Cigarette filter

Abstract

A cigarette filter that includes a multiple section filter which reduces the level of predetermined smoke constituents. The filter ( 130 ) consists of a fibrous filter plug ( 132 ) located at the mouth-end of the cigarette, a section ( 136 ) containing a selective adsorbent material, and a section ( 134 ) containing a general adsorbent material. The selective adsorbent material, such as a phenol-formaldchyde resin matrix surface-functionalized with mainly primary and secondary amine functional groups, removes specific smoke constituents from the tobacco smoke. The general adsorbent material, such as activated charcoal, is preferably capable of adsorbing a range of chemical compounds without a high degree of specificity. Structurally, the fibrous filter plug, the selective adsorbent section, and the general adsorbent section are co-axially aligned it tandem.

1 . A multiple section cigarette filter comprising: 
 (a) a selective adsorbent section comprising a selective adsorbent material having an affinity for a predetermined class of chemical compounds dispersed throughout a fibrous material; and    (b) a general adsorbent section comprising a general adsorbent material having a high surface area and being capable of adsorbing smoke constituents without a high degree of specificity, said selective adsorbent section, and said general adsorbent section being axially aligned in tandem.    
     
     
         2 . The cigarette filter of  claim 1  wherein said selective adsorbent material is an ion-exchange resin.  
     
     
         3 . The cigarette filter of  claim 2  wherein said selective adsorbent material has a surface area sufficient to ensure that the surface functional sites are easily accessible to a smoke constituent.  
     
     
         4 . The cigarette filter of  claim 2  wherein said ion-exchange resin has a phenol-formaldehyde resin matrix and is surface-functionalized with primary and secondary amine groups.  
     
     
         5 . The cigarette filter of  claim 2  wherein said selective adsorbent section comprises said selective adsorbent material dispersed throughout a fibrous material.  
     
     
         6 . The cigarette filter of  claim 2  wherein said selective adsorbent section comprises a close-packed bed of said selective adsorbent material.  
     
     
         7 . The cigarette filter of  claim 1  wherein said general adsorbent material is selected from the group consisting of activated charcoal, activated coconut carbon, activated coal-based carbon, zeolite, silica gel, meerschaum, aluminum oxide, a coal-based charcoal made from semi-anthracite coal, a carbonaceous resin derived from the pyrolysis of sulfonated styrene-divinylbenzene, or combinations thereof.  
     
     
         8 . The cigarette filter of  claim 7  wherein said general adsorbent section comprises said general adsorbent material dispersed throughout a fibrous material.  
     
     
         9 . The cigarette filter of  claim 7  wherein said general adsorbent section comprises a close-packed bed of said general adsorbent material.  
     
     
         10 . The cigarette filter of  claim 7  wherein said general adsorbent section further includes a metal oxide or other metal-based complex.  
     
     
         11 . The cigarette filter of  claim 1  including a fibrous filter plug wherein said filter plug is made from cellulose, cellulose acetate tow, paper, cotton, polypropylene web, polypropylene tow, polyester web, polyester tow or a combination thereof, said fibrous filter plug being co-axially aligned in tandem with said selective adsorbent section and said general adsorbent section.  
     
     
         12 . The cigarette filter of  claim 11  wherein said filter plug further includes a plasticizer, a liquid additive, a flavoring agent or a combination thereof.  
     
     
         13 . The cigarette filter of  claim 11  wherein said general adsorbent section is positioned between said fibrous filter plug and said selective adsorbent section.  
     
     
         14 . The cigarette filter of  claim 11  wherein said selective adsorbent section is positioned between said fibrous filter plug and said general adsorbent section.  
     
     
         15 . The cigarette filter of  claim 11 , said fibrous filter plug being positioned between said selective adsorbent section and said general adsorbent section.  
     
     
         16 . The cigarette filter of  claim 1 , including a plug wrap circumscribing said general adsorbent section and said selective adsorbent section.  
     
     
         17 . The cigarette filter of  claim 1 , said selective absorbent material having a surface area greater than about 35 m 2 /g.  
     
     
         18 . A multiple section cigarette filter comprising: 
 (a) a fibrous filter plug selected from the group consisting of cellulose, cellulose acetate tow, paper, cotton, polypropylene web, polypropylene tow, polyester web, polyester tow or a combination thereof;    (b) a selective adsorbent section comprising an ion-exchange resin having a surface area sufficient to ensure that the surface functional sites are easily accessible to a smoke constituent; and    (c) a general adsorbent section comprising a general adsorbent material selected from the group consisting of activated charcoal, activated coconut carbon, activated coal-based carbon, zeolite, silica gel, meerschaum, aluminum oxide, a coal-based charcoal made from semi-anthracite coal, a carbonaceous resin derived from the pyrolysis of sulfonated styrene-divinylbenzene, or combinations thereof, said fibrous filter plug, said selective adsorbent section, and said general adsorbent section being axially aligned in tandem.    
     
     
         19 . The cigarette filter of  claim 18  wherein said ion-exchange resin has a phenol-formaldehyde resin matrix and is surface-functionalized with primary and secondary amine groups.  
     
     
         20 . The cigarette filter of  claim 18  wherein said selective adsorbent section comprises said ion-exchange resin dispersed throughout a fibrous material.  
     
     
         21 . The cigarette filter of  claim 18  wherein said selective adsorbent section comprises a close-packed bed of said ion-exchange resin.  
     
     
         22 . The cigarette filter of  claim 18  wherein said general adsorbent section comprises said general adsorbent material dispersed throughout a fibrous material.  
     
     
         23 . The cigarette filter of  claim 22  wherein said general adsorbent section further includes an additive selected from a metal oxide or other metal-based complex.  
     
     
         24 . The cigarette filter of  claim 18  wherein said general adsorbent section comprises a close-packed bed of said general adsorbent material.  
     
     
         25 . The cigarette filter of  claim 24  wherein said general adsorbent section further includes an additive selected from a metal oxide or a metal-based complex.  
     
     
         26 . The cigarette filter of  claim 18  wherein said filter plug is made from cellulose acetate tow.  
     
     
         27 . The cigarette filter of  claim 18  wherein said filter plug further includes a plasticizer, a liquid additive, a flavoring agent or a combination thereof.  
     
     
         28 . The cigarette filter of  claim 18  wherein said general adsorbent section is positioned between said fibrous filter plug and said selective adsorbent section.  
     
     
         29 . The cigarette filter of  claim 18  wherein said selective adsorbent section is positioned between said fibrous filter plug and said general adsorbent section.  
     
     
         30 . The cigarette filter of  claim 18 , said fibrous filter plug being positioned between said selection absorbent section and said general absorbent section.  
     
     
         31 . The cigarette filter of  claim 18 , said selective absorbent material having a surface area greater than 35 m 2 /g.