Patent Publication Number: US-7914622-B2

Title: Smoking article having flavorant materials retained in hollow heat conductive tubes

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Patent Provisional Application No. 60/751,995, filed Dec. 21, 2005, which is incorporated herein by this reference in its entirety. 
    
    
     BACKGROUND 
     Smoking articles, particularly cigarettes, generally comprise a tobacco rod of shredded tobacco (usually, in cut filler form) surrounded by a paper wrapper, and a cylindrical filter aligned in an end-to-end relationship with the tobacco rod. The tobacco rod is generally between 7.0 and 10.0 millimeters in diameter and 60 millimeters and 125 millimeters in length. Typically, the filter includes a plug of cellulose acetate tow attached to the tobacco rod by tipping paper. Ventilation of mainstream smoke can be achieved with a row or rows of perforations about a location along the filter. 
     SUMMARY 
     It would be desirable for smoking articles to have an effective flavor delivery system that has a capacity to bypass an adsorbent material within the filter system, whereby losses of flavorant are avoided and effectiveness of the adsorbent is maintained. 
     In accordance with one embodiment, a smoking article comprises: a cylinder of smoking material; a filter system attached to the cylinder of smoking material, the filter system having an adsorbent material; at least one hollow tube having a heat conductive wall within the cylinder of smoking material, the at least one hollow tube extending from within the cylinder of smoking material through the adsorbent material; and at least one flavorant material retained within the at least one hollow tube, and wherein the flavorant material releases a flavorant upon exposure to heat from the heat conductive wall of the hollow tube. 
     In accordance with a further embodiment, a smoking article comprises: a cylinder of smoking material containing at least one hollow tube within the cylinder of the smoking material, the at least one hollow tube having a heat conductive wall; and a filter system attached to the cylinder of smoking material, the filter system having an adsorbent material located between upstream and downstream filtering material and wherein the at least one hollow tube extends from within the cylinder of smoking material through the upstream filtering material and adsorbent material into the downstream filtering material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a smoking article according to one embodiment having flavorant materials retained in a hollow tube of a heat conductive material, wherein the tipping material has been partially unfolded to reveal the filter system. 
         FIG. 2  shows a cross sectional view of  FIG. 1  having a hollow tube of a heat conductive material with flavorant materials retained in the hollow tube. 
         FIG. 3  shows a cross sectional view of another embodiment of a smoking article having a plurality of hollow tubes of a heat conductive material with flavorant materials retained in the hollow tubes. 
         FIG. 4  shows a cross sectional view of a further embodiment of a smoking article having a plurality of hollow fibers of a heat conductive material with flavorant materials retained in the hollow fibers. 
         FIG. 5  shows a cross sectional view of  FIG. 2  along the line A-A. 
         FIG. 6  shows a cross sectional view of  FIG. 3  along the line B-B. 
         FIG. 7  shows a cross sectional view of  FIG. 4  along the line C-C. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a smoking article  10  in the form of a cigarette having at least one hollow tube  60  (not shown), wherein the tipping material  50  has been partially unfolded to reveal the filter system  40 . Smoking articles  10  in the form of cigarettes typically include a generally cylindrical rod  20  of smoking material  21  ( FIG. 2 ), contained in a circumscribing outer wrapper  30 . The outer wrapper  30  is typically a porous wrapping material or paper wrapper. The rod  20  is typically referred to as a “tobacco rod” and has a lit end  12  and a mouth end  14 . The tobacco rod  20  is used by lighting one end thereof, and aerosol (e.g., smoke) is provided as a result of the combustion of the burning smoking material  21 , which is lit at a lit end  12 . As such, the tobacco rod  20  burns back from the lit end  12  thereof towards the opposite end (i.e., mouth end  14 ) thereof, and the smoking material  21  of the tobacco rod  20  is consumed by combustion during smoking. The smoking material  21  is preferably a shredded tobacco or tobacco cut filler. However, any suitable smoking material  21  can be used. 
