Magnetic filter elements and cigarettes having magnetic filter elements

Abstract

A magnetic cigarette filter element is provided comprising a filter material and at least one magnetic substrate. The magnetic substrate can comprise at least one monolithic ferromagnetic substrate in the shape of a disc, ring, ribbon, mesh, rod, cylinder and/or spheroid that is incorporated in, on and/or around the filter rod. The magnetic substrate can filter (i.e., magnetically attract and trap) ferromagnetic particles from the mainstream smoke of a cigarette comprising the magnetic cigarette filter.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under 35 U.S.C. .sctn.119(e) to U.S. provisional Application No. 60/787,524, filed on Mar. 31, 2006, the entire content of which is incorporated herein by reference.

BACKGROUND

[0002] In the description that follows reference is made to certain structures and methods, however, such references should not necessarily be construed as an admission that these structures and methods qualify as prior art under the applicable statutory provisions. Applicants reserve the right to demonstrate that any of the referenced subject matter does not constitute prior art.

[0003] U.S. Pat. Nos. 5,191,905; 4,260,523 and 4,258,730 disclose an active carbon composition that comprises a magnetized material for the catalytic removal from cigarette smoke of carbon monoxide, hydrogen and the like. U.S. Pat. Nos. 6,615,843 and 5,468,529 discloses a tobacco smoke filter composition comprising a magnetic filter material.

[0004] The incorporation of nanoscale particle additives (e.g., nanoscale catalysts) into one or more components of a cigarette is disclosed in commonly-owned U.S. patent application Ser. Nos. 10/460,632; 10/460,631; 10/460,303; 10/460,210 and U.S. Patent Publication No. 2003/0075193, the disclosures of which are hereby incorporated reference. To the extent that, during the smoking of a cigarette, loose nanoscale particle additives could possibly be entrained in mainstream smoke, techniques to reduce the amount of nanoscale particle additives in mainstream smoke would be of interest.

SUMMARY

[0005] Provided is a filter element adapted to be formed into a cigarette and a cigarette comprising the filter element wherein the filter element comprises a filter material and at least one magnetic substrate. The at least one magnetic substrate can filter (via magnetic attraction) ferromagnetic particles from mainstream smoke. Optionally, the at least one magnetic substrate can change the chemical composition of mainstream smoke that flows through the filter element.

[0006] Also provided is a method of making a cigarette filter element comprising at least one magnetic substrate, comprising (i) providing a filter material and plug wrap material; (ii) incorporating at least one magnetic substrate in and/or on at least one of the filter material and plug wrap material; and (iii) wrapping the filter material in the plug wrap material to form the filter element.

[0007] The magnetic substrate can comprise an electromagnet or a permanent magnet. In one embodiment the magnetic substrate, which is capable of filtering ferromagnetic particles (e.g., nanoscale iron oxide particles) from the mainstream smoke of the cigarette, consists essentially of a magnetic material selected from the group consisting of ferrite magnets, neodymium iron boron magnets, samarium cobalt magnets, aluminum nickel cobalt magnets and mixtures thereof. The at least one magnetic substrate can have at least one dimension (e.g., length, width and/or thickness) greater than about 1 mm or greater than about 2 mm. Preferably, the magnetic substrate can reduce the amount of ferromagnetic particles entrained in the mainstream smoke of the cigarette by at least 10%. The magnetic substrate preferably has a Curie temperature of at least about 300.degree. C.

[0008] The filter material is selected from the group consisting of cellulose ester fibers, regenerated cellulose, polyamide fibers, polyimide fibers, acrylic fibers, polyester fibers, polycarbonate fibers, polyethylene fibers, polyvinyl chloride fibers, filamentary polyolefin materials, polypropylene fibers, wood pulp fibers, cotton, flax, jute, wool, silk, ramie, protein fibers, paper and mixtures thereof. The cigarette filter element can comprise a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, a free-flow filter or combinations thereof.

