Patent Publication Number: US-2016219928-A1

Title: Smoking article having carbon dioxide delivery technology for sensorially improved carbon filtration and method of making

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 60/935,543, filed on Aug. 17, 2007, the entire content of which is incorporated herein by reference. 
    
    
     SUMMARY 
     Provided is a smoking article comprising tobacco, a filter and a charge of carbon dioxide gas. The charge of carbon dioxide gas provides at least about 10% more carbon dioxide on average for all puffs than a traditional cigarette so as to improve the taste of mainstream smoke. 
     Also provided is a method of making a cigarette having elevated levels of carbon dioxide in mainstream smoke. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a cigarette charged with carbon dioxide. 
         FIG. 2  is a graph comparing the carbon dioxide levels during the initial puffs of the smoking article charged with carbon dioxide of  FIG. 1  and a traditional cigarette 
         FIGS. 3A and 3B  are perspective views of preferred embodiments of a smoking article charged with carbon dioxide and including a carbon molecular sieve. 
         FIG. 4  is a graph showing the amount of carbon dioxide in the first puff of a smoking article based on the amount of carbon molecular sieve present in the smoking article and the amount of carbon dioxide on average in all puffs based on the amount of carbon molecular sieve present in the filter. 
         FIG. 5  is a graph showing the concentration of carbon dioxide in the first through seventh puffs of a smoking article including carbon on tow and a smoking article including carbon on tow, a carbon molecular sieve, and a charge of carbon dioxide. 
         FIG. 6  is a perspective view of a preferred embodiment of a smoking article having a filter including tubes containing carbon dioxide and a sorbent. 
         FIG. 7  is an illustration of the hollow tubes of  FIG. 6 . 
         FIG. 8  is a perspective view of a hollow tube shown in  FIGS. 6 and 7 . 
         FIG. 9  is front view of an embodiment of a package for containing the smoking articles of  FIGS. 1, 3 and 6 . 
         FIG. 10  is a top view of the package of  FIG. 9 . 
         FIG. 11  is a graph showing the effect of the carbon dioxide charge on smoke chemistry. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the term “smoking articles” is intended to include elongated smoking articles, such as cigarettes and cigars. Non-traditional cigarettes such as cigarettes for electrical smoking systems as described in commonly-assigned U.S. Pat. Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,526; 5,692,525; 5,666,976; 5,345,951; 4,991,606; 4,966,171 and 5,499,636, the disclosures of which are hereby incorporated by reference herein in their entireties, are also included in the definition of smoking articles or cigarettes generally. 
     As used herein, the term “traditional cigarette” describes filtered, preferably low tar, cigarettes including a sorbent that do not carry a carbon dioxide charge as described herein. 
     As used herein, the term “smoking” is intended to include the heating, combusting or otherwise causing release of mainstream smoke from tobacco. 
     As used herein, the term “mainstream” smoke refers to the mixture of gases passing down the smoking article and issuing through the filter end, e.g., the amount of smoke issuing or drawn from the mouth end of a cigarette during smoking of the cigarette. The mainstream smoke contains smoke that is drawn in through both the lighted region, as well as through the cigarette paper wrapper. The term “side stream” smoke refers to smoke produced during static burning. 
     As used herein, the term “initial puffs” refers to the first, second, third and/or fourth puffs taken after lighting and/or heating a cigarette or smoking article. 
     As used herein, the term “all puffs” refers to all puffs taken during the use of a smoking article. 
     As used herein, the term “sorption” includes filtration by absorption and/or adsorption. Sorption encompasses interactions on the outer surface of the sorbent, as well as interactions within the pores and channels of the sorbent. Sorption also describes the loading of carbon dioxide on a carbon molecular sieve. 
     As used herein, the term “sorbent” refers to a substance that can condense or hold molecules of other substances on its surface, and/or can take up other substances, i.e., through penetration of the other substances into its inner structure, or into its pores. Accordingly, the term “sorbent” as used herein refers to either an adsorbent, an absorbent, or a substance that can function as both an adsorbent and an absorbent. 
     As used herein, the term “remove” refers to adsorption and/or absorption of at least some portion of at least one constituent of mainstream smoke. 
     As used herein, the terms “carbon dioxide charge,” “charge of carbon dioxide,” and “charged” refers to the addition of and a supply of carbon dioxide in a smoking article component. The charge of carbon dioxide can be added by passing carbon dioxide through the smoking article and/or filter or by incorporating a carbon dioxide filled tube or other such container that sealingly retains carbon dioxide at ambient temperature and/or pressure within the filter. The terms “charge” and “charging” also refer to the act of passing carbon dioxide through and/or supplying carbon dioxide to the smoking article and/or filter. 
     Provided is a smoking article having a charge of carbon dioxide so as to increase the amount of carbon dioxide in mainstream smoke during smoking of the smoking article, thereby enhancing the flavor thereof. 
