US Patent 8464728 Biodegradable composites

The present invention concerns a biodegradable cigarette filter tow comprising composite filaments of cellulose and cellulose acetate, and a process for making such a filter tow comprising providing a solution dope comprising a blend of cellulose and cellulose acetate in an ionic liquid or in N-methylmorphilone-N-oxide (NMMO), and spinning casting the blend into a protic solvent to generate fibers or films, and converting the fibers or films into cigarette filter tow. The invention also concerns cigarette filters and cigarettes made from such a filter tow.