[0009] The at least one magnetic substrate, which can be incorporated in, on and/or around the filter material, can be incorporated into one or more cigarette filter parts selected from the group consisting of a shaped paper insert, a plug, a space between plugs, cigarette filter paper, a cellulose acetate sleeve, a polypropylene sleeve and a free-flow sleeve. Magnetic beads, for example, can be incorporated into filter material and/or cigarette filter paper by dusting or spraying. A magnetic substrate can be formed at least partially around the filter material (e.g., a magnetic ring can be formed around the filter material) prior to wrapping the filter material in cigarette paper (e.g., plug wrap).

[0010] According to an embodiment, the filter material can be wrapped in cigarette paper (e.g., plug wrap) wherein the magnetic substrate is disposed on an inner surface of the cigarette paper. For example, the magnetic substrate can be adhered to an inner surface of the cigarette paper with an adhesive. The magnetic substrate can be incorporated in the filter rod (e.g., incorporated in the filter material) and/or incorporated between the filter rod and the tobacco rod of a cigarette. The distribution of the magnetic substrate throughout the filter element can be homogeneous but is preferably non-homogeneous.

[0011] The at least one magnetic substrate can comprise a disc, ring, ribbon, mesh, rod, cylinder or spheroid that can be in incorporated in, on and/or around the filter material. Preferably the magnetic substrate comprises a non-porous magnetic material that is at least 50% of its theoretical density. The magnetic material is preferably sintered material.

[0012] The cigarette filter element can further comprise an adsorbent, flavorant or catalyst and the tobacco rod can further comprise nanoscale particles. The resistance to draw through a cigarette filter element comprising a magnetic substrate is preferably less than about 5 inches of water at an air flow velocity of about 1050 cc/min.

[0013] Also provided is a method of smoking a cigarette having a filter element comprising a magnetic substrate comprising heating or lighting the cigarette to form smoke and drawing the smoke through the cigarette wherein the magnetic substrate filters ferromagnetic particles from the mainstream smoke.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a perspective view of a cigarette according to an embodiment wherein magnetic beads are incorporated throughout the filter material of a filter element.

[0015] FIG. 2 is a perspective view of a cigarette according to an embodiment wherein magnetic beads are incorporated within a filter element as a gas permeable bed.

[0016] FIG. 3 is a perspective view of a cigarette according to an embodiment wherein a magnetic ring is around the filter rod of a filter element.

[0017] FIG. 4 is a perspective view of a cigarette according to an embodiment wherein magnetic rods are incorporated axially along a surface of the filter rod of a filter element.

[0018] FIG. 5 is a perspective view of a cigarette according to an embodiment wherein a magnetic rod is incorporated axially within the filter rod of a filter element.

[0019] FIG. 6 is a perspective view of a cigarette according to an embodiment wherein a magnetic mesh is incorporated along an outer surface of the filter rod of the filter element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0020] A filter element for a cigarette comprises a cigarette filter material and at least one magnetic substrate that is incorporated in, on and/or around the filter material to form the filter element. The cigarette filter element, which is preferably wrapped in cigarette paper (e.g., plug wrap), comprises a filter rod of filter material and the magnetic substrate. The filter element can be attached to a tobacco rod (e.g., attached with tipping paper) to form a filter cigarette. The at least one magnetic substrate is adapted to filter (i.e., magnetically attract) ferromagnetic particles such as iron oxide entrained in mainstream cigarette smoke. A method for producing the filter element is also provided.

[0021] The term "mainstream" smoke refers to the mixture of gases passing down the tobacco rod and issuing through the filter end, i.e., the amount of smoke issuing or drawn from the mouth end of a cigarette during smoking of the cigarette. The mainstream smoke contains smoke that is drawn in through both the lighted region, as well as through the cigarette paper wrapper. Nanoscale particles incorporated that are incorporated into the tobacco rod and/or cigarette paper of a cigarette (e.g., nanoscale particles of iron oxide) may be entrained in mainstream smoke during smoking.

[0022] The term "magnetic substrate" as used herein refers to a monolithic magnetic material having at least one dimension of at least 1 mm. For example, a magnetic substrate can comprise one or more magnetic beads. Preferred magnetic beads can have an average particle size of greater than 1 mm (e.g., at least 2, 3, 4 or 5 mm). The shape of the magnetic beads can be substantially spherical or non-spherical. A magnetic substrate can have any shape suitable for incorporation in a filter element. A magnetic substrate can be, for example, a disc, ring, ribbon, mesh, rod or cylinder. As is recognized by one with ordinary skill in the art, the size and shape of the at least one magnetic substrate can be selected so as to incorporate the at least one magnetic substrate into the filter element. A filter element can comprise one or more magnetic substrates.

