Biodegradable cigarette filter

Abstract

A biodegradable bi-component fiber may include a polyhydroxyalkanoate and/or polylactic acid with cellulose acetate and/or plasticized cellulose acetate for use in a filter material configured for use in a filter of a smoking article. The bi-component fiber may have a sheath-core construction where one component of the bi-component forms the core, and the other component forms the sheath of each fiber. A filter made in accordance with this design may also include non-biodegradable material.

1 . A filter material configured for use as part of a smoking article, comprising:
 a plurality of bi-component fibers assembled as fibrous filter tow, each fiber including a core comprising a first degradable polymer material including polylactic acid or a polyhydroxyalkanoate and a sheath comprising a second polymer material including at least a cellulose ester and a plasticizer;   wherein the core comprises a higher melt temperature than the sheath; and   wherein at least one of the first degradable polymer material and the second polymer material further comprises particles of starch and/or particles of cellulose.   
     
     
         2 . The filter material of  claim 1 , wherein the second material comprises polylactic acid. 
     
     
         3 . The filter material of  claim 1 , wherein the sheath further comprises cellulose acetate. 
     
     
         4 . The filter material of  claim 1 , wherein the particles comprise 5 percent to 30 percent by weight of an overall dry weight of the filter material. 
     
     
         5 . The filter material of  claim 1 , wherein the core comprises at least about 60 percent to about 95 percent by volume of the bi-component fibers. 
     
     
         6 . The filter material of  claim 1 , wherein the core comprises at least 80 percent by volume of the bi-component fibers. 
     
     
         7 . The filter material of  claim 1 , wherein the particles are soluble in water to at least 50 g/L. 
     
     
         8 . The filter material of  claim 1 , further comprising a state of being formed into a filter element and being attached to tobacco material so as to form a smoking article. 
     
     
         9 . The filter material of  claim 1 , where the core first degradable material consists of polylactic acid. 
     
     
         10 . The filter material of  claim 9 , where the sheath comprises plasticized cellulose acetate. 
     
     
         11 . A method of making filter material of  claim 10 , comprising a step of coextruding the plasticized cellulose acetate with the polylactic acid core. 
     
     
         12 . A method of making filter material of  claim 10 , comprising applying cellulose acetate solution together with a plasticizer onto core polylactic acid fiber. 
     
     
         13 . A method of making filter material of  claim 10 , comprising applying cellulose acetate solution as a sheath onto core polylactic acid fiber and thereafter applying a plasticizer to the cellulose acetate sheath. 
     
     
         14 . A filter material configured for use as part of a smoking article, comprising:
 a plurality of bi-component fibers assembled as fibrous filter tow, each fiber including a core comprising a first degradable polymer material including polylactic acid or a polyhydroxyalkanoate and a sheath comprising a second polymer material including at least a cellulose ester and a plasticizer;   wherein the core comprises a higher melt temperature than the sheath;   wherein at least one of the first degradable polymer material and the second polymer material further comprises particles of starch and/or particles of cellulose; and   where the second material further comprises a degradable material selected from the group consisting of polyhydroxypropionate, polyhydroxyvalaerate, polyhydroxybutyrate, polyhydroxyoctanoate, polylactic acid, polycaprolactone, polybutylene succinate adipate, polyvinyl alcohol, starch, polyesteramide, and regenerated cellulose.   
     
     
         15 . The filter material of  claim 14 , wherein the core comprises at least about 60 percent to about 95 percent by volume of the bi-component fibers. 
     
     
         16 . The filter material of  claim 14 , wherein the second polymer material selected is polylactic acid. 
     
     
         17 . The filter material of  claim 14 , wherein the second polymer material is cellulose acetate. 
     
     
         18 . The filter material of  claim 17 , wherein the cellulose acetate is plasticized. 
     
     
         19 . The filter material of  claim 14 , wherein the particles are soluble in water to at least 50 g/L. 
     
     
         20 . The filter material of  claim 14 , wherein the particles comprise 5 percent to 30 percent by weight of an overall dry weight of the filter material.