Silica resin filter for smoking articles

Abstract

A smoking article capable of delivering a regulated smoke composition to a smoker, includes a combustible filler wrapped in a combustible sheath and a filter unit designed to remove components from the smoke, disposed within the sheath. The filter unit includes a mass of porous silica or resin particles, where the porous silica or resin particles have an average particle size of from about 35 to about 400 μm and preferably an average porosity of from about 10 Å to about 1000 Å. The porous cigarette filter is self-compensating with respect to air ventilation.

What is claimed is:  
     
         1 . A smoking article capable of delivering a regulated smoke composition to a smoker, comprising: 
 a) a combustible filler wrapped in a combustible sheath; and    b) a filter unit designed to remove components from said smoke disposed within said sheath, said filter unit comprising a mass of porous silica or resin particles,    wherein said porous silica or resin particles have an average particle size of from about 35 to about 400 μm.    
     
     
         2 . The smoking article of  claim 1 , wherein the filter unit is adjacent said combustible filler.  
     
     
         3 . The smoking article of  claim 1 , wherein the porous silica or resin particles have chemically bonded to their surfaces functional groups that exhibit preferential affinity for said components and that reversibly bind said components to elute components having a lower affinity than a previously bound component.  
     
     
         4 . The smoking article of  claim 3 , wherein the functional groups are bonded to the porous silica or resin particles by one of (i) direct bonding to surface atoms of the silica or resin particles, (ii) ester bonded to surface hydroxyl groups of the silica or resin particles, and (iii) bonded to the silica or resin particles by treatment of the silica or resin particles with an organosilane.  
     
     
         5 . The smoking article of  claim 3 , wherein the functional groups have the general formula:  
       R 1 (CH 2 ) n — wherein: 
 n is an integer from 1 to 40; and  
 R 1  is hydrogen, hydroxy, amine, amide, cyano, nitrile, nitro, thio, sulfide, sulfone, sulfoxide, I, Br, Cl, F, or an alkyl or aryl group of from 1 to 40 carbon atoms which may be straight or branched, saturated or unsaturated and is optionally substituted with one or more atoms selected from the group consisting of O, N, S, I, Br, Cl and F.  
   
     
     
         6 . The smoking article of  claim 1 , wherein the porous silica or resin particles have an average particle size of from about 40 to about 200 μm.  
     
     
         7 . The smoking article of  claim 1 , wherein the porous silica or resin particles have an average particle size of from about 35 to about 80 μm.  
     
     
         8 . The smoking article of  claim 1 , wherein said porous silica or resin particles have an average porosity of from about 10 Å to about 1000 Å.  
     
     
         9 . The smoking article of  claim 1 , wherein the porous silica or resin particles have an average porosity of from about 50 Å to about 1000 Å.  
     
     
         10 . The smoking article of  claim 1 , wherein the porous silica or resin particles have an average porosity of from about 60 Å to about 1000 Å.  
     
     
         11 . The smoking article of  claim 1 , wherein the porous silica or resin particles have an average porosity of from about 150 Å to about 500 Å.  
     
     
         12 . The smoking article of  claim 1 , wherein the porous silica or resin particles are selected from the group consisting of polymeric materials, silica based materials, composites of polymeric materials and silica based materials, and mixtures thereof.  
     
     
         13 . The smoking article of  claim 1 , wherein the porous silica or resin particles are selected from the group consisting of methacrylate, methyl methacrylate, ethylmethacrylate, styrene, styrene divinylbenzene, silica, magnesium silicate, ceramic, porous glass, and composite resins of silica and polymeric materials.  
     
     
         14 . The smoking article of  claim 1 , wherein the porous silica or resin particles are porous silica beads.  
     
     
         15 . The smoking article of  claim 1 , wherein the porous silica or resin particles form a packed column having a hollow space of at least 45%.  
     
     
         16 . The smoking article of  claim 1 , wherein the porous silica or resin particles form a packed column having a hollow space of at least 67%.  
     
     
         17 . The smoking article of  claim 1 , wherein the filter unit has an efficiency of about 50% or more.  
     
     
         18 . The smoking article of  claim 1 , wherein piercing the filter unit with a needle does not substantially affect filtering activity of the filter.  
     
     
         19 . The smoking article of  claim 1 , wherein the filter unit consists essentially of said mass of porous silica or resin particles.  
     
     
         20 . A filter cartridge for removal of components from cigarette smoke, comprising a hollow sleeve packed with porous silica or resin particles, wherein said porous silica or resin particles have an average particle size of from about 35 to about 400 μm.  
     
     
         21 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have chemically bonded to their surfaces functional groups that exhibit preferential affinity for said components and that reversibly bind said components to elute components having a lower affinity than a previously bound component.  
     
     
         22  The filter cartridge of  claim 21 , wherein the functional groups are bonded to the porous silica or resin particles by one of (i) direct bonding to surface atoms of the silica or resin particles, (ii) ester bonded to surface hydroxyl groups of the silica or resin particles, and (iii) bonded to the silica or resin particles by treatment of the silica or resin particles with an organosilane.  
     
     
         23 . The filter cartridge of  claim 21 , wherein the functional groups have the general formula:  
       R 1 (CH 2 ) n — wherein: 
 n is an integer from 1 to 40; and  
 R 1  is hydrogen, hydroxy, amine, amide, cyano, nitrile, nitro, thio, sulfide, sulfone, sulfoxide, I, Br, Cl, F, or an alkyl or aryl group of from 1 to 40 carbon atoms which may be straight or branched, saturated or unsaturated and is optionally substituted with one or more atoms selected from the group consisting of O, N, S, I, Br, Cl and F.  
   
     
     
         24 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average particle size of from about 40 to about 200 μm.  
     
     
         25 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average particle size of from about 35 to about 80 μm.  
     
     
         26 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average porosity of from about 10 Å to about 1000 Å.  
     
     
         27 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average porosity of from about 50 Å to about 1000 Å.  
     
     
         28 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average porosity of from about 60 Å to about 1000 Å.  
     
     
         29 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles have an average porosity of from about 150 Å to about 500 Å.  
     
     
         30 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles are selected from the group consisting of polymeric materials, silica based materials, composites of polymeric materials and silica based materials, and mixtures thereof.  
     
     
         31 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles are selected from the group consisting of methacrylate, methyl methacrylate, ethylmethacrylate, styrene, styrene divinylbenzene, silica, magnesium silicate, ceramic, porous glass, and composite resins of silica and polymeric materials.  
     
     
         32 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles are porous silica beads.  
     
     
         33 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles form a packed column having a hollow space of at least 45%.  
     
     
         34 . The filter cartridge of  claim 20 , wherein the filter cartridge has an efficiency of about 50% or more.  
     
     
         35 . The filter cartridge of  claim 20 , wherein the porous silica or resin particles form a packed column having a hollow space of at least 67%.  
     
     
         36 . The filter cartridge of  claim 20 , wherein piercing the filter unit with a needle does not substantially affect filtering activity of the filter.  
     
     
         37 . The filter cartridge of  claim 20 , wherein the filter cartridge consists essentially of said hollow sleeve packed with said porous silica or resin particles.