[0023] In embodiments where the magnetic substrate is a rod or cylinder, preferably the length of the rod or cylinder is greater than 4 times the diameter.

[0024] As mentioned above, the magnetic substrates preferably comprise at least one dimension greater than 1 mm. Generally, the field strength of a magnet made from a particular magnetic material is proportional to the magnet's size (e.g., volume). Preferred magnetic substrates are sized and shaped to be effective filters for ferromagnetic particles when the magnetic substrates are incorporated in the filter element of a cigarette.

[0025] Magnetic materials are well known and the cigarette filter element can comprise at least one magnetic substrate made from any magnetic material capable of filtering ferromagnetic particles. The magnetic substrate can comprise an electromagnet or a permanent magnet. In an exemplary embodiment, the magnetic material used to form the magnetic substrate is selected from the group consisting of ferrite magnets (e.g., magnetic compositions comprising iron oxide and strontium oxide or barium oxide), neodymium iron boron (NdFeB) magnets, samarium cobalt magnets (e.g., SmCo.sub.5, Sm.sub.2Co.sub.17, etc.), aluminum nickel cobalt magnets (e.g., alloys of aluminum, nickel, cobalt and iron) and mixtures thereof.

[0026] Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization. Ferromagnetism manifests itself in the fact that an externally imposed magnetic field can cause the magnetic domains to line up with each other which, in turn, magnetizes the material.

[0027] The thermal response of magnetic materials is well understood. As is known to those having ordinary skill in the art, the spontaneous magnetization within a magnetic material decreases with increasing temperature. The temperature above which spontaneous magnetization cannot occur in a magnetic substrate is known as the Curie temperature. Accordingly, the range of effective filtration temperatures of the magnetic substrate is below its Curie temperature. The Curie temperature of neodymium iron boron magnets is typically in the range of about 300 to 350.degree. C. Samarium cobalt magnets and aluminum nickel cobalt magnets typically have a Curie temperature in the range of about 750 to 800.degree. C., and about 800 to 900.degree. C., respectively. Preferably the magnetic substrates that are incorporated in the filter element have a Curie temperature sufficiently high to retain their magnetic properties during the smoking of a cigarette. In a preferred embodiment, the at least one magnetic substrate has a Curie temperature of greater than about 300.degree. C.

[0028] The magnetic substrate can be fully or partially dense. The magnetic substrate can comprise a monolith having 100% or less of its theoretical density (e.g., a substrate that is about 50, 60, 70, 80 or 90% dense). The magnetic substrate can be in the shape of a fully dense ring or disc of magnetic material, or the magnetic substrate can be in the shape of a porous ring or disc (e.g., frit). In a further embodiment, the magnetic substrate can comprise an electromagnet. Ferromagnetic particles can be filtered from mainstream smoke via magnetic attraction to the at least one magnetic substrate that is incorporated in the filter element. The filter material (e.g., cellulose acetate) that comprises the bulk of the filter element is preferably not magnetic.

[0029] Cigarette filters are made in a variety of designs. Typically, cigarette filters comprise four main components: a filter tow such as a bundle of cellulose acetate fibers or paper that comprise the bulk of the filter; a plasticizer (i.e., a softening agent added to bind the filter fibers together into a filter rod); a plug wrap (i.e., a paper wrapper that is used to contain the filter material); and an adhesive used to secure the plug wrap to the filter rod.

[0030] Cigarette filter rods are commonly made from filamentary materials. A preferred filamentary material is cellulose acetate, which is a cellulose ester. Cigarette filter rods can also be made from other cellulose ester fibers (e.g., cellulose triacetate), regenerated cellulose (e.g., rayon), polyamide fibers (e.g., nylon), polyimide fibers, acrylic fibers, polyester fibers, polycarbonate fibers, polyethylene fibers, polyvinyl chloride fibers, filamentary polyolefin materials, polypropylene fibers, wood pulp fibers, cotton, flax, jute, wool, silk, ramie, protein fibers and paper. Cigarette filter rods can be formed from combinations of these materials.

