JP2014528711A - Smoking article filter including a flow restricting element and a cavity - Google Patents

Abstract

The smoking article (10) includes a flow restricting element (24) having a transverse barrier (28) that includes one or more orifices (38). The smoking article (10) defines a mouth end cavity (22) that extends from the transverse barrier (28) of the flow restricting element (24) to the mouth end of the smoking article. The flow restricting element (24) is preferably provided in the filter (14) and the mouth end cavity (22) is preferably at least partially defined by the filter wrapper (26). [Selection] Figure 1

Description

  The present invention relates to a smoking article filter including a combination of a flow restriction element and a mouth end cavity, and a smoking article incorporating such a filter.

  Filtered cigarettes typically include a cylindrical filter that is aligned in end-to-end relationship with the packaged tobacco rod and attached to the tobacco rod by chip paper. In conventional cigarettes with a filter, the filter can be composed of a plug of fibrous filtration material such as cellulose acetate tow wrapped with a porous plug wrap. During smoking, as smoke is drawn through the filter, particulate matter from mainstream smoke accumulates in the plug of cellulose acetate tow. This can result in discoloration or staining of the cellulose acetate tow plug, which is usually visible at the mouth end of the smoking article.

  Filters that incorporate one or more structural inserts are also known. For example, it is known to provide a filter that includes one or more flow restriction elements to increase the suction resistance (RTD) of a smoking article. Typically, a flow restricting element is provided in combination with a vent at a location along the filter to provide a filter that reduces delivery of gas phase components in mainstream smoke while maintaining an acceptable RTD. In previously proposed filters including a flow restriction element, one or more cellulose acetate tow plugs are provided at the mouth end of the filter downstream of the flow restriction element. After smoking, it can usually be seen that the cellulose acetate filter plug is stained at the mouth end of the smoking article.

International Publication No. 2009/022232 International Publication No. 2008/121610 International Publication No. 2010/107613

  It would be desirable to provide a smoking article filter with reduced staining at the mouth end of the filter or reduced visibility of staining. It would also be desirable to provide a smoking article filter that improves the mixing of mainstream smoke with circulating air entering the filter. It would be particularly desirable if a smoking article incorporating such a smoking article filter could improve the smoking experience of the smoking consumer.

  In accordance with the present invention, a smoking article is provided that includes a flow restricting element having a transverse barrier that includes one or more orifices. The smoking article defines an oral end cavity that extends from the transverse barrier of the flow restricting element to the oral end of the smoking article. The smoking article also includes a first downstream tubular portion that at least partially defines a mouth end cavity downstream of the transverse barrier. One or more openings are provided in the first downstream tubular portion so as to form a communication path between the outer periphery of the first downstream tubular portion and the mouth end cavity.

  Providing an opening in the flow restriction element has been found to advantageously improve the mixing of circulating air and mainstream smoke and further improve the distribution of the smoke stream delivered to the consumer. Thereby, generation | occurrence | production of the dyeing | staining in the mouth side edge part of a filter is further reduced. In addition, the smoke dispersion effect on the taste of smoke and the mouth sensation is enhanced.

  The smoking article according to the present invention preferably includes a filter defining a mouth end cavity including a flow restricting element and a filter wrapper surrounding the filter.

  In accordance with the present invention, there is further provided a filter including a flow restricting element having a transverse barrier including one or more orifices and a filter wrapper surrounding the filter. The filter defines a mouth end cavity that extends from the transverse barrier of the flow restricting element to the mouth end of the filter. The mouth end cavity is the space at the mouth end of the filter formed by one or more of the components of the filter. The filter also includes a first downstream tubular portion downstream of the transverse barrier that at least partially defines the mouth end cavity. One or more openings are provided in the first downstream tubular portion so as to form a communication path between the outer periphery of the first downstream tubular portion and the mouth end cavity.

  In the following description, all references to the filter according to the invention apply also to the filter of smoking articles according to the invention, unless otherwise specified.

  The filter according to the present invention can be advantageously used in filtered cigarettes and other smoking articles that burn tobacco material to produce smoke. The filter according to the invention can also be used in smoking articles that are heated to produce an aerosol rather than burning tobacco material. The filter according to the invention can also be used in smoking articles that generate nicotine-containing aerosols from tobacco material, tobacco extract or other nicotine sources without burning or heating.

  As used herein, the term “smoke” refers to smoke produced by combustible smoking articles such as filtered cigarettes, and aerosols produced by non-combustible smoking articles such as heated or non-heated smoking articles of the type described above. It is used to show.

  The term “flow restriction element” is used to indicate a structural filter insert that restricts the flow of mainstream smoke through the filter by reducing the size or cross section of the passage through which mainstream smoke must be drawn. is there. Reducing the size of the passage relative to the overall size of the filter makes it difficult to inhale smoke through the filter and increases the suction resistance. In the filter according to the invention, the flow restricting element has a transverse barrier comprising one or more orifices. Mainstream smoke is restricted to pass only through the orifice. The cross-sectional area of the passage or passages through which mainstream smoke must be drawn is preferably less than about 75%, more preferably less than about 50%, and less than about 10% of the total filter cross-sectional area. Most preferred.

