Abstract:
A cigarette of an electrical smoking system includes a filter tipping including a web including added filtering material and a tubular wrapper around the web, and a tobacco rod portion adapted to generate a puff of smoke upon being heated by one or more heating elements during smoking, the tobacco rod portion being attached to the filter tipping.

Description:
BACKGROUND  
       [0001]     In cigarettes of the type used in electrical smoking systems such as are disclosed in commonly owned U.S. Pat. Nos. 5,388,594; 5,692,525; 6,209,547; 6,289,898; 6,615,840 and 6,888,313, and in U.S. Application Publication No. 20030131859, which patents and application publications are incorporated by reference in their entirety, it is generally desirable to duplicate aspects of the experience of smoking a regular cigarette, such as resistance to draw. However, the manner in which smoke is generated and air is drawn through the cigarette for the electrical smoking system is quite different from the way smoke is generated and air is drawn through a regular cigarette because of the vastly different physical structure of the smoking system versus the regular cigarette. It is desirable to provide cigarettes for use in electrical smoking systems having features that facilitate simulating the experience of smoking a regular cigarette.  
       SUMMARY  
       [0002]     According to one embodiment, a cigarette for an electrical smoking system includes a filter tipping including a web including added filtering material and a tubular wrapper around the web, and a tobacco rod portion adapted to generate a puff of smoke upon being heated by at least one heating element during smoking, the tobacco rod portion being attached to the filter tipping.  
         [0003]     According to another embodiment, a method for making a cigarette for an electrical smoking system includes making a filter tipping by surrounding a web including added filtering material with a tubular wrapper, and attaching a tobacco rod portion adapted to generate a puff of smoke upon being heated by at least one heating element during smoking to the filter tipping. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]      FIGS. 1A-1C  are cross-sectional side views of cigarettes according to various embodiments.  
         [0005]      FIGS. 2A-2C  show end views of a cigarette filter according to various embodiments.  
         [0006]      FIG. 3  shows a web having a three-dimensional shape being compressed and surrounded by a wrapper according to an embodiment.  
         [0007]      FIG. 4  shows a cigarette filter that uses multiple webs according to an embodiment. 
     
    
     DETAILED DESCRIPTION  
       [0008]     Cigarettes  21   a - 21   c  according to embodiments are shown in  FIGS. 1A-1C . The cigarettes all include a cigarette filter  23  including a web  25  including filtering material and a tubular wrapper  27  around the web. The cigarette  21  includes a cylindrical member, e.g., a tobacco containing rod portion  37   a - 37   c , for generating smoke attached to the cigarette filter. The cigarette  21  is of the type usable in an electrical smoking system such as is disclosed in commonly owned U.S. Pat. Nos. 5,388,594; 5,692,525; 6,209,547; 6,289,898; 6,615,840 and 6,888,313, and in U.S. Application Publication No. 20030131859, which patents and application publications are incorporated by reference in their entirety.  
         [0009]     The cigarette filter  23  can replace or be used together with a free flow filter. Several possible, non-limiting arrangements of components are shown in  FIGS. 1A-1C .  FIG. 1A  shows a cigarette  21   a  wherein a filter  23  is disposed in a filter tipping  33   a  including the filter  23  positioned adjacent a filter plug  35 , which can be, for example, a conventional cellulose acetate tow filter. A tobacco rod portion  37   a  is attached to the tipping  33   a  and includes a free flow filter  39 , a void  41  or open space, and a tobacco plug  43  wrapped in a wrapper  45  that may include a tobacco web, although other arrangements can also be used. In the electrical smoking system, heat is applied to the wrapper  45  to heat tobacco (e.g., the tobacco web and the tobacco plug  43 ) during puffing of the cigarette to thereby generate smoke. In addition to removing targeted constituents from smoke, using the filter  23  instead of or in addition to conventional tubular free-flow filters can facilitate adjustment of features of the cigarette such as resistance to draw (RTD) which can be useful in simulating the experience of smoking a traditional, lit-end cigarette.  
         [0010]      FIG. 1B  shows a cigarette  21   b  with a tipping  33   b  and tobacco rod portion  37   b  wherein the free flow filter  39  from the cigarette  21   a  is eliminated.  FIG. 1C  shows a cigarette  21   c  with a tobacco rod portion  37   c  wherein the filter  23  is used together with a free flow filter  47  in the tipping  33   c  between the filter  23  and the filter plug  35 . The foregoing are only several illustrative ones of numerous possible variations. There may be voids, free flow filters, filter plugs, tobacco plugs, and any other desired structures in the cigarette.  
         [0011]     In the cigarette filter  23 , the web  25  may include paper. The web  25  may include a coated paper, an impregnated paper, carbon paper, a laminate, or a laminate including paper. The web  25  may be formed into a non-planar shape, such as by folding or rolling or bending the web. As seen in  FIG. 2A , the web  25  may be formed into an accordian shape. As seen in  FIG. 2B , an accordian-shaped web  25  may be formed into a circular shape. As seen in  FIG. 2C , the web  25  may be crimped and formed into any one of numerous possible shapes. As seen in  FIG. 3 , the web  25  may be formed into any desired three-dimensional shape by a suitable forming apparatus  101  and then swaged or otherwise processed by a suitable compressing apparatus  103  to compress the shape. The web  25  may exert a force on the wrapper  27  to assist in maintaining a three-dimensional shape for the filter  23 . The wrapper  27  may be made from a web but may be formed from any structure suited for providing an outer covering for the web  25 , such as a pre-formed tube.  
