoking articles include, for example, electrically heated smoking articles and smoking articles in which an aerosol is generated by the transfer of heat from a combustible fuel element or heat source to a physically separate aerosol forming material. During smoking, volatile compounds are released from the aerosol forming substrate by heat transfer from the fuel element and entrained in air drawn through the smoking article. As the released compounds cool they condense to form an aerosol that is inhaled by the consumer. Smoking articles in which a nicotine-containing aerosol is generated from a tobacco material, tobacco extract or other nicotine source, without combustion or heating, are also known.

Sometimes it is desirable to provide the filter section of a smoking article with a cavity at the mouth end. However, such mouth end cavities are prone to collapse or deformation during manufacture of the smoking article and during subsequent handling by the consumer, particularly when the filtration material includes one or more breakable flavour containing capsules which must be ruptured by squeezing the filter prior to smoking.

<CIT> relates to a smoking article comprising a tobacco rod and a recess filter connected to the tobacco rod having a cavity located at its mouth end. The cavity is defined by a cavity wall and the recess filter comprises one or more filter elements. The cavity wall surrounds the cavity itself and part of a filter element.

It would therefore be desirable to provide a smoking article having a mouth end cavity which is resistant to collapse.

According to the present invention, there is provided a smoking article comprising a tobacco rod and a filter connected to the tobacco rod. The filter comprises a first filter segment comprising one or more breakable capsules dispersed within a fibrous filtration material, wherein each breakable capsule comprises an outer shell and an inner core containing an additive. The filter further comprises a hollow tube segment downstream of the first filter segment, the hollow tube segment positioned between a downstream end of the first filter segment and the mouth end of the filter. The hollow tube segment defines a cavity at the mouth end of the filter. A plug wrap circumscribes the first filter segment and the hollow tube segment, wherein the plug wrap has a basis weight of less than <NUM> grams per square metre.

In some embodiments, the hollow tube segment extends from the downstream end of the first filter segment to the mouth end edge of the filter.

As used herein, the terms "upstream" and "downstream" are used to describe the relative positions of elements, or portions of elements, of the smoking article in relation to the direction in which a user draws on the smoking article during use thereof. Smoking articles as described herein comprise a downstream end and an opposed upstream end. In use, a user draws on the downstream end of the smoking article. The downstream end, which is also described as the mouth end, is downstream of the upstream end, which may also be described as the distal end.

By forming a mouth end cavity with a hollow tube segment, the present invention advantageously provides a smoking article having a mouth end cavity with improved resistance to collapse or deformation. Such resistance to collapse or deformation can advantageously eliminate the need to use stiff, high basis weight plug wraps and tipping wrappers which might otherwise be required to prevent collapse of the mouth end cavity. Such high basis weight plug wraps and tipping wrappers are undesirable since they can become creased or folded during manufacture of the smoking article, and they can also add other costly steps to the manufacturing process such as the need for online laser perforation ventilation. Furthermore, high basis weight plug wraps and tipping wrappers can make it difficult for a consumer to deform the filter in order to break the one or more capsules contained therein. By eliminating the need for such high basis weight plug wraps and tipping wrappers and by forming the mouth end cavity using a hollow tube segment, smoking articles in accordance with the present invention allow a consumer to easily deform the filter at the first filter segment in order to break the one or more capsules contained therein, whilst ensuring the mouth end cavity is sufficiently resistant to deformation or collapse.

A smoking test used for testing smoking articles in accordance with the present disclosure is described in detail below.

In some embodiments, the hollow tube segment may be formed from a polymeric material or a paper material. For example, the hollow tube segment can be formed from an extruded plastic tube. Preferably, the hollow tube segment is formed from a plurality of overlapping paper layers, such as a plurality of parallel wound paper layers or a plurality of spirally wound paper layers. Forming the hollow tube segment from a plurality of overlapping paper layers can help to further improve resistance to collapse or deformation. Preferably each hollow tube segment comprises at least two paper layers. Alternatively, or additionally, each hollow tube segment preferably comprises fewer than eleven paper layers.

An exemplary method for forming a tube segment from a plurality of wound paper layers comprises wrapping a plurality of substantially continuous paper strips in an overlapping manner about a cylindrical mandrel. The strips are wrapped in a parallel manner or a spiral manner so as to form a substantially continuous tube on the mandrel. The formed tube may be turned about the mandrel, for example using a rubber belt, so that the paper layers are continually drawn and wrapped around the mandrel. The formed tube can then be cut into the required lengths downstream of the mandrel.