  The terms “upstream” and “downstream” indicate the relative position of the components of the filter according to the present invention relative to the direction of mainstream smoke flow through the filter during smoking of a smoking article incorporating the filter according to the present invention. It is intended for use.

  The term “mouth end” refers to the end of a filter that is intended to be placed between the lips of a consumer during smoking. In the assembled smoking article, the mouth end of the filter is located at the end opposite the lit end of the smoking article.

  The term “transverse” refers to a component or direction that is substantially perpendicular to the longitudinal axis or major axis of the filter and smoking article.

  The filter according to the present invention incorporates a flow restriction segment to increase the suction resistance (RTD) of the filter. The flow restriction element is particularly applied to ventilation filters. The filter incorporates a vent to suppress delivery of mainstream smoke components such as tar or carbon monoxide. However, increasing the ventilation level may cause the RTD level to fall unacceptably. Thus, advantageously incorporating a flow restricting element in the filter can provide a filter that has an acceptable RTD but can still reduce tar and carbon monoxide delivery.

  The filter according to the invention includes a mouth end cavity. As will be described in more detail below, this cavity is formed or defined by one or more of the filter elements. Thus, the filter according to the present invention provides a space at the mouth end of the filter so that there is no further filter element between the flow restriction element and the mouth end of the filter. Thus, during smoking, the mainstream smoke passes through the orifice in the transverse barrier of the flow restricting element and then flows through the mouth end cavity without substantial obstruction and exits from the mouth end of the filter. .

  Providing the filter with a mouth end cavity means that the transverse barrier of the flow restricting element is visible from the mouth end of the filter. The inner surface of the mouth end cavity is also visible. Advantageously, the use of cavities instead of fibrous filtration material at the mouth end of the filter has been found to significantly reduce the visible staining of the filter after smoking. This filter configuration is such that mainstream smoke filtration downstream of the flow restricting element crossing barrier is minimized, and therefore, particulate matter from the mainstream smoke is minimally deposited. Specifically, a minimum amount of particulate matter is deposited on the visible surface at the mouth end of the filter.

  In addition, when the mouth end cavity is provided downstream of the transverse barrier of the flow restricting element, the flow dynamics of the mainstream smoke when sucked through the filter changes compared to the flow dynamics observed with the conventional filter configuration. In conventional filters that include a plug of filtration material as the most downstream element of the filter, mainstream smoke tends to be delivered to the consumer from the mouth end of the filter in the form of a concentrated smoke stream through the channel. In the filter according to the invention, mainstream smoke passes through one or more orifices in the transverse barrier and enters the mouth end cavity where it expands and disperses before being delivered to the consumer.

  If a ventilation is provided in the filter, the mouth end cavity is a space that allows the diluted smoke to be delivered from the mouth end of the filter after the mainstream smoke is more effectively mixed with some circulating air. Also provide.

  This dispersed smoke stream is likely to produce a different sensation in the consumer's mouth and may be preferred over the highly concentrated smoke stream from conventional filters.

  The mouth end cavity can extend at least about 2 mm from the transverse barrier to the mouth end of the filter to provide sufficient space for proper mixing and expansion of mainstream smoke. The mouth end cavity preferably extends at least about 5 mm from the transverse barrier, more preferably extends at least about 10 mm, and most preferably extends at least about 12 mm. Ventilation holes for supplying circulating air can be at least about 8 mm from the mouth end of the filter, preferably at least about 10 mm, and at least about 12 mm. It is more preferable.

  The mouth end cavity of the filter according to the invention is preferably at least partially defined by a filter wrapper. The term “partially defined” means that the filter wrapper defines the mouth end cavity along only a portion of its length. In a preferred embodiment, the mouth end cavity is at least partially defined by a filter plug wrap extending beyond the downstream end of the flow restricting element and defining a hollow cylindrical tube. The inner circumference of the tube defines a cylindrical cavity that forms all or part of the mouth end cavity of the filter. As will be described later, when the plug wrap defines only the downstream portion of the mouth end cavity in the longitudinal direction, the remaining portion of the mouth end cavity is preferably defined by the flow restricting element.

  The plug wrap is preferably formed of a paper material having a higher basis weight than conventional plug wrap materials when at least partially defining the mouth end cavity. This realizes a highly rigid plug wrap that forms a rigid hollow tube at the mouth end and avoids collapse of the mouth end cavity when the filter is pressed between the lips of the consumer. .

  The plug wrap can have a basis weight of about 40 grams per square meter to about 130 grams per square meter. Specifically, the plug wrap can have a relatively low basis weight of about 40 grams per square meter to about 60 grams per square meter, or a comparison of about 60 grams per square meter to about 130 grams per square meter. It can also have a high basis weight.

  Alternatively, the plug wrap can be formed of a plastic material such as a transparent plastic material. The basis weight of the plastic material can be about 40 grams per square meter to about 70 grams per square meter, and the plastic material can have a thickness of about 25 microns to 50 microns. In some embodiments, the plug wrap can be substantially non-porous, for example, its multipotency can be less than about 20 coresta units, more preferably less than about 10 coresta units. In other embodiments, the plug wrap can be porous, for example, its multipotency is greater than about 20 coresta units, more preferably greater than about 100 coresta units, and most preferably about 1000 coresta units. Can be larger.