     The carbon dioxide provides a “mouthfeel” effect similar to that of a carbonated soda (in contrast to a flat soda), thereby improving the taste of the smoking article. In addition, carbon dioxide adsorbed on a carbon adsorbent can reduce the initial activity of the carbon adsorbent, due to the blocking of the smallest micropores, thereby preventing the removal of some aroma compounds. In theory, the loading of carbon dioxide on activated carbon and/or a carbon molecular sieve in a filter may reduce the “carbon taste” some American smokers associate with carbon filtration. 
     Preferably, the smoking article provides at least about 10% more carbon dioxide on average in all puffs than a traditional cigarette, and more preferably at least about 20% more carbon dioxide on average in all puffs, (e.g. at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%). Also preferably, the smoking article provides at least about 25% more carbon dioxide in the initial puffs as compared to a traditional cigarette. 
     As described herein and shown in  FIG. 1 , a smoking article  10  includes a filter  12 , a tobacco rod  14 , and a charge of carbon dioxide. Preferably, the filter  12  includes a first filter segment  16  and a sorbent  18 . Also preferably, the sorbent is in the form of carbon on tow (COT)  18 . In an embodiment, the sorbent is a carbon molecular sieve in the form of beads, granules, pellets, carbon molecular sieve on tow, and the like. The filter  12  is joined to the tobacco rod  14  by tipping paper  22 . 
     In an embodiment, as shown in  FIGS. 1, 3A and 3B , a ventilation zone 8 is established with a first row (and optionally second and possibly third rows) of ventilation holes through the tipping paper  22 . Preferably, the ventilation zone 8 achieves a ventilation level of the smoking article of at least 25% and more preferably at least 50% to 90%. 
     In a preferred embodiment, the charge of carbon dioxide can be introduced into the smoking article by attaching a smoking article to a gas line with a flexible rubber septa and then passing 100% carbon dioxide gas into and through the smoking article  10  and/or filter  12  for at least about one minute, and more preferably at least about 2 minutes, prior to packaging so as to provide a charge of carbon dioxide in the smoking article which increases the amount of carbon dioxide in mainstream smoke at least during the initial puffs of the smoking article. Preferably, about 0.05 liters per minute (L/min) to about 2.5 L/min, more preferably about 0.25 L/min to about 1.0 L/min of carbon dioxide is passed through the smoking article and/or filter. Preferably, the smoking article is placed in a sealed container immediately after charging the smoking article with carbon dioxide to thereby retain the elevated carbon dioxide level charged into the smoking article until release during smoking. 
     In a preferred embodiment, the carbon dioxide is stored on the carbon-on-tow filter material (COT) while in the sealed container to thereby avoid the carbon on tow releasing the carbon dioxide under atmospheric pressure and/or temperature conditions. 
       FIG. 2  is a graph comparing the carbon dioxide concentration of the initial puffs of the smoking article of  FIG. 1 , charged with carbon dioxide, and a traditional filtered smoking article when tested under Federal Trade Commission (FTC) conditions (35 cc per 2 seconds) on a standard smoking machine. As shown, the first and second puffs of the smoking article of  FIG. 1  have a higher concentration of carbon dioxide as compared to the traditional cigarette indicating better flavor in the first and second puffs. Despite the presence of the sorbent in the charged smoking article, which can act to remove flavor compounds, the carbon dioxide charge increases the amount of carbon dioxide at least in the initial puffs thereby enhancing the flavor of the initial puffs. 
     Exemplary sorbents for use in the filter  12  include molecular sieves such as zeolites (e.g. Type 4A, 13X, etc.), silicas, silicates (e.g. aluminosilicates), aluminas, carbon molecular sieves and/or carbons (e.g. activated carbon). Preferably, the filter includes about 30 mg to about 250 mg of the sorbent. 
     By “activated carbon” is meant any porous, high surface area form of carbon. Activated carbon can be derived via thermal treatment of any suitable carbon source. The activation treatment typically increases the porosity, and activated carbon can be provided with a wide range of pore sizes or the pore sizes can be controlled to provided a desired pore size distribution. 
     In a preferred embodiment, the activated carbon can be in the form of beads, granules, fibers, pellets, carbon on tow, carbon paper, and the like. 
     Preferably, activated carbon can have any desired pore size distribution that comprises pores such as micropores, mesopores and macropores. The term “microporous” generally refers to such materials having pore sizes of about 20 Angstroms or less while the term “mesoporous” generally refers to such materials with pore sizes of about 20 Angstroms to about 500 Angstroms. 
     Preferably, the activated carbon 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 and hydrogen cyanide. 
     Since a sorbent, such as activated carbon, may also absorb the flavor compounds, a charge of carbon dioxide is added to the filter to increase the amount of carbon dioxide in the initial puffs of the smoking article, thereby enhancing the flavor thereof. 
     In an embodiment, the sorbent is a carbon molecular sieve. Because a carbon molecular sieve has a smaller average pore size with a narrow distribution as compared to activated carbon, the carbon molecular sieve does not adsorb constituents of mainstream smoke as effectively as the activated carbon, but is suitable for adsorption and storage of small molecules such as carbon dioxide. 