     The smoking article  10  also includes a filter system (or filter)  40  adjacent to the mouth end  14  of the tobacco rod  20  such that the filter system  40  and tobacco rod  20  are axially aligned in an end-to-end relationship, preferably abutting one another. The filter system  40  has a generally cylindrical shape, and the diameter thereof is essentially equal to the diameter of the tobacco rod  20 . The ends (i.e., upstream end  16  and downstream end  18 ) of the filter system  40  are open to permit the passage of air and smoke therethrough. 
     The filter system  40  includes at least one filtering material  42  circumscribed by a plug wrap  44 . The plug wrap  44  is a paper which optionally incorporates a carbonaceous material. The plug wrap  44  circumscribes the total length of the filter system  40 . The filter system  40  is attached to the tobacco rod  20  by a tipping material  50 , which preferably circumscribes both the entire length of the filter system  40  and an adjacent region of the tobacco rod  20 . The tipping material  50  is typically a paper like product; however, any suitable material can be used. The inner surface of the tipping material  50  is fixedly secured to the outer surface of the plug wrap  44  and the outer surface of the wrapping material  30  of the tobacco rod  20 , using a suitable adhesive. A ventilated or air diluted smoking article  10  can be provided with an air dilution means, such as a series of ventilation holes or perforations (not shown), each of which extend through the tipping material  50  and optionally the plug wrap  44 . 
       FIG. 2  shows a smoking article  10  in the form of a cigarette having at least one hollow tube  60  of a heat conductive material  68  within the cylindrical rod  20  of smoking material  21  and filter system  40 . As shown in  FIG. 2 , the filter system  40  preferably includes a first filtering material  74 , an adsorbent material  76 , and a second filtering material  78 . However, it can be appreciated that any suitable filter system  40  having at least one segment or plug of an adsorbent material  76  can be used. In use, the at least one hollow tube  60  provides a passageway leading from the hollow tube  60  of the cylindrical rod  20  of smoking material  21  through the adsorbent material  76  to within the second filtering material  78  of the filter system  40 . 
     The tobacco rod  20  as shown in  FIG. 2  is comprised of a smoking material  21  having at least one hollow tube  60  extending from within the tobacco rod  20  into the filter system  40 . The at least one hollow tube  60  can be a centrally positioned hollow tube  62  as shown in  FIG. 2 , a plurality of hollow tubes  64  as shown in  FIG. 3 , or a plurality of hollow fibers  66  as shown in  FIG. 4 . The at least one hollow tube  60  has a heat conductive wall  72  made of a heat conductive material  68 . During the smoking of the article  10 , the heat generated by the lit end  12  of the article is transferred to the heat conductive wall  72  of the hollow tube  60 ,  62 ,  64  or fibers  66 , which causes a flavorant material  80  retained within the at least one hollow tube  60 ,  62 ,  64  or fibers  66  to contribute to organoleptic attributes of mainstream smoke produced by the smoking article  10 . 
     As shown in  FIG. 2 , the at least one hollow tube  60  preferably extends from within the tobacco rod  20  through the first filtering material  74  and adsorbent material  76  into the second filtering material  78  of the filter system  40 . It can be appreciated, however, that the hollow tube  60  can be alternatively aligned with and abutting the second filtering material  78  rather than extending into the second filtering material  78  as shown in  FIG. 2 . Alternatively, the at least one hollow tube  60  can extend to any other suitable position within the smoking article  10 . In addition, it can be appreciated that the hollow tube  60  can extend from within the tobacco rod  20  as shown in  FIG. 2  or alternatively the hollow tube  60  can extend all the way to the lit end  12  of the smoking article  10 . If the hollow tube  60  extends to the lit end  12  of the smoking article  10 , a filler of loose tobacco or other suitable smoking material  21  can be placed within the hollow tube  60  to maintain the visual integrity (appearance) of the smoking article  10 . 