  In some embodiments of the smoking article according to the invention, the tip paper attaching the filter to the rod of tobacco material in addition to or instead of the plug wrap may at least partially define the mouth end cavity. it can. For example, in some embodiments, both the plug wrap and the tip paper thereon have the same extent and extend beyond the downstream end of the flow restricting element to at least partially define the mouth end cavity. In another embodiment, the tip paper extends beyond the flow restricting element and the plug wrap and at least partially defines the mouth end cavity.

  The flow restricting element of the filter of the present invention includes a transverse barrier, which has one or more orifices that provide a restrictive passage for smoke passing through the barrier. The transverse barrier is formed of a smoke impermeable material so that this orifice effectively provides the only passage for smoke through the filter. The number of orifices provided in the transverse barrier and the dimensions of each orifice can be selected to achieve the desired RTD. The transverse barrier preferably includes a single, substantially central orifice. Alternatively, the transverse barrier can include a plurality of spaced orifices.

  The size of each orifice in the transverse barrier is preferably about 0.2 mm to about 1.2 mm, more preferably about 0.3 mm to about 0.8 mm, and about 0.5 mm to about 0.7 mm. Most preferably. The length of each orifice is preferably about 0.2 mm to about 2.0 mm, more preferably about 0.5 mm to about 0.7 mm. The term “length” is used to indicate the path length of the orifice from the upstream inlet of the orifice to the downstream outlet of the orifice. In a preferred embodiment, the length of the orifice is generally approximately equal to the thickness of the transverse barrier. The “size” of the orifice is what is used to indicate the maximum dimension across the orifice. In a preferred embodiment, the orifice shape is circular and the orifice size is the diameter of this circular shape.

  The transverse barrier of the flow restricting element can have any suitable shape. For example, the transverse barrier may be a substantially flat disk, preferably substantially perpendicular to the longitudinal axis of the filter. Alternatively, the crossing barrier may be frustoconical and may converge with respect to the direction of mainstream smoke sucked through the filter or may be divergent. In further embodiments, the transverse barrier can also be concave or convex with respect to the direction of mainstream smoke sucked through the filter. The transverse barrier is preferably concave with respect to the mainstream smoke direction, i.e. concave in the upstream direction. This has the advantage that the flow restricting element can be easily compressed during the manufacture of the filter according to the invention.

  The inner circumference of the first downstream tubular portion at least partially defines the mouth end cavity. If the first downstream tubular portion extends from the transverse barrier to the mouth end of the filter, the mouth end cavity can be completely defined by the first downstream tubular portion in the filter. Alternatively, as described above, the mouth end cavity is an integral of an upstream portion defined by the first downstream tubular portion and a cavity defined by a filter wrapper extending beyond the end of the first downstream tubular portion. And a downstream portion.

  The first downstream tubular portion preferably has an outer diameter that is reduced compared to the outer diameter of the filter. Accordingly, there is an annular space in the packaging filter between the filter wrapper and the outer surface of the first downstream tubular portion. As will be described in more detail below, this annular space can be advantageously used to provide a ventilation region within the filter.

  This configuration allows air to be drawn through this ventilation region during smoking and directed directly into the mouth end cavity through the opening in the first downstream tubular portion.

  The flow restricting element can further include a second downstream tubular element downstream of the first downstream tubular element. The second downstream tubular element is preferably connected to the first downstream tubular element such that there is no gap between adjacent ends of both downstream tubular elements. It is particularly preferred that the first and second downstream tubular portions are integrally formed. The inner circumference of the second downstream tubular portion defines a portion of the mouth end cavity, along with the portion defined by the first downstream tubular element and optionally the filter wrapper. The second downstream tubular portion preferably has an outer diameter that substantially corresponds to the outer diameter of the filter. This advantageously provides the filter with structure and reinforcement to prevent collapse of the filter, particularly when the outer diameter of the first downstream tubular portion is reduced compared to the second downstream tubular portion.

  The flow restricting element preferably includes an upstream tubular portion that extends upstream from the transverse barrier instead of or in addition to the one or more downstream tubular portions. The inner circumference of the upstream tubular portion defines an upstream cavity. The outer diameter of the upstream tubular portion is preferably substantially the same as the outer diameter of the filter. The upstream cavity can have the advantage of allowing mainstream smoke to be drawn downstream through the orifice after concentrating around one or more orifices in the transverse barrier. The upstream cavity can also help prevent blockage of one or more orifices during smoking.

  The flow restricting element can include a second upstream tubular portion upstream of the first upstream tubular portion in a configuration similar to that described above with respect to the first and second downstream tubular portions. Where two upstream tubular portions are provided, the outer diameter of the first upstream tubular portion adjacent to the transverse barrier is preferably reduced compared to the overall diameter of the filter, and the outer diameter of the second upstream tubular portion is substantially In particular, it is preferably the same as the filter.

  In a particularly preferred embodiment, two integral tubular portions are provided downstream of the transverse barrier and a single tubular portion is provided upstream of the transverse barrier.

