Cellulose esters having mixed-phase titanium dioxide particles for improved degradation

Abstract

Degradable cellulose esters are disclosed that have incorporated therein or thereon mixed-phase titanium dioxide particles. The esters may be in the form of filters prepared by applying a plasticizer, having the mixed-phase titanium dioxide particles dispersed therein, to cellulose ester fibers to obtain plasticized cellulose ester fibers; and thereafter forming the plasticized cellulose ester fibers into a filter. Alternatively, the particles may be added to the dope from which the fibers are spun, or blended with a cellulose ester intended for molded articles.

1 . An article comprising a cellulose ester having incorporated therein or thereon mixed-phase titanium dioxide particles. 
     
     
         2 . The article of  claim 1 , wherein the cellulose ester is in the form of cellulose ester fibers. 
     
     
         3 . The article of  claim 2 , wherein the article is in the form of a filter prepared by a process comprising applying a plasticizer, having the mixed-phase titanium dioxide particles dispersed therein, to the cellulose ester fibers to obtain plasticized cellulose ester fibers; and
 thereafter forming the plasticized cellulose ester fibers into a filter.   
     
     
         4 . The article of  claim 3 , wherein the plasticizer comprises one or more of: triacetin (glycerol triacetate), diethylene glycol diacetate, triethylene glycol diacetate, methyl phthalyl ethyl glycollate, dibutyl phthalate, tripropionin, acetyl triethyl citrate, triethyl citrate, and mixtures of triacetin and one or more polyethylene glycols. 
     
     
         5 . The article of  claim 3 , wherein the mixed-phase titanium dioxide particles comprise an anatase phase present in an amount from 50% to 98%, and a rutile phase present in an amount from 2% to 50%, in each case as measured by x-ray crystallography. 
     
     
         6 . The article of  claim 1 , wherein the article is in the form of a yarn. 
     
     
         7 . The article of  claim 1 , wherein the article is in the form of a fabric. 
     
     
         8 . The article of  claim 1 , wherein the mixed-phase titanium dioxide particles have a surface area from about 10 to about 300 sq. m/g. 
     
     
         9 . The article of  claim 1 , wherein the mixed-phase titanium dioxide particles have an average particle size from about 1 nm to about 100 nm. 
     
     
         10 . The article of  claim 1 , wherein the mixed-phase titanium dioxide particles have an average particle size from 5 nm to 50 nm. 
     
     
         11 . The article of  claim 1 , wherein the mixed-phase titanium dioxide particles are carbon-modified titanium dioxide particles. 
     
     
         12 . The article of  claim 2 , wherein the mixed-phase titanium dioxide particles are dispersed in the cellulose ester fibers. 
     
     
         13 . The article of  claim 12 , wherein the mixed-phase titanium dioxide particles are dispersed in the cellulose ester fibers by being dispersed in the solvent from which the fibers are spun. 
     
     
         14 . The article of  claim 1 , wherein the cellulose ester comprises one or more of a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, or a cellulose acetate butyrate. 
     
     
         15 . The article of  claim 1 , wherein the cellulose ester fiber comprises a cellulose acetate having a DS/AGU from about 1.8 to about 2.7. 
     
     
         16 . The article of  claim 1 , wherein the cellulose ester comprises a cellulose acetate having a DS/AGU from about 1.9 to about 2.5. 
     
     
         17 . The article of  claim 1 , wherein the amount of mixed-phase titanium dioxide particles provided to the article is from about 0.01 to about 20 wt. %, based on the weight of the article. 
     
     
         18 . The article of  claim 3 , wherein the filter further comprises one or more slits. 
     
     
         19 . A cigarette comprising the article of  claim 2 . 
     
     
         20 . The article of  claim 1 , wherein the article is in the form of a molded article.