     The at least one hollow tube  60  also includes a flavorant material  80 , which is retained within the hollow tubes  60 ,  62 ,  64  or fibers  66 . The flavorant material  80  provides an added flavor or flavorant to the smoking article  10  during the smoking action. Accordingly, it is preferable that the hollow tube or fibers  60 ,  62 ,  64 ,  66  have an internal volume, which is adequate to retain sufficient flavorant materials  80  to provide desired taste attributes to mainstream smoke produced by the smoking article  10 . The at least one hollow tube  60  preferably has an internal diameter  70  in the range of about 0.1 mm to 5.0 mm (millimeters) and more preferably about 0.2 mm to about 2.0 mm. Alternatively, if the at least one hollow tube  60  is a bundle of hollow fibers  66 , the hollow fibers  66  can have an internal diameter  70  in the range of about 2 to about 100 μm (micrometers) and more preferably about 5 to about 50 μm. The tobacco rod  20  is preferably between 7.0 and 10.0 mm (millimeters) in diameter and 60 to 125 mm in length. However, it can be appreciated that the tobacco rod  20  can be any suitable diameter and length. 
     The heat conductive material  68 , which forms the heat conductive walls  72  of the hollow tubes and fibers  60 ,  62 ,  64 ,  66  also prevents the migration and penetration of the flavorant materials  80  into the smoking material  21  of the tobacco rod  20 . The walls  72  preferably have a thickness of about 0.1 μm (micrometers) to about 3.0 μm and more preferably about 0.2 μm to about 1.0 μm. It can be appreciated that the heat conductive material  68  is also chosen based on the heat conductive materials  68  ability to provide rapid heat conducting properties to transfer heat from the lit end  12  of the smoking article  10  to the walls  72  of the hollow tubes and fibers  60 ,  62 ,  64 ,  66 . Suitable heat conductive materials  68  for the hollow tubes and/or fibers  60 ,  62 ,  64 ,  66  can be graphite, any suitable metallic material or other suitable heat conducting material, which can be used in a smoking article  10 . 
     As shown in  FIG. 2 , the flavorant materials  80  are retained inside the hollow space of the hollow tubes  60 ,  62 ,  64  or fibers  66 . The flavorant materials  80  preferably extend the entire length of the hollow tube or fibers  60 ,  62 ,  64 ,  66 . However, it can be appreciated that in an alternative embodiment, the flavorant materials  80  can be located only within the tobacco rod  20  portion of the hollow tubes or fibers  60 ,  62 ,  64 ,  66 . In addition, the amount of flavorant materials  80  can vary depending on the desired aromas and specific flavorant materials  80 . 
     During smoking, the heat generated in the lit end  12  of the smoking article  10  is transferred to the heat conductive wall  72  of the hollow tubes  60 ,  62 ,  64  or fibers  66 . The heat from the heat conductive wall  72  causes the flavorant materials  80  retained inside the at least one hollow tube or fibers  60 ,  62 ,  64 ,  66  to generate a flavored aerosol or flavorant. The generated flavored aerosol or flavorant exits through the end  18  of the filter system  40  via the at least one hollow tube  60 ,  62 ,  64  or fibers  66  and the second filtering material  78 . As shown, the hollow tubes or fibers  60 ,  62 ,  64 ,  66  deliver the flavorant to the buccal (mouth-end) of the filter  18  by bypassing the adsorbent material  76  of the filter system  40 . Accordingly, the released flavored aerosol or flavorant is not subject to filtration adsorbtion from the adsorbent material  76 . 
