Filter for smoking article

Abstract

The present invention addresses the problem of providing a filter for a smoking article that can reduce a stimulus component such as formaldehyde, and that does not reduce any more than necessary a component affecting the smoke flavor included in mainstream smoke. This problem is solved by providing a smoking article filter comprising a filter segment that has a porous material containing: a hydrotalcite particle; and a nonfibrous binder resin.

What is claimed is: 
     
         1 . A filter for a smoking article, the filter comprising
 a filter segment including
 a porous material containing 
 a hydrotalcite particle and 
 a nonfibrous binder resin. 
   
     
     
         2 . The filter for a smoking article according to  claim 1 , wherein
 the porous material further contains a cellulose particle.   
     
     
         3 . The filter for a smoking article according to  claim 2 , wherein
 the hydrotalcite particle and the cellulose particle are in a weight ratio of from 10:90 to 30:70.   
     
     
         4 . The filter for a smoking article according to  claim 1 , wherein
 the hydrotalcite particle is formed of a hydrotalcite compound represented by the formula (1):
   M 2+   1-x M 3+   x (OH) 2 (A n− ) x/n .mH 2 O  (1)
 
   
       wherein M 2+  is a divalent metal ion selected from the group consisting of Mg, Zn, Ni, and Ca, M 3+  is Al ion, A n−  is an anion having a valency of n and selected from the group consisting of CO 3 , SO 4 , OOC—COO, Cl, Br, F, NO 3 , Fe(CN) 6   3− , Fe(CN) 6   4− , phthalic acid, isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and derivatives thereof, malic acid, salicylic acid, acrylic acid, adipic acid, succinic acid, citric acid and sulfonic acid, 0.1<x<0.4, and 0<m<2. 
     
     
         5 . The filter for a smoking article according to  claim 1 , wherein
 the hydrotalcite particle has a mean particle diameter of from 200 to 800 μm.   
     
     
         6 . The filter for a smoking article according to  claim 1 , wherein
 the nonfibrous binder resin is a thermoplastic resin.   
     
     
         7 . The filter for a smoking article according to  claim 1 , wherein
 the filter segment including the porous material containing the hydrotalcite particle and the nonfibrous binder resin includes no plasticizer.   
     
     
         8 . The filter for a smoking article according to  claim 1 , wherein
 the hydrotalcite particle and the nonfibrous binder resin are at a weight ratio of from 70:30 to 80:20 in the porous material.