  The tubular portions on both sides of the transverse barrier can have substantially the same size and shape as each other so that the flow restricting elements are symmetrical about the transverse barrier. Alternatively, the tubular portions on both sides of the transverse barrier can have different sizes or shapes so that the flow restricting elements are asymmetric about the transverse barrier.

  Although it is possible to form a flow restricting element consisting of two or more connecting parts, the components of the flow restricting element are preferably integrally formed as a single integral element. The flow restricting element is preferably formed by extrusion or injection molding.

  The flow restricting element can be formed of any suitable material or combination of materials. The flow restricting element is preferably formed of a material suitable for extrusion or injection molding. The flow restricting element is preferably formed of a material that has a lower particle efficiency than conventional cellulose acetate filter material so as not to retain as much particulate matter in the mainstream smoke that passes therethrough. Suitable materials that can form the flow restricting element include, but are not limited to, plastics (eg, polypropylene, polyethylene, polystyrene, nylon, polysulfone, polyester, polyurethane, poly (hydroxyalkanoic acids), poly (butylene). Succinate), poly (vinyl acetate), poly (hydroxybutyrate hydroxyvalerate, poly (butylene adipate terephthalate or polycaprolactone), cellulose material, starch-based material, polylactic acid, polyvinyl alcohol, and combinations or composites thereof. Can be mentioned.

  The flow restricting element is preferably formed from a soluble polymeric material formed from one or more water soluble polymers. It is particularly preferred that the soluble polymer material is formed of one or more water soluble thermoplastics. The term “solubility” means that the polymeric material can be dissolved in solution by an aqueous solvent. This is accomplished by forming the material using one or more water soluble materials. The flow restricting element can be formed entirely of a soluble polymer material, or the soluble polymer material is combined with an inert component such as an inert inorganic filler that may or may not be soluble. You can also. By using a dissolvable material to form the flow restricting element, the degradation rate of the filter after discarding the filter is advantageously increased.

  It is particularly preferred that the flow restricting element is formed from a biodegradable polymer material. Preferred polymers are completely biodegradable as defined in the aqueous aerobic biodegradation test (Sturm test) outlined in the European standard EN13432. Preferred biodegradable polymers include starch, polyvinyl alcohol, and combinations thereof.

  The thickness of the material forming the flow restricting element is preferably from about 0.2 mm to about 2.0 mm, more preferably from about 0.5 mm to about 0.7 mm. For example, the thickness of the transverse barrier and the thickness of the walls forming the upstream and downstream tubular portions are preferably within these ranges.

  The length of the flow restricting element is preferably about 6 mm to about 20 mm, and more preferably about 6 mm to about 14 mm. The ratio of the flow restricting element length to the flow restricting diameter is preferably at least about 1.2, more preferably at least about 1.5, and most preferably at least about 1.8. Where the flow restricting element includes one or more tubular portions, the length of each tubular portion is preferably at least about 3 mm, more preferably at least about 4 mm. The outer diameter of the flow restricting element is preferably about 6 mm to about 9 mm, more preferably about 7 mm to about 8.5 mm, and about 7.5 mm to about 7.9 mm for a standard size cigarette, Alternatively, it is most preferable that the diameter is about 6.6 mm to about 7.6 mm for small-diameter cigarettes.

  The filter and the smoking article according to the present invention preferably include a ventilation region at a position along the filter in order to allow air to flow into the filter during smoking. Circulating air entering the filter diminishes mainstream smoke and reduces carbon monoxide and tar delivery during smoking. The ventilation region preferably takes the form of a row of one or more circumferential perforations through the tip paper that attaches the filter to the rod of tobacco material. This perforation is preferably provided through both the tip paper and the plug wrap if the underlying plug wrap is substantially air impermeable. The perforations can also extend through the chip paper only if the underlying plug wrap is at least partially air permeable.

  The ventilation region can supply circulating air upstream or downstream of the transverse barrier of the flow restriction element. Circulating air is preferably supplied downstream of the transverse barrier. Circulating air is preferably supplied into the first downstream tubular portion.

  As described above, the first downstream tubular portion preferably has an outer diameter that is reduced compared to the overall outer diameter of the filter. Thereby, in embodiment which provided the ventilation area | region on the 1st downstream tubular part, the annular space formed between chip | tip paper and the outer periphery of the 1st downstream tubular part forms the space which draws in circulating air. This is particularly advantageous. This configuration improves mainstream smoke ventilation.

  Each opening in the first downstream tubular portion preferably includes a passage extending through the wall of the first downstream tubular portion from the outer surface to the inner surface. When viewed in a longitudinal section, the passage may be inclined upstream, downstream, or perpendicular to the longitudinal axis of the filter. This passage preferably extends at an angle alpha (α) that is non-perpendicular to the longitudinal axis of the filter. For example, the angle alpha (α) is preferably about 30 degrees to about 90 degrees in the upstream or downstream direction, and more preferably about 45 degrees to about 90 degrees in the upstream or downstream direction. The angle alpha (α) is measured as the minimum angle between the central axis of the passage and the longitudinal axis of the filter. If the passage is not straight, the angle alpha (α) is measured between the longitudinal axis of the filter and the exit direction of the passage.