One factor that may restrict the ability of the hollow tube segment to retain its ovality during smoking of the smoking article is absorption of moisture into the hollow tube segment during smoking. Therefore, to inhibit the transfer of moisture from one paper layer to the next during smoking of the smoking article, adjacent paper layers of each tubular member are preferably adhered together by an intermediate layer of adhesive, which provides a barrier to the transfer of moisture between layers. Additionally, or alternatively, the hollow tube segment may comprise a coating layer on an inner surface thereof, which can inhibit absorption of moisture into the hollow tube segment. In those embodiments in which the hollow tube segment is formed from a plurality of paper layers, a coating layer may additionally or alternatively be provided between some or all of the adjacent paper layers. Suitable coating materials include, but are not limited to, waxes, polymeric materials and combinations thereof. Particularly suitable waxes include vegetable waxes, and other particularly suitable materials are ethylcellulose and nitrocellulose.

To assist in providing the required resiliency and resistance to deformation or crushing, the hollow tube segment preferably has a wall thickness of at least about <NUM> micrometres, more preferably at least about <NUM> micrometres. Alternatively, or in addition, the wall thickness is preferably less than about <NUM> micrometres, more preferably less than about <NUM> micrometres, most preferably less than about <NUM> micrometres.

The hollow tube segment preferably extends at least about <NUM> from the downstream end of the first filter segment in the finished cigarette. This not only provides a mouth end cavity of an appropriate size, but also ensures sufficient overlap between the hollow tube segment and any wrapper which may circumscribe the hollow tube segment to maintain it in axial alignment with the filter segment. Such wrappers include plug wraps and tipping wrappers. Additionally, or alternatively, the hollow tube segment preferably extends no more than about <NUM> from the downstream end of the first filter segment.

In some embodiments of the invention, it may be desirable to provide the filter with means for releasing a flavourant or other additive on demand, usually via manual release by the consumer immediately prior to smoking the article. Therefore, the filter may comprise at least one filter segment including a flavourant containing material, such as one or more breakable capsules comprising an outer shell and an inner core containing an additive. The at least one filter segment comprises one or more breakable capsules dispersed within a fibrous filtration material. The at least one filter segment may be the first filter segment, or an additional filter segment which may be incorporated into the filter, or a combination thereof.

Similarly, the additive contained within the one or more breakable capsules of smoking articles in accordance with the present invention may include a flavourant.

In embodiments comprising a flavourant containing material, in accordance with the present invention, the at least one flavour containing filter segment is preferably circumscribed by a plug wrap that is substantially impermeable to the flavourant additive. This advantageously inhibits transfer of the additive through the plug wrap to the outside of the smoking article, where it may undesirably come into contact with the consumer's fingers and may tarnish the appearance of the smoking article.

The crush strength of a capsule corresponds to the compressive force required to break open the capsule and release the additive contained within the capsule when the capsule is disposed within the filter segment. A capsule crush test is described in detail below.

As mentioned above, smoking articles according to the present invention may comprise additional filter segments in combination with the first filter segment. For example, in one embodiment, the smoking article further comprises a rod end segment between the first filter segment and the tobacco rod.

The filtration material within each filter segment of the smoking article is preferably a plug of fibrous filtration material, such as cellulose acetate tow or paper. A filter plasticiser may be applied to the fibrous filtration material in a conventional manner, by spraying it onto the separated fibres, preferably before applying any additional material to the filtration material. Smoking articles according to the present invention may also include a variety of different types of filter segments or combinations of filter segments that would be known to the skilled person, including restrictors and segments that are used for adjusting the resistance to draw (RTD). Alternatively, or in addition, smoking articles in accordance with the present invention may include one or more segments containing carbon, preferably a rod end segment containing carbon.

To connect the hollow tube segment to the first filter segment and any other filter segments which may be present, the smoking article comprise a plug wrap which circumscribes the various segments of the filter. The plug wrap has a basis weight of less than about <NUM> gsm, preferably less than about <NUM> gsm, more preferably less than about <NUM> gsm. The plug wrap preferably has a basis weight of more than about <NUM> gsm.