         [0012]     The filtering material is any suitable material, such as a material that reacts with at least one constituent of cigarette smoke. The filtering material can include an aminopropylsilyl group covalently bonded to a non-volatile inorganic substrate. See, for example, commonly-owned U.S. Pat. Nos. 6,209,547, 6,584,979, and 6,595,218, which are hereby incorporated by reference. The aminopropylsilyl group is preferably a 3-aminopropylsilyl group. The substrate is preferably silica gel or molecular sieve material. The material may be provided on a web  25  of paper or other suitable material.  
         [0013]     In accordance with an embodiment, the physical and chemical properties of the filler material used to produce webs  25  of paper for making filters  23  are chosen and utilized to reduce the aldehyde content of the smoke produced during combustion/pyrolysis of the smoking article. The paper filler includes an ammonium-containing compound, which when heated evolves ammonia, which may chemically react with aldehydes in tobacco smoke and/or modify the combustion/pyrolysis reactions thereby reducing the initial formation of aldehydes, thereby decreasing the delivery of such aldehydes to a smoker. The filtering material can be an ammonium containing compound filler used in the web. See, for example, commonly-owned U.S. Pat. Nos. 6,289,898 and 6,615,840, which are incorporated by reference.  
         [0014]     A suitable ammonium-containing compound is an inorganic ammonium metal salt, such as an ammonium-alkaline earth metal salt, such as MgNH 4  PO 4 .xH 2 O, wherein x ranges from 1 to 6 (AMP). It is preferred that the ammonium-containing compound have a low solubility in water so as to be compatible with conventional papermaking processes, e.g., the filler is substantially insoluble in an aqueous dispersion containing ingredients of the paper, such as flax, etc. That is, the ammonium-containing compound should be stable enough in a papermaking process to survive intact as filler in the final paper product. This includes sufficient thermal stability to survive the drying steps in the papermaking process. Magnesium ammonium phosphate and its hydrates are well-suited to conventional papermaking processes, and evolve ammonia during the smoking process in a manner that greatly decreases the content of certain low molecular weight aldehydes in smoke. Magnesium potassium phosphate is isostructural with magnesium ammonium phosphate and can form solid solutions therewith effective for reducing the aldehyde content in smoke. An ammonium magnesium phosphate filler that consists essentially of the monohydrate form of magnesium ammonium phosphate is especially preferred.  
         [0015]     The ammonium-containing compound filler can also comprise one or more of the following mineral phases: dittmarite, struvite, hannayite, schertelite, mundrabillaite and swaknoite.  
         [0016]     Ammonium-containing compounds considered useful as filler materials have a range of surface areas, a range of particle sizes (mostly in the micron range), possess appropriate opacity, have low solubility in water (required for papermaking), and possess other properties that are considered desirable in fillers for papers used in cigarettes. In similar papers used for cigarette papers, the filler preferably has a particle size below 25 μm, more preferably below 10 μm.  
         [0017]     The filtering material can include nanoparticles. Some or all of the nanoparticles can be a filler used in the web and some or all of the nanoparticles can be disposed on a surface of the web. The nanoparticles can be capable of acting as at least one of an oxidant for converting carbon monoxide to carbon dioxide and a catalyst for converting carbon monoxide to carbon dioxide, or both. The nanoparticles can be selected from the group consisting of metals, metal compounds, metal oxides, doped metal oxides, and mixtures thereof. Suitable nanoparticles are preferably selected from the group consisting of Fe 2 O 3 , CuO, TiO 2 , CeO 2 , Ce 2 O 3 , Al 2 O 3 , Y 2 O 3  doped with zirconium, Mn 2 O 3  doped with palladium, and mixtures thereof. See, for example, commonly-owned U.S. Pat. No. 6,769,437 and U.S. Published Patent Application Nos. 20030075193 and 20030131859.  
         [0018]     The nanoparticles preferably have an average particle size less than about 500 nm, preferably an average particle size less than about 100 nm, more preferably an average particle size less than about 50 nm, and still more preferably an average particle size less than about 5 nm. The nanoparticles preferably have a surface area of at least about 20 m 2 /g, and more preferably a surface area of at least about 200 m 2 /g.  
         [0019]     Though embodiments have been described in conjunction with a single web  25 , it will be appreciated that multiple webs  25  may be used, as seen in  FIG. 4 . Also, more than one type of filtering material may be used on a single web or on different webs. In other embodiments (not shown) the filter may be disposed in the tobacco rod portion or in the tobacco rod portion and the tipping. Where multiple webs are used, they may occupy substantially the same volume, such as where they are layered next to one another, or may be arranged at different axial locations along the length of the cigarette that may be next to one another or not, as desired or necessary.  
         [0020]     While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.