  In some embodiments, all passages direct air downstream toward the mouth end. In other embodiments, all the passages guide air in the upstream direction away from the mouth end. In yet another embodiment, a portion of the passage directs smoke upstream and the remainder directs smoke downstream.

  Providing an opening or passage inclined relative to the longitudinal direction of the smoking article means that the circulating air is directed into the mouth end cavity at an angle to the mainstream smoke flow during smoking. To do. This advantageously optimizes the mixing of smoke and air and disperses the mainstream smoke flow. This mixing can also increase the turbulence of the smoke and air flow passing through the mouth end cavity. These effects on the flow dynamics of mainstream smoke can enhance the advantages described above.

  In the cross section of the flow restricting element, each passage preferably extends along a radius of the cross section or along a line offset from the radius by an angle beta (β). “Radius” means any line extending from the center of the cross section to the edge of the cross section. The angle beta (β) is measured as the minimum angle between the intersection of the radius and the central axis of the passage. If the passage is not straight, this angle can be measured between the longitudinal axis of the filter and the passage outlet.

  When the cross section is viewed from the downstream direction, the angle beta (β) may be directed clockwise with respect to the radius, or may be directed counterclockwise.

  If the passage is offset from the radius, the angle beta (β) is preferably less than about 60 degrees, more preferably less than about 45 degrees, clockwise or counterclockwise, and about 15 Most preferably, it is less than degrees. If the angle beta (β) is offset from the radius, the mixing of smoke and circulating air can be enhanced. In some cases, all the passages can be oriented clockwise or counterclockwise, or some of the passages can be directed clockwise and some can be oriented counterclockwise.

The size of the opening or passage in the first downstream tubular portion preferably provides a total open area of about 1.0 to about 4.0 square mm (mm ² ), which is about 1. More preferably, it is 5 to about 3.5 mm ² (mm ² ). The openings or passages are preferably substantially circular or elliptical, but other shapes of cross sections are possible.

  A single opening or passage may be provided in the first downstream tubular portion. Alternatively, two or more spaced openings or passages can be provided in the first downstream tubular portion. For example, in one preferred embodiment, a pair of substantially opposed passages is provided. If there are two or more openings or passages, these openings or passages may have the same open area or different open areas. The two or more passages can be provided at the same or different angle alpha (α) relative to the longitudinal axis and at the same or different angle beta (β) relative to the radius of the cross section of the flow restricting element. The openings or passages can be located at substantially the same location along the length of the first downstream portion or at different longitudinal locations.

  In another embodiment in which a ventilation region is provided upstream of the crossing barrier, the ventilation region preferably overlies the upstream tubular portion of the flow restricting element. In such an embodiment, the upstream tubular portion forms a communication path between the upstream cavity formed by the upstream tubular portion and the ventilation region, as described above with respect to the opening in the first downstream tubular portion. As such, it may include one or more openings. In such an embodiment, the mainstream smoke and circulating air are mixed before the smoke passes through the crossing barrier.

  Where the flow restricting element includes two upstream tubular portions, the opening is preferably provided in the first upstream portion adjacent to the transverse barrier. The first upstream portion may have an outer diameter that is reduced relative to the overall diameter of the filter so as to form an annular channel between the outer surface of the first upstream tubular portion and the overlying plug wrap. preferable.

  The filter according to the invention can further comprise one or more additional filter segments upstream of the flow restriction element. Upstream of the flow restricting element is one or more consisting of a fibrous filtration material such as one or more of cellulose acetate tow, cellulose nonwoven (eg paper), cellulosic yarn, water soluble fiber and biodegradable fiber. More plugs are preferably provided. The length of each filtration material plug is preferably about 5 mm to about 12 mm, and more preferably about 6 mm to about 8 mm. The fibers that form the fibrous filtration material may be substantially longitudinally aligned along the segments or may be randomly oriented.

  Where an upstream plug of one or more fibrous filtration materials is provided, the at least one plug can include an adsorbent capable of removing at least one gas phase component from mainstream smoke drawn through the filter. The at least one adsorbent is preferably selected from the group consisting of activated carbon, activated alumina, zeolites, sepiolites, molecular sieves and silica gel. Alternatively or in addition, the plug of at least one fibrous filtration material may include one or more flavors, preferably one, to further enhance flavor delivery to the consumer during smoking. Or more liquid flavors can be included.

  The flow restricting element and, if present, the upstream plug of one or more fibrous filtration materials are preferably surrounded by a strip of plug wrap. The plug wrap may be substantially air permeable or substantially air impermeable. As mentioned above, this strip-shaped plug wrap preferably extends beyond the downstream end of the flow restricting element and at least partially defines a mouth end cavity.

  The strip-shaped plug wrap is preferably attached to at least a circumferential outer surface of the flow restricting element. The strip-shaped plug wrap is preferably attached to the flow restriction element so as to form a substantially airtight seal on the outer surface of the flow restriction element. This advantageously prevents mainstream smoke from leaking around the outside of the flow restricting element during smoking, and substantially all of the mainstream smoke must pass through one or more orifices in the transverse barrier. Disappear. In this way, the flow restriction element can effectively maintain the desired RTD level.