[0031] Filter rods for making cigarette filters, which can be attached to tobacco rods to produce filter cigarettes, can be made by forming a bundle or tow of the filter material into a rod using a rod forming apparatus. Typically, a filter rod comprises from about ten to thirty thousand filaments of the filter material. Conventionally, a plasticizer or binder such as triacetin is added to the tow before it is passed into the rod forming apparatus. Furthermore, the tow can be spread and fluffed up, or "bloomed," usually by placing the tow under tension and passing it over air jets. The bloomed tow can be passed through a funnel or other constricting device and then through a shaped aperture to form the filter rod.

[0032] The plasticizer, which can be added to the tow during or after blooming can enhance the bonding of the filaments to each other at their cross-over points when the tow is gathered. Addition of a plasticizer can increase the firmness of the filter rod formed from the tow. The plasticizer may also have filtration properties. The attributes of the finished filter rod (e.g., filtration efficiency, firmness, dimensional stability, etc.) can be improved by curing (e.g., heating) the plasticizer.

[0033] The filter rod can be provided with an outer layer (e.g., plug wrap) to maintain its shape. The outer layer can comprise a wrapping of cigarette paper or other sheet material. As explained below, a magnetic substrate can be incorporated into the filter rod such that the magnetic substrate is substantially surrounded by the filter material, or, in an alternative embodiment, a magnetic substrate can be incorporated into a space or cavity within the filter rod. In yet a further embodiment, a magnetic substrate can be formed wholly or partially around the filter rod.

[0034] Various filter constructions including any conventional or modified filter known in the art can be used to form the filter element that comprises a magnetic substrate. Exemplary filter structures include, but are not limited to, a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, a free-flow filter or combinations thereof. Mono filters typically contain cellulose acetate tow or cellulose paper materials. Pure mono cellulose filters or paper filter provide good tar and nicotine retention, and are highly degradable. Dual filters typically comprise a cellulose acetate mouth end and a pure cellulose or cellulose acetate segment. The length and pressure drop of the segments in a dual filter can be adjusted to provide the desired filtration (i.e., adsorption and/or absorption) and resistance to draw (RTD). Triple filters can include mouth and tobacco side segments, and a middle segment comprising paper. Cavity filters typically have two segments, e.g., acetate-acetate, acetate-paper or paper-paper, separated by a cavity. Recessed filters include an open cavity at the mouth end. The filter element can be ventilated and/or comprise additional filtration media (e.g., activated carbon), flavorings, catalysts or other additives suitable for use in a filter element. According to embodiments, the magnetic substrate can be combined with filter material used to form a filter rod and/or with a pre-formed filter rod to form the filter element. The filter element can, in turn, be incorporated into a cigarette.

[0035] The magnetic substrate can be incorporated into one or more cigarette filter parts selected from the group consisting of a shaped paper insert, a plug, a space between plugs, cigarette filter paper, a cellulose acetate sleeve, a polypropylene sleeve, and a free-flow sleeve.

[0036] The filter element, which can be attached to a tobacco rod to form a filter cigarette, can be constructed so that the magnetic substrate is adapted to filter ferromagnetic particles from the mainstream smoke of a cigarette comprising the filter element. Preferably a magnetic substrate can substantially reduce the amount of ferromagnetic particles (e.g., nanoscale ferromagnetic particles) issuing from the mainstream smoke of the cigarette. A preferred filter element comprising the at least one magnetic substrate can reduce the amount of ferromagnetic particles in mainstream smoke by at least about 10% (e.g., at least 20, 30, 40, 50% or more).

[0037] The at least one magnetic substrate, in addition to removing ferromagnetic particles from mainstream smoke, can optionally affect the organoleptic properties (e.g., aroma and/or taste) of mainstream smoke. The at least one magnetic substrate can change the chemical composition of mainstream gas that flows through a filter element comprising the magnetic substrate. For example, the magnetic substrate can catalyze the conversion of at least one gas phase constituent. A catalyst is capable of affecting the rate of a chemical reaction without participating as a reactant or product of the reaction.

