This application claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 60/924,814, filed on May 31, 2007, the entire content of which is incorporated herein by reference.
Cigarettes typically comprise filters that may have adsorbent materials, such as carbon, incorporated therein. Filters adapted to be incorporated in a filter cigarette may comprise, for example, particles or granules of carbon such as activated carbon or activated charcoal and/or other adsorbent materials incorporated within the cellulose acetate tow or in cavities between cellulose acetate material.
During smoking of a cigarette, to the extent that adsorbent particles or fragments of adsorbent particles could possibly be entrained in mainstream smoke and issue through (i.e., breakthrough) the mouth end of the cigarette, techniques to reduce the amount of adsorbent particle breakthrough in mainstream smoke would be of interest.
Provided is a filter assembly for a smoking article having reduced adsorbent particle breakthrough.
In a preferred embodiment, the filter assembly is a plug-space-plug filter. Preferably, the filter assembly includes a plug of electrostatically charged fiber material and an adsorbent. Most preferably, a plug of electrostatically charged fiber material is located downstream of the adsorbent. In a preferred embodiment, the plug of electrostatically charged fiber material includes randomly-oriented electrostatically charged fiber material. In another embodiment, the plug of electrostatically charged fiber material includes axially oriented electrostatically charged fiber media. In an embodiment, at least one plug of axially oriented cellulose acetate fibers is located upstream and/or downstream of the adsorbent. In yet another embodiment, at least one plug of axially oriented cellulose acetate fibers is located downstream of the plug of electrostatically charged fiber material.
Also provided is a smoking article. In a preferred embodiment, the smoking article includes a tobacco rod and a filter assembly.
Also provided is a method of making a filter assembly for smoking articles that provides reduced and/or eliminated carbon particle breakthrough in mainstream smoke.
FIG. 1 illustrates a prior art plug-space-plug filter for a smoking article.
FIG. 2 illustrates an embodiment of a plug-space-plug filter including a plug of electrostatically charged fiber material.
FIG. 3 illustrates a second embodiment of a plug-space-plug filter including a plug of electrostatically charged fiber material.
FIG. 4 illustrates a third embodiment of a plug-space-plug filter including a plug of electrostatically charged fiber material.
FIG. 5 illustrates a partially unwrapped smoking article including a plug-space-plug filter including a plug of electrostatically charged fiber material.