  Where the filter further comprises one or more upstream plugs of fibrous filtration material, the strip-shaped plug wrap is preferably attached to the outer circumferential surface of each plug.

  The plug wrap is preferably formed of a paper material. However, the plug wrap can alternatively be made of a plastic material, for example a transparent plastic material. The strip-shaped plug wrap can be attached to the flow restriction element and any filter plug using a suitable adhesive.

  When the RTD is measured with all ventilations blocked, the total RTD of the filter according to the present invention is preferably about 250 mmWG to about 500 mmWG, more preferably about 275 mmWG to about 400 mmWG, and about 300 mmWG to about 400 mmWG. Most preferably. When the RTD is measured before smoking with all ventilation blocked, the total RTD of the smoking article according to the present invention is preferably at least about 30 mmWG, more preferably at least about 40 mmWG.

  In this specification, RTD of a filter or a smoking article is expressed in pressure units of “mmWG”, that is, “water level gauge mm”, and measured according to ISO 6565: 2002.

  The total length of the filter according to the present invention is preferably about 18 mm to about 36 mm, more preferably about 27 mm. The total length of the smoking article according to the present invention is preferably from about 70 mm to about 128 mm, more preferably about 84 mm. The outer diameter of the filter and smoking article according to the present invention is preferably about 5 mm to 8.5 mm, and more preferably about 7.9 mm.

  Filters according to the present invention can be advantageously incorporated into a variety of different types of smoking articles. For example, a filter according to the present invention can be incorporated into a combustible smoking article, such as a filtered cigarette having a rod of tobacco cut filler or other smokable material that burns during smoking. The rod of smokable material preferably comprises tobacco surrounded by a wrapper, and more preferably comprises tobacco cut filler surrounded by the wrapper.

  Alternatively, a filter according to the present invention can be incorporated into a heated smoking article of the type described above that heats the material rather than burning it to produce an aerosol. For example, a filter according to the present invention is a heated smoking article with a flammable heat source as disclosed in WO 2009/022232, comprising a flammable heat source and an aerosol generating substrate downstream of the flammable heat source. Can also be incorporated. The filter according to the present invention can also be incorporated into a heated smoking article with a non-flammable heat source, such as a chemical heat source or an electrical heat source such as an electrical resistance heating element.

  Alternatively, the filter according to the present invention produces a nicotine-containing aerosol from tobacco material or other nicotine source without combustion or heating, as described in WO2008 / 121610 and WO2010 / 107613. It can also be incorporated into smoking articles.

  The smoking article according to the present invention can be packed in a container such as a soft pack or a hinge lid pack. The smoking article in the container can be packaged with an inner liner and optionally a flavoring added to at least one surface of the inner liner.

  The filter according to the present invention comprises the steps of providing a continuous array of filters including a flow restricting element and any further upstream filter segments, and wrapping the continuous array of these filters with a continuous sheet of plug wraps. Cutting the packaging filter rod to form individual filters or multiple filters such as double or quadruple filters. These filters are preferably arranged in a continuous array so that a space is formed adjacent to the downstream end of the flow restricting element. These individual or multiple packaging filter rods are then combined with tobacco material packaging rods in a known process to provide an assembled smoking article. As described above, the filter rod is cut in space to provide a filter having a mouth end cavity formed by a plug wrap.

  The flow restricting elements and any additional upstream filter segments can be aligned and placed in a suitable order to form a continuous array of filters using conventional filter manufacturing equipment and techniques. If the flow restriction element is asymmetric along its length, it may be necessary to alternate the direction of the flow restriction element so that the correct direction is obtained in all assembled filters. Continuous wrap filter rods are cut in place using conventional cutting equipment, using means suitable for registering the cutting position so that a consistent length of mouth end cavity is produced can do.

  During the manufacture of the filter, suitable for the inner surface of the plug wrap, the outer surface of the filter element or both so that the plug wrap adheres to the outer peripheral surface of the filter element after wrapping the plug wrap around the continuous array of filters. It is preferable to apply an adhesive.

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

FIG. 3 is a perspective view of a smoking article according to the present invention with chip paper and plug wrap partially removed so that the internal components of the filter are clear. It is a figure which shows the longitudinal direction cross section of the filter of the smoking article of FIG. It is a figure which shows the cross section of the filter cut off at the position of the line of perforation. FIG. 6 shows a longitudinal section through a filter according to another embodiment of the invention.

  A smoking article 10 shown in FIG. 1 includes a cylindrical tobacco rod 12 and a filter 14. The tobacco rod 12 includes a plug of tobacco cut filler surrounded by a paper wrapper 16. The filter 14 is attached to the tobacco rod 12 by a strip-shaped chip paper 18 that surrounds the filter 14 and the adjacent portion of the tobacco rod 12.