[0038] Aspects of incorporating the at least one magnetic substrate into filter material and/or a filter rod to form the filter element are discussed below.

[0039] A magnetic substrate can be incorporated into the filter element in a number of ways. The magnetic substrate may be incorporated into the filter material before, during and/or after its manufacture into a filter rod. For example, a magnetic substrate can be incorporated into raw filter material or into a complete filter rod.

[0040] A magnetic substrate or plurality of substrates can be incorporated directly into the filter material used to form the filter rod. The distribution of the at least one magnetic substrate in the filter element can be homogeneous or non-homogeneous. In alternate embodiments, the at least one magnetic substrate can be evenly or unevenly distributed throughout the filter rod. For example, the magnetic beads can be more heavily loaded at the tobacco rod end, mouth end, or in the intermediate region between the tobacco rod end and the mouth end of the filter rod.

[0041] In an embodiment, one or more magnetic substrates can be employed in a hollow portion of a cigarette filter element. For example, some cigarette filters have a plug/space/plug configuration in which the plugs comprise a fibrous filter material and the space is simply a void between the two filter plugs. That void can be filled partially or wholly with one or more magnetic substrates. The magnetic substrate can comprise a gas permeable monolith such as a porous disc. A packed bed of magnetic substrates can be incorporated into such a void. A bed of magnetic beads can be located in a space between plugs of a standard cellulose acetate filter rod.

[0042] A magnetic substrate or plurality of substrates can be incorporated in a filter rod after the filter rod has been formed. As a non-limiting example, a magnetic substrate can be formed around a pre-formed filter rod. A magnetic ring, for example, can be formed (e.g., crimped) around a pre-formed filter rod such that the ring has an outer diameter that is approximately equal to the diameter of the filter rod. The radial thickness and the axial width of a magnetic ring can range from about 0.05 mm to 1 mm or more. For example, a magnetic ring can have a thickness and/or a width of at least about 0.1, 0.2, 0.5, 1 or 2 mm.

[0043] By way of a further example, a magnetic substrate can be formed on an exterior surface of a pre-formed filter rod before the rod is wrapped in cigarette paper to form the filter element. Magnetic rods or strips, for example, can be arranged axially along an exterior surface of a filter rod, between the filter rod and the cigarette paper formed around the filter rod.

[0044] In yet a further example, a sheet of magnetic substrate (e.g., magnetic foil) can be formed around a filter rod that is in turn wrapped in cigarette paper to form the filter element, or the sheet can be first combined with the plug wrap to form a laminate that is wrapped around the filter rod to form the filter element. An adhesive can be used to secure the magnetic substrate to the filter rod and/or the plug wrap. Preferably, a magnetic foil-laminated plug wrap is adapted to be formed around a filter rod such that the magnetic foil is positioned on the inner surface of the plug wrap (e.g., in contact with the filter material).

[0045] The magnetic substrate(s) whether blended directly with the filter material, incorporated as a packed bed, or incorporated after formation of a filter rod, may be used alone in the filter element or may be incorporated with other known materials having gas phase activity such as activated carbon, flavorants and the like.

[0046] In all such filter element configurations the resistance to draw (RTD) of the filter element comprising the at least one magnetic substrate is preferably less than about 5 inches of water when measured at an air flow velocity of about 1050 cc/min.

[0047] A further embodiment provides a cigarette having a cigarette filter element, wherein the filter element comprises a filter material and a magnetic substrate. The magnetic substrate is capable of filtering (i.e., via magnetic attraction) ferromagnetic particles from the mainstream smoke of the cigarette.

[0048] Techniques for cigarette manufacture are known in the art. Any conventional or modified cigarette making technique may be used to incorporate the magnetic substrate. The resulting cigarettes can be manufactured to any known specifications using standard or modified cigarette making techniques and equipment.

[0049] Cigarettes may range from about 50 mm to about 120 mm in length. The circumference is from about 15 mm to about 30 mm in circumference, and preferably around 25 mm. The tobacco packing density is typically between the range of about 100 mg/cm.sup.3 to about 300 mg/cm.sup.3, and preferably 150 mg/cm.sup.3 to about 275 mg/cm.sup.3.

