Filter including electrostatically charged fiber material

Abstract

Provided is a cigarette filter and method for potentially reducing particle breakthrough. The filter includes an adsorbent including adsorbent particles dispersed within the filter and a plug of electrostatically charged fibers. Preferably, the adsorbent is activated carbon. In a preferred embodiment, the electrostatically charged fiber material is located downstream of the activated carbon. Preferably, the electrostatically charged fiber material has permanent electrostatic charges that electrostatically capture the carbon particles to reduce carbon particle breakthrough. In an embodiment, the electrostatically charged fiber material is randomly-oriented so as to mechanically capture particles entrained in mainstream smoke.

1 . A filter assembly for a smoking article comprising:
 an adsorbent including smoke entrainable adsorbent particles contained within a filter; and   a plug of electrostatically charged fiber material downstream of the adsorbent,   wherein said plug of electrostatically charged fiber material provides reduced adsorbent particle breakthrough.   
   
   
       2 . The filter assembly of  claim 1 , wherein said plug of electrostatically charged fiber material is located immediately downstream of said adsorbent. 
   
   
       3 . The filter assembly of  claim 1 , wherein said plug of electrostatically charged fiber material contains about 25 mg to about 75 mg of electrostatically charged fiber material. 
   
   
       4 . The filter assembly of  claim 1 , wherein said plug of electrostatically charged fiber material includes randomly-oriented electrostatically charged fiber material and/or axially oriented electrostatically charged fiber material. 
   
   
       5 . The filter assembly of  claim 1 , wherein said filter assembly contains about 30 mg to about 200 mg of said adsorbent. 
   
   
       6 . The filter assembly of  claim 1 , wherein said adsorbent comprises carbon on tow filter material, carbon paper, and/or a bed of loose carbon beads, granules, particles, and the like in a cavity of the filter. 
   
   
       7 . The filter assembly of  claim 1 , wherein said filter assembly is a plug-space-plug filter, and wherein said adsorbent includes activated carbon located in the space and the plug of electrostatically charged fiber material includes randomly-oriented and/or axially oriented electrostatically charged fiber material incorporated in the downstream plug of the plug-space-plug filter. 
   
   
       8 . The filter assembly of  claim 1 , wherein said adsorbent includes at least one flavorant. 
   
   
       9 . The filter assembly of  claim 1 , wherein said smoke entrainable adsorbent particles range in size from about 0.1 microns to about 10 microns. 
   
   
       10 . The filter assembly of  claim 1 , wherein said plug of electrostatically charged fiber material includes electret fibers and/or wherein said electrostatically charged fiber material is about 2.5 denier to about 8.0 denier. 
   
   
       11 . The filter assembly of  claim 10 , wherein said plug of electrostatically charged fiber material mechanically and/or electrostatically captures said adsorbent particles to reduce adsorbent particle breakthrough. 
   
   
       12 . The filter assembly of  claim 1 , further including a plug of axially-oriented cellulose acetate fibers upstream and/or downstream of said adsorbent. 
   
   
       13 . A cigarette comprising the filter assembly of  claim 1  attached to a tobacco rod, wherein an outer surface of said plug including electrostatically charged fiber material is in contact with tipping paper attaching the filter assembly to the tobacco rod. 
   
   
       14 . A smoking article comprising:
 a tobacco rod; and   a filter assembly including an adsorbent including smoke entrainable adsorbent particles and a plug of electrostatically charged fiber material,   wherein said plug of electrostatically charged fiber material provides reduced breakthrough of said particles.   
   
   
       15 . The smoking article of  claim 14 , wherein said plug of electrostatically charged fiber material is located downstream of said adsorbent in the filter assembly. 
   
   
       16 . The smoking article of  claim 14 , said smoke entrainable adsorbent particles range in size from about 0.1 microns to about 10 microns. 
   
   
       17 . The smoking article of  claim 14 , wherein said adsorbent is included in said smoking article in an amount of about 30 mg to about 200 mg. 
   
   
       18 . The smoking article of  claim 14 , wherein said filter assembly contains about 25 mg to about 70 mg of electrostatically charged fiber material. 
   
   
       19 . The smoking article of  claim 14 , wherein said adsorbent comprises carbon on tow filter material, carbon paper, and/or a bed of loose carbon beads, granules, particles, and the like in a cavity of the filter. 
   
   
       20 . The smoking article of  claim 14 , wherein said filter assembly further includes one or more plugs of cellulose acetate fibers upstream and/or downstream of said adsorbent. 
   
   
       21 . A method of making a filter rod for a smoking article comprising:
 placing 2-up plugs of filter material in spaced apart relationship;   placing plugs of electrostatically charged fiber material between the 2-up plugs such that cavities are formed at upstream and downstream ends of every other 2-up plug;   placing an adsorbent in the cavities; and   cutting said plugs of filter material centrally to form 2-up filter assemblies.   
   
   
       22 . The method of  claim 21 , further including attaching a tobacco rod to each of said 2-up filter assemblies. 
   
   
       23 . The method of  claim 21 , further including cutting said 2-up filter assemblies centrally to form complete cigarettes. 
   
   
       24 . A method of treating mainstream tobacco smoke, comprising:
 drawing mainstream smoke through a smoking article;   during said drawing step, contacting said mainstream tobacco smoke with an adsorbent; and   subsequent to said contacting step, contacting said mainstream tobacco smoke with an electrostatically charged fiber.