The smoking article may include a tipping wrapper circumscribing the filter and at least a portion of the tobacco rod so as to connect the filter to the tobacco rod. The tipping wrapper may comprise paper having a basis weight of less than about <NUM> gsm, preferably less than about <NUM> gsm. The tipping wrapper preferably has a basis weight of more than about <NUM> gsm.

Smoking articles according to the present invention may be filter cigarettes or other smoking articles in which the tobacco material is combusted to form smoke. Alternatively, smoking articles according to the present invention may be articles in which the tobacco material is heated to form an aerosol, rather than combusted. In one type of heated smoking article, the tobacco material is heated by one or more electrical heating elements to produce an aerosol. In another type of heated smoking article, an aerosol is produced by the transfer of heat from a combustible or chemical heat source to a physically separate tobacco material, which may be located within, around or downstream of the heat source. The present invention further encompass smoking articles in which a nicotine-containing aerosol is generated from a tobacco material without combustion or heating.

The present invention also provides a method of forming smoking articles, the method comprising a first step of providing a continuous array of first filter members and tubular members, wherein a tubular member is provided between each pair of consecutive first filter members. The first filter members each comprise one or more breakable capsules, each breakable capsule comprising an outer shell and an inner core containing an additive. The continuous array of first filter members and tubular members is then wrapped with a continuous sheet of plug wrap to form a wrapped filter array. The plug wrap has a basis weight of less than <NUM> gsm. Next, the wrapped filter array is cut at an intermediate position along each of the first filter members to provide multiple filter rods, each filter rod comprising two first filter segments and a tubular member positioned between the first filter segments. A tobacco rod is then provided in axial alignment with and adjacent to each first filter segment of each filter rod, and the filter rod and a portion of each tobacco rod are wrapped in a tipping wrapper. Finally, the tipping wrapper and the filter rod are cut at an intermediate position along the length of the tubular member to form multiple smoking articles, each smoking article comprising a tobacco rod connected to a filter. Each filter comprises a first filter segment and a hollow tube segment positioned between the adjacent filter segment and the mouth end of the filter, the hollow tube segment defining a cavity at the mouth end of the filter.

To simulate the smoking of a smoking article, the smoking article is subjected to a standard smoking test under ISO conditions (<NUM> puffs lasting <NUM> seconds each, every <NUM> seconds). In the ISO test method, the smoking article is smoked with the ventilation zone fully uncovered.

To perform a capsule crush test in accordance with the present disclosure, a smoking article including a breakable capsule is positioned between a lower plate having a diameter of <NUM> and an upper plate having a diameter of <NUM>. The portion of the smoking article housing the breakable capsule is positioned between the two plates such that the plates are centred on the location of the capsule. The smoking article and the capsule are then compressed by moving the upper plate towards the lower plate at a constant speed of <NUM> per minute. The force applied by the upper plate is increased until the capsule breaks, at which point the maximum compressive load applied by the upper plate is recorded as the crush strength of the capsule. The test is terminated when the maximum compressive load is reached and the upper plate is retracted to remove the compressive force from the smoking article. The smoking article is then left for <NUM> seconds to expand before any further tests or measurements are performed.

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

<FIG> show a filter cigarette <NUM> in accordance with the present invention. The cigarette <NUM> comprises a wrapped rod <NUM> of tobacco cut filler which is attached at one end to an axially aligned filter <NUM>. A tipping wrapper <NUM> circumscribes the filter <NUM> and a portion of the wrapped rod <NUM> of tobacco to join together the two portions of the cigarette <NUM>.

As shown in <FIG>, the filter <NUM> comprises a rod end filter segment <NUM>, a flavour containing filter segment <NUM>, and a mouth end hollow tube segment <NUM>. The segments <NUM>, <NUM> and <NUM> are circumscribed by a plug wrap <NUM> which connects the three segments to form the filter <NUM>. The plug wrap <NUM> has a basis weight of less than <NUM> gsm. One or more of the segments <NUM>, <NUM>, <NUM> may also be wrapped in an individual plug wrap.

The rod end filter segment <NUM> and the flavour containing filter segment <NUM> are formed of a suitable filtration material, such as cellulose acetate tow. Furthermore, the flavour containing filter segment <NUM> comprises a suitable flavourant provided in the form of one or more breakable capsules contained within the flavour containing filter segment <NUM>. The one or more breakable capsules may be ruptured by the consumer when desired by squeezing the flavour containing filter segment <NUM> between the consumer's fingers.