[0050] In cigarette manufacture, the tobacco is normally employed in the form of cut filler, i.e., in the form of shreds or strands cut into widths ranging from about 1/10 inch to about 1/20 inch or even 1/40 inch. The lengths of the strands range from between about 0.25 inches to about 3.0 inches. The cigarettes may further comprise one or more flavorants or other additives (e.g., burn additives, combustion modifying agents, coloring agents, binders, etc.) known in the art.

[0051] Any suitable tobacco mixture may be used for the cut filler. Examples of suitable types of tobacco materials include flue-cured, Burley, Bright, Maryland or Oriental tobaccos, the rare or specialty tobaccos, and blends thereof. The tobacco material can be provided in the form of tobacco lamina, processed tobacco materials such as volume expanded or puffed tobacco, processed tobacco stems such as cut-rolled or cut-puffed stems, reconstituted tobacco materials, or blends thereof. The tobacco can also include tobacco substitutes.

[0052] Yet another embodiment provides a method of smoking the cigarette described above, which involves lighting the cigarette to form smoke and drawing the smoke through the cigarette, wherein during the smoking of the cigarette, the at least one magnetic substrate filters ferromagnetic particles from the mainstream smoke. Generally, smoking of a cigarette involves lighting one end of the cigarette, which causes the tobacco contained therein to undergo a combustion reaction while drawing the smoke produced from the combustion reaction through the mouth end of the cigarette. A cigarette can be smoked by other means, however, such as by using an electrical heater as described, for example, in commonly-assigned U.S. Pat. No. 6,053,176; 5,934,289; 5,591,361 or 5,322,075, each of which is incorporated herein by reference in its entirety. In embodiments where the magnetic substrate is an electromagnet, an electrical heated can be used to delivery an electric current to the electromagnet in order to magnetize the electromagnet.

[0053] The following examples are illustrative. In an embodiment, magnetic beads can be incorporated into the filter material of the cigarette filter element itself. This embodiment is illustrated in FIG. 1, which shows a cigarette 2 comprised of a tobacco rod 4 and a filter element 6. The filter element 6 can comprise a tube or solid piece of material such as cellulose acetate fibers 8 having magnetic beads 10 dispersed therein. The magnetic beads can be supported by the cellulose acetate fibers. The tobacco rod 4 and the filter element 6 can be joined together with tipping paper (not shown).

[0054] In a further embodiment, magnetic beads can be incorporated into the filter element as a gas permeable bed. FIG. 2 shows a cigarette 2 comprised of a tobacco rod 4 and filter element 6. This arrangement is similar to that of FIG. 1 except the magnetic beads 10 are incorporated in a space 20 of the filter element. Preferably, space 20 is free of cellulose acetate. As in Example 1, the tobacco rod 4 and filter element 6 can be joined together with tipping paper (not shown).

[0055] Another exemplary embodiment of a cigarette is shown in FIG. 3. Cigarette 2 comprises tobacco rod 4 and filter element 6. The filter element further comprises at least one magnetic ring 30 that is disposed radially around the filter rod. The thickness of the magnetic ring is preferably about 1 mm, and can be any suitable axial length that is less than the length of the filter rod. The tobacco rod 4 and the filter element 6 can be joined together with tipping paper (not shown). Further, the filter element 6 may include a filter overwrap (not shown). Preferably the magnetic ring is external to the filter rod and the filter overwrap is wrapped around both the filter rod and the magnetic ring.

[0056] Other exemplary embodiments of a cigarette are shown in FIGS. 4-5. Cigarette 2 comprises tobacco rod 4 and filter element 6. In FIG. 4 the filter element further comprises magnetic rods 40 that are arranged axially along the length of the filter element. In FIG. 5 the filter element further comprises magnetic rods 50 that are arranged axially along the length of the filter element. In FIG. 4, the magnetic rods are external to the filter rod 44 and a filter overwrap 46 is wrapped around both the filter rod and the magnetic rods. In FIG. 5, the magnetic rods 50 are disposed axially within the filter rod such that the filter material substantially surrounds the magnetic rods.