     Examples of suitable types of tobacco materials that can be used in the tobacco rod  14  of the smoking article  10  include, but are not limited to, flue-cured tobacco, Burley tobacco, Maryland tobacco, Oriental tobacco, rare tobacco, specialty tobacco, blends thereof and the like. The tobacco material may be provided in any suitable form, including, but not limited to, tobacco lamina, processed tobacco materials, aged tobacco such as volume expanded or puffed tobacco, processed tobacco stems, such as cut-rolled or cut-puffed stems, reconstituted tobacco materials, blends thereof, and the like. Tobacco substitutes may also be used. 
     Preferably, the tobacco is normally used in the form of cut filler, i.e., in the form of shreds or strands cut into widths ranging from about 2 mm to about 1 mm or even about 0.5 mm. The lengths of the strands range from between about 5 mm to about 80 mm. An exemplary cigarette can include between about 300 mg and about 750 mg of tobacco, preferably around 550 mg for a standard cigarette. The cigarettes may further comprise one or more flavors, or suitable diluents (e.g., burn diluents, combustion modifying agents, coloring agents, binders, etc.). 
     Referring now to  FIG. 3A , in a preferred embodiment, the smoking article  10  includes a filter  12 , a tobacco rod  14 , and a carbon dioxide charge. Preferably, the filter includes a first filter segment  16 , located at the downstream end of the smoking article  10 , a first sorbent  18  and a second sorbent  25  that is capable of absorbing and retaining carbon dioxide prior to use, and also capable of releasing carbon dioxide due to the force of a puff. Also preferably, heating and/or burning the smoking article aids in the release of the carbon dioxide from the second sorbent. 
     To avoid release of carbon dioxide into the atmosphere, the smoking article  10  is preferably stored in a sealed container immediately after charging the smoking article  10  with carbon dioxide so as to maintain the carbon dioxide levels in the smoking article  10 . For example, a smoking article  10  left at atmospheric temperature and pressure for about 5 minutes loses about 40% of the carbon dioxide charge. Thus, in a preferred embodiment, the smoking article  10  is stored in a sealed container within 5 minutes of charging a sorbent in the smoking article with carbon dioxide, and more preferably within about 2 minutes to about 3 minutes of loading the sorbent with carbon dioxide. 
     Also preferably, the smoking article  10  remains in a sealed container until use. Preferably, the smoking article  10  is used within 1 minute to about 10 minutes of removing the smoking article  10  from the sealed container. Otherwise, the carbon dioxide loaded on the sorbent is released into the atmosphere. 
     In a preferred embodiment, the second sorbent  25  occupies a cavity between sections of the first sorbent  18 , which is preferably carbon on tow (COT) and/or a carbon molecular sieve in the form of beads, pellets, granules, carbon molecular sieve on tow and the like. Preferably, the smoking article  10  is charged with carbon dioxide prior to packaging so that the average carbon dioxide level at least in the initial puffs is higher than that of a traditional cigarette by at least about 10%. 
     In a preferred embodiment, the filter  12  is attached to the tobacco rod  14  by a tipping paper  22 , which preferably circumscribes both the entire length of the filter  12  and an adjacent region of the tobacco rod  14 . The tipping paper  22  is typically a paper like product; however, any suitable material can be used. 
     In an embodiment, the cavity holding the second sorbent  25  may be taped with an adhesive on overtipping paper  19  having low gas permeability to slow the release of the carbon dioxide charge from the second sorbent. The overtipping paper  19  circumscribes a portion of COT plugs  18  on either side of the cavity. Preferably, a ventilation zone 8 is upstream and/or downstream of the cavity, but does not overlap the cavity. 
     In a preferred embodiment, the second sorbent  25  includes a carbon molecular sieve material, such as high density carbon beads, granules, pellets, carbon molecular sieve-on-tow and the like, having an average particle size of about 1 mm, and fine micropores, such as the carbon molecular sieve available from SKC Inc. or the carbon molecular sieve described in U.S. Pat. No. 4,820,681, the entire content of which is incorporated herein by reference. In a preferred embodiment, the filter  14  includes at least about 20 mg of carbon molecular sieve, more preferably at least about 50 mg. 
     In an embodiment, as shown in  FIG. 3B , in addition to the first filter segment  16 , the filter may include an additional filter segment  11  upstream of the carbon molecular sieve  25 . Preferably, the first filter segment  16  and the optional upstream filter segment  11  are made of cellulose acetate tow having a low resistance to draw (“RTD”). However, any suitable filtering material can be used. 
     As shown in  FIG. 4 , a graph shows the carbon dioxide content in a first puff and the average carbon dioxide content in all puffs as a function of various amounts of carbon molecular sieve present in the filter. As shown, the amount of carbon dioxide released rises in relation to the amount of carbon molecular sieve present in the filter indicating that the carbon molecular sieve aids in retaining the carbon dioxide in the smoking article prior to use, but effectively releases the carbon dioxide due to the force of a puff. The inclusion of carbon molecular sieve in the filter results in a higher concentration of carbon dioxide in at least the initial puffs, and preferably for all puffs, which in turn improves the flavor thereof. 