     The flavorant materials  80  can include any suitable material that generates flavor upon heating. The heating of the flavorant materials  80  preferably releases the flavorant as a result of expansion, evaporation, distillation, decomposition or other suitable reaction to the heat from the walls  72  of the hollow tubes or fibers  60 ,  62 ,  64 ,  66 . The flavorant material  80  can be a single component or a multi-flavored component that is suitable for use in cigarette manufacturing such as menthol and vanillin. The flavorant materials  80  can also be an aroma of choice, such as peppermint, coconut, roasted, and/or toasted aromas. However, almost any flavor oil or composition can be used, such as having hydrophobic qualities. In addition, the concentration of flavorant materials  80 , within the hollow tube or fibers  60 ,  62 ,  64 ,  66  can be adjusted or modified to provide the desired amount of flavorant material  80 . Thus, the concentration of the flavorant materials  80 , within the hollow tubes or fibers  60 ,  62 ,  64 ,  66  can vary depending on the desired aroma. The flavorant materials  80  can alternatively be encapsulated within an outer shell wall  82  ( FIGS. 5 and 6 ) in the form of a capsule  84  having a suitable shell material such as cyclo-dextrine. It can be appreciated that any suitable shell material can be used for the encapsulation of the flavorant materials  80 . 
     In addition, it can be appreciated that each of the open ends of the tubes  60 ,  62 ,  64  or fibers  66  can be temporarily sealed with heat meltable materials  84  such as waxes, or water sensitive materials such as polyvinyl alcohol, starch, flour, cyclo-dextrine and sugar. The sealing of the hollow tubes  60 ,  62 ,  64 , or fibers  66  retain the flavorant material  80  within the tube  60 ,  62 ,  64  or fibers  66  and prevents the migration of the flavorant materials  80  through the open ends  86  of the hollow tubes  60 ,  62 ,  64  or fibers  66  to the tobacco rod  20  or filter system  40 . 
     Upon lighting of the smoking article  10 , the mainstream smoke is generated by and drawn from the tobacco rod  20  and through the filter system  40 . Herein, the “upstream” and “downstream” relative positions between filter materials  42  and other features are described in relation to the direction of mainstream smoke as it is drawn from the at least one hollow tube  60  of the tobacco rod  20  and through the multi-component filter system  40 . Preferably, the filter system  40  comprises a first, upstream filtering material  74 , an adsorbent material  76  and a second filtering material  78 . 
     The adsorbent material  76  is preferably downstream of the first filtering material  74  as shown in  FIGS. 2 and 3 . However, it can be appreciated that the adsorbent material  76  can be upstream of the first filtering material  74 , wherein the filter system has only one filtering material  74  rather than a first and second filtering material. The adsorbent material  76  is preferably a porous material such as an activated carbon, a zeolite, a silica gel or a polymer based adsorbent or other suitable adsorbent material. As shown in  FIG. 2 , the adsorbent material  76  is preferably surrounded on each side by a plug of filtering material  74 ,  78 . The filtering material  74 ,  78  is preferably cellulose acetate tow having a low resistance to draw (“RTD”). However, any suitable filtering material  74 ,  78  can be used. 
     For example, if the adsorbent material  76  is an activated carbon filter material, the activated carbon filter material can be in the form of granules and the like. In one embodiment, the activated carbon filter material is a high surface area, activated carbon such as a coconut shell based carbon of typical ASTM mesh size used in the cigarette filter manufacture. For example, the adsorbent material  76  can be a bed of activated carbon, which is adapted to adsorb constituents of mainstream smoke, particularly, those of the gas phase including aldehydes, ketones and other volatile organic compounds, and in particular 1, 3 butadiene, acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, toluene, styrene, acetaldehyde or hydrogen cyanide. With respect to the adsorbent materials  76  in the form of carbon particles  20 , it is preferred that the carbon particles have a mesh size of from 10 to 70, and more preferably a mesh size of 20 to 50. 
     When the cigarette or smoking article  10  is lit and a puff is drawn on the smoking article  10 , air flow in the cigarette or smoking article  10  takes place in two regions, one through an annular bed of smoking material  21  contained between the at least one hollow tube  60  and the outer cigarette wrapper  30 , and the other through the hollow tube  60 . As the smoking article  10  is smoked the heat from the burning tobacco material at the lit end of the smoking article heats the flavorant materials  80  within the hollow tube  60  releasing the flavorant to the smoker. Since the flavorants are contained within the hollow tube or fibers  60 ,  62 ,  64 ,  66  the flavorants are delivered without loss of flavor via filtration through the adsorbent material  76 . 