  Filter 14 includes upstream filter segment 20 that abuts tobacco rod 12, mouth end cavity 22 at the mouth end of smoking article 10, and between upstream filter segment 20 and mouth end cavity 22. And an integrally formed injection molded flow restricting element 24. The upstream filter segment 20 is formed of a plug of cellulose acetate tow. The upstream filter segment 20 is separated from the upstream end of the flow restricting element 24 by a small distance.

  The upstream filter segment 20 and the flow restriction element 24 are surrounded by a strip-shaped plug wrap 26. A strip-shaped plug wrap 26 extends beyond the downstream end of the flow restricting element 24 and partially defines the mouth end cavity 22 of the filter. The strip-shaped chip paper 18 extends over the entire length of the filter so as to overlap the plug wrap 26 including the mouth end cavity 22.

  The flow restricting element 24 is formed of polyvinyl alcohol that is injection molded to blend with an organic or inorganic filler material to form the flow restricting element 24. As shown in FIG. 2, the flow restricting element 24 includes a central transverse barrier 28, an integral downstream tubular portion 30 extending from the downstream side of the barrier 28, and an integral upstream tubular portion 32 extending from the upstream side of the barrier 28. Including.

  The inner circumference of the downstream tubular portion 30 defines a downstream cavity 34 adjacent to the transverse barrier 28, which together with the space defined by the plug wrap 26 forms part of the mouth end cavity 22. The inner circumference of the upstream tubular portion 32 similarly defines an upstream cavity 36 adjacent the transverse barrier 28 on the opposite side. The tubular portions 30 and 32 have substantially the same length as each other, and both outer diameters substantially correspond to the outer diameter of the filter 14.

  The transverse barrier 28 takes the form of a disk having an outer diameter corresponding to the outer diameter of the filter 14. The disc includes a single central orifice 38 that forms a passage between the downstream cavity 34 and the upstream cavity 36. As shown in FIG. 1, the outer surface of the transverse barrier 28, the downstream tubular portion 30, and the upstream tubular portion 32 are integral so that the outer surface of the flow restricting element 24 is generally substantially cylindrical. The walls of the transverse barrier 28 and the tubular portions 30, 32 have a thickness of 0.5 mm to 0.7 mm.

  A pair of substantially opposing passages 40 are provided in the downstream tubular portion 30. Each passage 40 extends through the wall of the downstream tubular portion 30 at an angle alpha (α) of about 90 degrees with respect to the longitudinal axis of the smoking article.

  As shown in FIG. 3, when viewed in cross-section, each passage 40 circumferentially surrounds the downstream tubular portion 30 such that it extends at an angle beta (β) relative to the radius of the cross-section of the flow restricting element. Extend to. In another embodiment, the angle beta (β) can be zero degrees so that each passage extends along the radius of the downstream tubular portion, or the angle beta (β) is clockwise from the radius, as shown. It can also be offset in the direction by an angle of less than about 45 degrees.

  The strip-shaped chip paper 18 and the strip-shaped plug wrap 26 are provided with a row of perforations 50 in the circumferential direction passing therethrough. The perforation 50 exists along the filter 14 at a position overlapping the opening of the passage 40 on the outer surface of the downstream tubular portion 30. Accordingly, the passage 40 forms a communication passage between the outside of the filter and the mouth side end cavity 22 so that the circulating air is sucked into the mouth side end cavity 22. In use, circulating air is drawn through the perforation 50 and enters the mouth end cavity 22 along the passage 40 in the downstream tubular portion where it mixes with mainstream smoke drawn through the central orifice 38 of the transverse barrier 28. The The arrangement of the passage 40 means that the circulating air is directed into the mainstream smoke at an angle perpendicular to the direction of the mainstream smoke. Thereby, circulating air and mainstream smoke are mixed, and the turbulent flow of smoke and air is generated.

  The filter 114 shown in FIG. 4 is structurally similar to the filter 14 described above, but includes another flow restriction element 124. The flow restricting element 124 includes a central transverse barrier 128, a first integral downstream tubular portion 130, a second integral downstream tubular portion 131, and an upstream integral tubular portion 132 as described above. The transverse barrier 128 is recessed in the upstream direction.

  The first downstream tubular portion 130 extends from the downstream side of the transverse barrier 128 and has an outer diameter that is reduced compared to the overall diameter of the filter. The second downstream tubular portion 131 extends from the downstream end of the first downstream tubular portion 130. The upstream tubular portion 132 extends from the upstream side of the transverse barrier 128. Both the second downstream tubular portion 131 and the upstream tubular portion 132 have an outer diameter that is substantially the same as the diameter of the filter 114.

  The inner circumference of the first downstream tubular portion 130 and the second downstream tubular portion 131 defines a downstream cavity 134 adjacent to the transverse barrier 128, which downstream cavity 124 is formed by the plug wrap 26 as in the case of the filter 14. A part of the mouth end cavity 122 is formed together with the defined space.

  As shown in FIG. 2, the inner surface of the plug wrap 126 has a reduced outer diameter of the first downstream tubular portion 130 compared to the tubular portions on both sides, so that the circumferential direction of the first downstream tubular portion 130 is reduced. Separate from the outer surface. The annular space between the plug wrap 26 and the outer surface of the first downstream tubular portion 130 forms a ventilation region. The plug wrap 26 and chip paper 18 overlying the first downstream tubular portion 130 are provided with a row of one or more circumferential perforations 140 therethrough.