     Not wishing to be bound by theory, the increase in carbon dioxide is believed to be due to the ability of the carbon molecular sieve to absorb the carbon dioxide when the smoking article is charged, and also to the ability of the carbon molecular sieve to release the carbon dioxide due to the force of a puff. In a preferred embodiment, the carbon molecular sieve material dried to less than about 2% water content is loaded with carbon dioxide under ambient temperature and pressure conditions. For example, a gram of carbon molecular sieve material can be loaded with 70 mg to 80 mg of carbon dioxide. 
     Referring now to  FIG. 5 , a cigarette including 90 mg of carbon on tow, 100 mg carbon molecular sieve and a carbon dioxide charge are smoked on a standard smoking machine under Federal Trade Commission (FTC) conditions (35 cc per 2 seconds) and compared to a traditional cigarette containing 120 mg of carbon on tow and not charged with carbon dioxide. As shown, the carbon dioxide levels of the initial puffs are higher for the cigarette containing 100 mg carbon molecular sieve and charged with carbon dioxide indicating enhanced flavor in the initial puffs. 
     Referring now to  FIG. 6 , in a preferred embodiment, a smoking article  10  in the form of a cigarette includes a filter  12 , a tobacco rod  14 , and a carbon dioxide charge. Preferably, the filter  12  includes a first sorbent  18  and a second sorbent  25  that is capable of absorbing and retaining carbon dioxide prior to use, and also capable of releasing the carbon dioxide when a puff is taken. Preferably, the second sorbent  25  and the charge of carbon dioxide are contained in at least one hollow tube  30 . In an embodiment, a charge of carbon dioxide may also be contained in the first sorbent  18 . In a preferred embodiment, the first sorbent  18  is in the form of carbon on tow that surrounds the one or more hollow tubes  30 . 
     In a preferred embodiment, the hollow tube  30  is a permeable, semi-permeable, and/or impermeable tube  30  within the filter  12 . Preferably, each of the one or more hollow tubes  30  is sealed by a seal  31  (shown in  FIG. 8 ) that breaks due to the force of a puff. In a preferred embodiment, the seal  31  is preferably used to immobilize the contents of the hollow tubes  30 , and thus reduce dissipation of the charge of carbon dioxide and/or the carbon molecular sieve until the seal  31  is broken, ruptured, or perforated. 
     Preferably, the seal  31  is a frangible material, such as a polymer, which is capable of both sealing the hollow tube  30 , as well as breaking, rupturing, and/or perforating on demand. Preferably, the seal  31  is designed to break when smoke is drawn through the filter. Also preferably, the seal  31  is made of sugar or pectin, which can also be provided to flavor filtrate, such as smoke filtrate, contacting the seal  31  if desired. A single seal  31  can be used to seal the downstream ends of multiple tubes  30  and another single seal  31  can be used to seal upstream ends of the tubes  30 , as shown in  FIG. 8 . 
     Preferably, the hollow tubes  30  are oriented in a direction in which smokes travels through the smoking article so that the smoke can pass through the lumens of the tubes  30  to contact the sorbent  25  and release the charge of carbon dioxide contained therein. 
     As shown in  FIG. 7 , in an embodiment, the hollow tubes  30  are approximately parallel to one another in order to allow the smoke to evenly penetrate the hollow tubes  30 . 
     Preferably, the hollow tubes  30  are sized to a length less than the length of the filter  12  so that the entire length of each of the hollow tubes  30  can fit within the area of the filter  12  as the hollow tubes  30  are aligned in the direction of the smoke flow. 
     Also preferably, the inner diameter of the hollow tubes  30  is about 0.5 mm to about 3.0 mm. In a preferred embodiment, the filter  12  includes 1 to 10 hollow tubes  30  (e.g., 1 to 3, 3 to 5, 5 to 7 or 7 to 10). 
     In a preferred embodiment, the hollow tube  30  is charged by first sealing the second sorbent  25  in the tube  30  and then charging the tube  30  and the second sorbent  25  with carbon dioxide through a slow diffusion process. Preferably, most of the charge of carbon dioxide will be absorbed by the second sorbent  25 , and the remainder of the charge will fill the tube  30 . In another embodiment, the tubes  30  containing the second sorbent  25  are charged with carbon dioxide and then sealed with a seal  31  in a carbon dioxide atmosphere. 
     Smoking articles having carbon dioxide in one or more sealed tubes or other sealed arrangement can be packaged with conventional packaging materials. 
     In an embodiment, a smoking article  10  charged with carbon dioxide is placed in a sealed container, such as the container shown in  FIGS. 9 and 10 . Preferably, the container  50  has multiple compartments  52 , each sized and configured to hold and sealingly retain one smoking article  10  therein. In a preferred embodiment, flavorants can be inserted into the compartments  52  of the container. In an embodiment, each compartment  52  may be charged with carbon dioxide prior to sealing a smoking article  10  including a first and/or second sorbent therein. Preferably, each compartment  52  is charged with 100% carbon dioxide gas. Preferably, a seal  65  contains the smoking article and/or carbon dioxide charge within each compartment  52 . 
     In an embodiment, each smoking article  10  can be individually wrapped and/or inserted in a conventional cigarette pack. 
     Table 1 shows the effect of the addition of a carbon molecular sieve on ventilation (VENT), resistance to draw (RTD), and total particulate matter (TPM), as well as the average amount of carbon dioxide in all puffs of a smoking article, as compared to a cigarette containing 120 mg COT. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 Average 
                   