       FIG. 3  shows a smoking article  10  in the form of a cigarette having a plurality of hollow tubes  64  of heat conductive material  68  within the cylindrical rod  20  of smoking material  21  and the filter system  40 . As shown in  FIG. 3 , the plurality of hollow tubes  64  extends from within the tobacco rod  20  of smoking article to filter system  40 . The plurality of hollow tubes  64  extend entirely through the first filtering material  74  and adsorbent material  76  and partially into the second filtering material  78 . The plurality of hollow tubes  64  are preferably centrally positioned within the tobacco rod  20  and filter system  40 . However, it can be appreciated that any suitable configuration of the hollow tubes  64  within the tobacco rod  20  and filter system  40  can be used. 
       FIG. 4  shows a smoking article  10  in the form of a cigarette having a plurality of hollow fibers  66  of heat conductive material  68  within the cylindrical rod  20  of smoking material  21  and the filter system  40 . As shown in  FIG. 4 , the plurality of hollow fibers  66  extends from within the tobacco rod  20  of smoking article to filter system  40 . The hollow fibers  66  extend entirely through the first filtering material  74  and adsorbent material  76  and partially into the second filtering material  78 . The hollow fibers  66  are preferably centrally positioned within the tobacco rod  20  and filter system  40 . However, it can be appreciated that any suitable configuration of the hollow fibers  66  within the tobacco rod  20  and filter system  40  can be used. 
       FIG. 5  shows a cross sectional view of  FIG. 2  along the line A-A. As shown in  FIG. 5 , the smoking article  10  comprises at least one hollow tube  60  adapted to receive a flavorant material  80 . The at least one hollow tube  60  has a wall  72  comprising a heat conductive material  68 , such that during smoking of the article  10 , the heat generated in the lit end of the article  10  is transferred to the heat conductive wall  72  of the hollow tube, which causes the flavorant materials  80  to generate flavor by expansion, evaporation, distillation, decomposition or other suitable methods. 
       FIG. 6  shows a cross sectional view of  FIG. 3  along the line B-B. As shown in  FIG. 6 , instead of a hollow tube  62  as shown in  FIG. 5 , the at least one hollow tube  60  can include a plurality of hollow tubes  64  having flavorant materials  80  located therein. 
       FIG. 7  shows a cross sectional view of  FIG. 4  along the line C-C. As shown in  FIG. 7 , the hollow tube  60  is a plurality of hollow fibers  66 . The hollow fibers  66  preferably have an internal diameter  70  of about 5 to 50 μm (micrometers). 
     The hollow tube  60  and filter system  40  having an adsorbent material  76  as shown in  FIGS. 2-7  results in a smoking article  10  that lowers or reduces targeted smoke components, such as carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAH). The reduction in the targeted smoke components occurs as a result of the lower combustion temperature of the smoking material  21  from heat dispatching (transferring) from the hollow heat conductive tubes  60 ,  62 ,  64  and fibers  66 . In addition, by combining the hollow tubes  60 ,  62 ,  64  and fibers  66  having a heat conductive material  68 , a smoking article  10  or cigarette having reduced smoke constituents, can be produced which at the same time possess the original flavor of a full flavor cigarette. Specifically, by introducing the heat conducting hollow tube  60 ,  62 ,  64  and/or fibers  66  it can be appreciated that the smoking article  10  can lower the combustion temperature of the coal, so less carbon monoxide, polycyclic aromatic hydrocarbon and other targeted smoke constituents are generated during smoking of the smoking article  10 . 
     It will be understood that the foregoing description is of the preferred embodiments, and is, therefore, merely representative of the article and methods of manufacturing the same. It can be appreciated that variations and modifications of the different embodiments in light of the above teachings will be readily apparent to those skilled in the art. Accordingly, the exemplary embodiments, as well as alternative embodiments, may be made without departing from the spirit and scope of the articles and methods as set forth in the attached claims.