Filter for the sorption of components of tobacco smoke which are harmful to health

Abstract

A filter for sorption of components of tobacco smoke which are harmful to health comprises ceramic particles bonded to form a porous structure (12). In order to avoid contamination within a short period of time even when the filter is not properly disposed of, and without causing a loss in sorption or in the smoking sensation, the filter has decreasing water solubility from a tobacco-side portion (1) to an opposite mouth-side portion (2).

1 . A filter for sorption of components of tobacco smoke that are harmful to health, said filter comprising:
 ceramic particles bonded to form a porous structure;   wherein the filter has decreasing water solubility from a tobacco-side portion to an opposite mouth-side portion.   
     
     
         2 . The filter according to  claim 1 , wherein the ceramic particles are bonded with a water-soluble binder, the water-soluble binder having a mass fraction that increases from the tobacco-side portion to the opposite mouth-side portion of the filter. 
     
     
         3 . The filter according to  claim 2 , wherein the filter further comprises a third portion, said tobacco-side portion, said mouth-side portion, and the third portion each having a respective different and constant binder content. 
     
     
         4 . The filter according to  claim 3 , wherein the third portion comprises at least one middle portion, and the binder content in the tobacco-side portion is in a range of 1-2 wt %, in the at least one middle portion in a range of 2-3 wt %, and in the mouth-side portion in a range of 3-4 wt %. 
     
     
         5 . The filter according to  claim 1 , wherein the filter has a porosity that increases from the tobacco-side portion to the opposite mouth-side portion. 
     
     
         6 . The filter according to  claim 5 , wherein the filter further has a third portion, said tobacco-side portion, said mouth-side portion, and the third portion each having a respective porosity that differs from the porosities of the other portions and is constant in said portion. 
     
     
         7 . The filter according to  claim 6 , wherein the third portion comprises at least one middle portion, and the porosity in the tobacco-side portion is in a range of 35-50%, in the middle portion in a range of 50-65% and in the mouth-side portion (23 in a range of 65-80%. 
     
     
         8 . The filter according to  claim 1 , wherein the filter has an elasticity that decreases inwardly in a radial direction of the filter. 
     
     
         9 . The filter according to  claim 1 , wherein the filter has a porosity that increases radially outwardly from a filter core to a filter shell of the filter. 
     
     
         10 . The filter according to  claim 9 , wherein at least one intermediate portion ( 18 ) is supported between a filter core portion having a predetermined placeholder particle fraction and a filter shell portion surrounding the filter core and having a placeholder particle fraction higher than the predetermined placeholder particle fraction, wherein the placeholder particle fraction of said intermediate portion lies between the placeholder particle fractions of the filter core portion and the filter shell portion. 
     
     
         11 . A method for producing a filter for sorption of tobacco smoke, said method comprising:
 filling successively mutually different mixtures comprising ceramic particles, placeholder particles and water-soluble binder into a mold; and   pressing and heating contents of the mold so as to decompose the place-holder particles and to bond the ceramic particles so as to form a porous structure.   
     
     
         12 . A device for producing a filter according to  claim 1 , comprising
 a continuous casting mold that has inlet channels; and   a heating unit and a separating device supported downstream of said inlet channels in a casting direction, a heating unit and a separating device;   wherein the continuous casting mold has characterized in that at least two inlet channels that extend at a distance into one another and are arranged coaxially with respect to one another and with respect to the continuous casting mold.   
     
     
         13 . The device according to  claim 12 , wherein wherein some of the inlet channels have a larger diameter and some of the inlet channels have a smaller diameter, wherein the inlet channels with the larger diameter project beyond the inlet channels with the smaller diameter in the casting direction. 
     
     
         14 . The device according to  claim 13 , wherein the continuous casting mold is one of a plurality of continuous casting molds extending parallel to one another that are formed into a continuous casting module, and said continuous casting module is one of a plurality of continuous casting modules that are arranged on a common base body, wherein the base body supports the heating unit and the separating unit comprises a rotor blade extending between the heating unit and the continuous casting molds. 
     
     
         15 . A method for the continuous production of a filter for the sorption of tobacco smoke, said method comprising:
 initially introducing mixtures differing from one another and comprising ceramic particles, placeholder particles and water-soluble binder into a continuous casting mold through at least two inlet channels that extend into one another at a distance and are arranged coaxially with one another and with respect to the continuous casting mold;   varying inlet velocities of the mixtures differing from one another in the respective inlet channels in a radial and/or axial direction of the filter so as to adjust water solubility and/or the porosity of the filter, and then   fractionating and heating the continuous casting mold contents are so as to decompose the placeholder particles and bind the ceramic particles so as to form the porous structure of said bound ceramic particles.   
     
     
         16 . The filter according to  claim 4 , wherein the filter has a porosity that increases from the tobacco-side portion to the opposite mouth-side portion, and said tobacco-side portion, said mouth-side portion, and the third portion each have a respective porosity that differs from the porosities of the other portions, wherein the porosity in the tobacco-side portion is in a range of 35-50%, in the middle portion in a range of 50-65% and in the mouth-side portion in a range of 65-80%. 
     
     
         17 . The filter according to  claim 16 , wherein the filter has
 an elasticity that decreases inwardly in a radial direction of the filter, and   a porosity that increases radially outwardly from a filter core to a filter shell of the filter.   
     
     
         18 . The filter according to  claim 17 , wherein at least one intermediate portion is supported between a filter core portion having a predetermined placeholder particle fraction and a filter shell portion surrounding the filter core and having a placeholder particle fraction higher than the predetermined placeholder particle fraction, wherein the placeholder particle fraction of said intermediate portion lies between the placeholder particle fractions of the filter core portion and the filter shell portion.