High surface area micro-porous fibers from polymer solutions
AssigneePhilip Morris Incorporated
InventorsLixin Xue, Kent B. Koller, Qiong Gao
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Abstract
Fibers are produced from an acetone solution of cellulose acetate by pulling or extruding such material through a spinneret in a dry spinning process. A vacuum is applied to the thus formed fibers after a certain degree of drying. A dried outer skin is formed, and the vacuum causes the solvent inside the skin to explode or pop and exit the fiber along micro-porous paths thereby producing high surface area fibers with micro-porous cavities and internal void volume. Such micro-cavities are particularly useful for retaining solid and/or liquid reagents in a cigarette filter for selective filtration of various smoke components.
Claims3
A cellulose acetate fiber having an outside surface area with a plurality of micro-porous cavities that extend from the surface into the fibers, and the fibers having a partial internal void volume.
A cigarette filter element comprising a plurality of cellulose acetate fibers each having an outside surface area with a plurality of micro-porous cavities that extend from the surface into the fibers, and solid and/or liquid reagent retained within the micro-cavities for selective filtration of tobacco smoke.
A process of preparing cellulose acetate fibers comprising the steps of passing an acetone solution of cellulose acetate through a spinneret to form fibers, partially drying the formed fibers to produce a skin on the outside of the fibers, and applying a vacuum to the formed fibers after a predetermined degree of drying to thereby cause the acetone inside the formed fibers to explode or pop and exit the fibers through the skin along micro-porous paths whereby micro-porous cavities are formed on the outside surface of the fibers extending to inside the fibers.
Dependencies are inferred from the claim text.