On line formation of recessed cigarette filter

Abstract

A process for the on line production of cigarette filters comprises the steps of conveying a continuous thin flexible substrate past a source of smoke altering particulate material, such as adsorbents, catalysts and flavorants. An electrostatic charge is applied onto the substrate upstream of the source of particulate material. A layer of particulate material from the source is deposited onto the substrate with the thickness of the layer depending upon the strength of the electrostatic charge. The coated substrate is then cut into pieces, and the pieces are placed into the cavities between spaced apart filter components. In an alternative process, filter paper is coated with smoke altering particulate material by electrostatic deposition techniques, and spaced apart filter components are placed onto the particulate coated filter paper which is then folded around the filter components.

We claim:  
     
         1 . A process for producing cigarette filters comprising the steps of: 
 a) conveying a continuous thin flexible substrate past a source of smoke altering particulate material;    b) applying an electrostatic charge onto the substrate upstream of the source of particulate material;    c) depositing a layer of particulate material from the source onto the substrate with the thickness of layer depending upon the strength of the electrostatic charge on the substrate;    d) cutting the particulate coated substrate into pieces; and    e) placing those pieces into cavities between spaced apart filter components.    
     
     
         2 . A process as in  claim 1  wherein the substrate is paper.  
     
     
         3 . A process as in  claim 1  wherein the substrate is a nonwoven material.  
     
     
         4 . A process as in  claim 1  wherein the particulate material is selected from the group consisting of adsorbents, catalysts and flavorants.  
     
     
         5 . A process as in  claim 1  wherein the particulate material is an adsorbent selected from the group consisting of carbon, zeolite and APS silica gel.  
     
     
         6 . A process as in  claim 1  wherein the step of applying the electrostatic charge is variable whereby the thickness of the layer of particulate material is variable depending upon the strength of the electrostatic charge on the substrate.  
     
     
         7 . A process as in  claim 1  including the further step of: 
 f) rolling each of the cut pieces into a cylindrical plug form before placement thereof into the cavities between spaced apart filter components.  
 
     
     
         8 . A process as in  claim 1  including the step of adding flavor to the particulate material.  
     
     
         9 . A process as in  claim 1  including the step of: 
 a) depositing multiple layers of particulate material onto the substrate.  
 
     
     
         10 . A process as in  claim 9  wherein the multiple layers of particulate material are on opposite sides of the substrate.  
     
     
         11 . A process for producing cigarette filters comprising the steps of: 
 a) conveying a continuous thin flexible substrate past a source of smoke altering particulate material;    b) applying an electrostatic charge onto the substrate upstream of the source of particulate material;    c) depositing a layer of particulate material from the source onto the substrate with the thickness of layer depending upon the strength of the electrostatic charge on the substrate;    d) placing spaced apart filter components on the particulate coated substrate; and    e) folding the particulate coated substrate around the filter components.    
     
     
         12 . A process as in  claim 11  wherein the step of applying the electrostatic charge is variable whereby the thickness of the layer of particulate material is variable depending upon the strength of the electrostatic charge on the substrate.  
     
     
         13 . A process as in  claim 11  wherein the continuous substrate is filter paper.  
     
     
         14 . A process as in  claim 11  wherein the spaced apart filter components placed on the particulate coated substrate comprise cellulose acetate plugs.  
     
     
         15 . A process as in  claim 11  wherein the particulate material is selected from the group consisting of adsorbents, catalysts and flavorants.  
     
     
         16 . A process as in  claim 11  wherein the particulate material is an adsorbent selected from the group consisting of carbon, zeolite and APS silica gel.  
     
     
         17 . A filter plug for a cigarette filter comprising a flexible substrate piece with at least one layer of electrostatically deposited smoke altering particulate material on the substrate.  
     
     
         18 . A filter plug as in  claim 17  wherein the substrate is paper.  
     
     
         19 . A filter plug as in  claim 17  wherein the substrate is a nonwoven material.  
     
     
         20 . A filter plug as in  claim 17  wherein the particulate material is selected from the group consisting of adsorbents, catalysts and flavorants.  
     
     
         21 . A filter plug as in  claim 17  wherein the particulate material is an adsorbent selected from the group consisting of carbon, zeolite and APS silica gel.  
     
     
         22 . A filter plug as in  claim 17  wherein the flexible substrate piece with at least one layer of electrostatically deposited smoke altering particulate material on the substrate is in the form of a roll having a cylindrical shape.  
     
     
         23 . A filter plug as in  claim 17  wherein the flexible substrate piece has plural layers of electrostatically deposited particulate material on the substrate.  
     
     
         24 . A filter plug as in  claim 23  wherein the plural layers are both on one side of the substrate.  
     
     
         25 . A filter plug as in  claim 23  wherein the plural layers are on opposite sides of the substrate.  
     
     
         26 . A filter plug as in  claim 17  wherein the at least one layer of electrostatically deposited particulate material forms a pattern on the substrate.