The mouth end hollow tube segment <NUM> defines a mouth end cavity <NUM> in the filter <NUM> which extends between the downstream end of the flavour containing filter segment <NUM> and the mouth end edge of the filter <NUM>. The mouth end hollow tube segment <NUM> may be formed of a plurality of spirally wound paper layers which can further improve the resistance to deformation of the mouth end cavity <NUM>, for example during the rupture of the one or more breakable capsules when present in the flavour containing filter segment <NUM>.

<FIG> shows an exemplary method of forming a tube member <NUM> which can be cut to form a plurality of hollow tube segments for use in forming smoking articles in accordance with the present invention. A plurality of continuous paper plies <NUM> are spirally wound around a cylindrical mandrel <NUM> in a staggered, overlapping arrangement. A suitable adhesive may be applied to one or more of the plies <NUM> using an adhesive bath <NUM> prior to winding each ply around the mandrel <NUM>. The plies <NUM> are driven by a rubber belt <NUM> so that the formed tubular member <NUM> rotates around the mandrel <NUM> until it is cut into desired lengths further downstream.

To form a plurality of smoking articles in accordance with the present invention, the process illustrated in <FIG> can be used. First, a plurality of filter rods is produced according to the process shown in <FIG>. A substantially continuous array of filter components is formed by providing a plurality of tubular members <NUM>, a plurality of flavour containing filter segments <NUM> and a plurality of rod end filter members <NUM>. A tubular member <NUM> is provided between each pair of consecutive rod end filter members <NUM>, and a flavour containing filter segment <NUM> is provided between each rod end filter member <NUM> and each tubular member <NUM>. The substantially continuous array of filter components is then wrapped in a continuous sheet of plug wrap <NUM> to form a wrapped filter array.

To form a plurality of filter rods, a plurality of first cuts <NUM> are made through at least some of the rod end filter members <NUM> of the wrapped filter array, each first cut <NUM> positioned at an intermediate position along the length of the respective rod end filter member <NUM>. The resilience of each tubular member <NUM> advantageously prevents collapse of the cavities defined therein during the cutting process and subsequent handling of the filter rods and smoking articles incorporating filters manufactured from the filter rods.

To form a dual filter rod, as shown in <FIG>, the wrapped filter array is cut through each rod end filter member <NUM> so as to provide a filter rod having a rod end filter segment <NUM> at each end, two flavor containing filter segments <NUM> positioned between the two rod end filter segments <NUM>, and a tubular member <NUM> positioned between the two flavor containing filter segments <NUM>. The dual filter rod essentially defines two smoking article filters <NUM> which are joined by a continuous plug wrap <NUM> and a tubular member <NUM>.

Alternatively, a quad filter rod, as shown in <FIG>, can be formed by cutting the wrapped filter array through every other filter member <NUM> so as to provide a filter rod which essentially comprises two joined dual filter rods.

The formed filter rods can be used to form two or more smoking articles. For example, as shown in <FIG>, a dual filter rod can be used to form two filter cigarettes <NUM> by placing a tobacco rod <NUM> in axial alignment with each end of the filter rod. A tipping wrapper <NUM> is then wrapped around the filter rod and a portion of each tobacco rod <NUM> adjacent the filter rod. The tipping wrapper <NUM>, the plug wrap <NUM> and the tubular member <NUM> are then cut along a cut line <NUM> to form two filter cigarettes. The resilience of the tubular member <NUM> prevents collapse or deformation of the mouth end cavities of each cigarette <NUM> during the cutting process.

Claim 1:
A smoking article (<NUM>) comprising:
a tobacco rod (<NUM>); and
a filter (<NUM>) connected to the tobacco rod (<NUM>), the filter (<NUM>) comprising:
a first filter segment (<NUM>) comprising one or more breakable capsules dispersed within a fibrous filtration material, each breakable capsule comprising an outer shell and an inner core containing an additive;
a hollow tube segment (<NUM>) downstream of the first filter segment (<NUM>) and defining a cavity (<NUM>) at the mouth end of the filter (<NUM>), the hollow tube segment (<NUM>) positioned between a downstream end of the first filter segment (<NUM>) and the mouth end of the filter (<NUM>); and
a plug wrap circumscribing the first filter segment and the hollow tube segment, wherein the plug wrap has a basis weight of less than <NUM> grams per square metre.