  As with the filter 14, a pair of substantially opposed passages 140 are provided in the first downstream tubular portion 130. These passages have the same configuration as described above with respect to the filter 14.

  When the above-described filters 14 and 114 are viewed from the mouth end, the inner surfaces of the mouth end cavities 22 and 122 can be seen. At the mouth end of the mouth end cavity, this inner surface corresponds to the inner surface of the plug wrap 126. In the portion defined by the flow restricting element 124 of the mouth end cavity 122, this inner surface corresponds to the inner surface of the downstream portion 30 or one or more downstream portions 130, 131. Also visible from the mouth end is a transverse barrier 28, 128 having a central orifice 38. After smoking by smoking article 10 incorporating filter 14 or filter 114 by burning tobacco material in tobacco rod 12, the staining on the visible surface of mouth end cavities 22, 122 and transverse barriers 28, 128 is not observed. The degree is relatively low.

  The filters 14 and 114 are constructed using the method described above. A continuous array of flow restricting elements 24, 124 is arranged with the upstream filter segment 20 adjacent to the upstream of each flow restricting element 24, 124 and a space formed downstream. A continuous sheet of plug wrap material is also prepared and the plug wrap sheet is wrapped around an array of filter segments and glued in place. Next, the wrapping filter rod is combined with the wrapping tobacco rod by cutting successive wrapping filter rods to form individual double or quadruple wrapping filters and attaching a strip of chip paper around the filter. . This step can be performed using existing machinery used to attach the filter to the tobacco rod during the manufacture of known filter cigarettes.

DESCRIPTION OF SYMBOLS 10 Smoking article 12 Tobacco rod 14 Filter 16 Paper wrapper 18 Chip paper 20 Upstream filter segment 22 Mouth end cavity 24 Flow restricting element 26 Plug wrap 28 Transverse barrier 30 Downstream tubular portion 40 Passage 50 Perforation

Claims (14)

A smoking article,
Including a flow restricting element having a transverse barrier including one or more orifices, the smoking article defining a mouth end cavity extending from the transverse barrier of the flow restricting element to the mouth end of the smoking article; The smoking article is
A first downstream tubular portion further defining at least partially the mouth end cavity downstream from the transverse barrier, the first downstream tubular portion including an outer periphery of the first downstream tubular portion and the One or more openings are provided to form a communication path between the mouth end cavities;
A smoking article characterized by that. A filter including the flow restricting element and a filter wrapper surrounding the filter, the filter defining the mouth end cavity;
The smoking article according to claim 1. The filter wrapper at least partially defines the mouth end cavity in the filter;
The smoking article according to claim 2. The outer diameter of the first downstream tubular portion of the flow restricting element is reduced compared to the outer diameter of the smoking article;
A smoking article according to any one of claims 1 to 3. The one or more openings extend through the wall of the first downstream tubular portion at a non-perpendicular angle alpha (α) of 30 to 90 degrees with respect to the longitudinal axis of the smoking article. Including further passages,
The smoking article according to any one of claims 1 to 4. The one or more openings extend substantially perpendicular to the longitudinal axis of the smoking article;
The smoking article according to any one of claims 1 to 4. The one or more openings include one or more passages extending through the wall of the first downstream tubular portion, the passages being relative to a radius of a cross section of the flow restricting element. Extending at an angle beta (β) offset from the angle by less than about 45 degrees,
The smoking article according to any one of claims 1 to 6. The flow restricting element further includes a second downstream tubular portion downstream of the first downstream tubular portion that at least partially defines the mouth end cavity.
The smoking article according to any one of claims 1 to 7, wherein The mouth end cavity of the filter extends at least 2 mm downstream from the transverse barrier of the flow restricting element in the smoking article;
A smoking article according to any one of claims 1 to 8. The flow restricting element further includes one or more upstream tubular portions defining an upstream cavity upstream of the transverse barrier,
The smoking article according to any one of claims 1 to 9. A ventilation region is provided at a location along the smoking article that includes a row of at least one circumferential perforation provided through a portion of the smoking article wrapper.
The smoking article according to any one of claims 1 to 10, wherein the article is a smoking article. The ventilation region is provided on the first downstream tubular portion so as to form a communication path through the one or more openings between the ventilation region and the mouth end cavity.
The smoking article according to claim 11. The ventilation region further includes an annular space between an inner surface of a portion of the smoking article wrapper and an outer surface of the first downstream tubular portion,
The smoking article according to claim 11 or 12, wherein the article is a smoking article. A filter for smoking articles,
A flow restricting element having a transverse barrier including one or more orifices and further comprising a first downstream tubular portion downstream of the transverse barrier;
A filter wrapper surrounding the filter;
Including
The filter defines a mouth end cavity extending from the transverse barrier of the flow restricting element to a mouth end of the filter, and the first downstream tubular portion at least partially defines the mouth end cavity. And defining one or more openings in the first downstream tubular portion so as to form a communication path between an outer periphery of the first downstream tubular portion and the mouth end cavity.
A filter characterized by that.

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