               
               
                   
                   
                 RTD, 
                 TPM, 
                 CO2, 
                 CO2 delivery 
               
               
                 Sample 
                 Vent, % 
                 mm 
                 mg 
                 % vol 
                 increase, % 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Cigarette 
                 48 
                 113 
                 5.7 
                 3.9 
                 — 
               
               
                 containing 
               
               
                 120 mg 
               
               
                 COT only 
               
               
                 Cigarette 
                 44 
                 120 
                 6.5 
                 6.9 
                 77 (increase as 
               
               
                 containing 90 mg 
                   
                   
                   
                   
                 compared to the 
               
               
                 COT and 100 mg 
                   
                   
                   
                   
                 cigarette 
               
               
                 carbon molecular 
                   
                   
                   
                   
                 containing 120 mg 
               
               
                 sieve and charged 
                   
                   
                   
                   
                 COT only) 
               
               
                 with carbon 
               
               
                 dioxide 
               
               
                   
               
            
           
         
       
     
     As shown in Table 1, the delivery of carbon dioxide per cigarette containing 90 mg carbon on tow and 100 mg of carbon dioxide charged carbon molecular sieve increased about 77% on average for all puffs as compared to a cigarette including only 120 mg carbon on tow. In addition, the ventilation and RTD is similar to that of the cigarette not including the carbon molecular sieve, suggesting that the carbon molecular sieve does not significantly affect smoke chemistry, but does enhance the delivery of carbon dioxide. 
     In addition, as shown in  FIG. 11 , the addition of the carbon molecular sieve resulted in the reduction of more gas constituents as compared to traditional cigarettes including 120 mg of carbon on tow. For example, the presence of the carbon molecular sieve reduces the amount of acetaldehyde, isoprene, and carbonyl sulfide despite the inability of carbon molecular sieve to adsorb constituents of mainstream smoke as effectively as activated carbon. 
     Also provided herein is a method of making a smoking article having increased carbon dioxide delivery technology so as to improve the taste of the initial puffs. 
     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.