[0057] A further exemplary embodiment of a cigarette comprising a magnetic mesh is shown in FIG. 6. Cigarette 2 comprises tobacco rod 4 and a magnetic mesh 60 external to the filter rod. A filter overwrap is preferably wrapped around both the filter rod and the magnetic mesh.

[0058] A magnetic substrate, such as one or more magnetic rods, can be incorporated into the filter material such that the filter material substantially surrounds the magnetic substrate.

[0059] A magnetic substrate may be incorporated into more than one component of a filter element such as by being incorporated into a void space as a bed of packed particles and being incorporated around the filter rod as a sleeve or ring.

[0060] The size, distribution and position of the at least one magnetic substrate incorporated in the filter element either by way of incorporation directly into and/or on filter material can be determined through routine experimentation from the amount of ferromagnetic constituents in the tobacco smoke, the amount of constituents to be removed from the mainstream smoke (e.g., trapped by the magnetic substrate in the filter element), and the magnetic strength of the magnetic substrate.

[0061] A still further embodiment relates to a method of making a filter element comprising a magnetic substrate. The method comprises providing a filter material and plug wrap material; incorporating at least one magnetic substrate in and/or on at least one of the filter material and plug wrap material; and wrapping the filter material in the plug wrap material to form the filter element.

[0062] In preferred embodiments the magnetic substrate can be incorporated in the filter material prior to forming the filter material into the filter rod or after forming the filter material into the filter rod. For example, the at least one magnetic substrate can be formed around (e.g., crimped around) and/or on an exterior surface of the filter rod prior to wrapping the filter rod in the plug wrap.

[0063] Provided is a filter material to which a magnetic substrate is incorporated in, on and/or around to form the filter element. The magnetic substrate can be incorporated in and/or on the filter material used to form a filter rod, or the magnetic substrate can be incorporated on and/or around filter material that has already been formed into a filter rod. Optionally, the filter element can be wrapped in paper and attached to a tobacco rod such as via tipping paper to form a filter cigarette. The magnetic substrate can filter via magnetic attraction ferromagnetic particles from the mainstream smoke of a cigarette comprising the magnetic filter element.

[0064] While preferred embodiments have been described, it is to be understood that variations and modifications may be resorted to as will be apparent to those skilled in the art. Such variations and modifications are to be considered within the purview and scope of the claims appended hereto.

[0065] All of the above-mentioned references are herein incorporated by reference in their entirety to the same extent as if each individual reference was specifically and individually indicated to be incorporated herein by reference in its entirety.

Claims

1. A filter element adapted to be incorporated into a filter cigarette wherein the filter element comprises a filter material and at least one magnetic substrate.

2. The filter element of claim 1, wherein the at least one magnetic substrate is selected from the group consisting of a disc, ring, ribbon, mesh, rod, cylinder and spheroid and has at least one dimension of greater than about 1 mm or greater than about 2 mm.

3. The filter element of claim 1, wherein the at least one magnetic substrate consists essentially of a ferrite magnet, a neodymium iron boron magnet, a samarium cobalt magnet, an aluminum nickel cobalt magnet or an electromagnet.

4. The filter element of claim 1, wherein the at least one magnetic substrate comprises sintered material which is at least 50% dense or at least 90% dense.

5. The filter element of claim 1, wherein the at least one magnetic substrate has a Curie temperature of at least about 300.degree. C. and/or a magnetic field strength effective to attract ferromagnetic and/or nanoscale particles being carried by the mainstream smoke of a cigarette comprising the filter element.

6. The filter element of claim 1, wherein the filter material is wrapped in plug wrap and the at least one magnetic substrate is a ring disposed on an inner surface of the plug wrap.

7. The filter element of claim 1, wherein the at least one magnetic substrate is (a) incorporated in the filter material (b) is non-homogeneously dispersed throughout the filter material, and/or (c) is formed at least partially around the filter material.

8. The filter element of claim 1, wherein the filter material is wrapped in plug wrap and the at least one magnetic substrate is disposed on an inner surface of the plug wrap and/or the at least one magnetic substrate is adhered to an inner surface of the plug wrap with an adhesive.

9. The filter element of claim 1, wherein the at least one magnetic substrate is incorporated into one or more filter parts selected from the group consisting of a shaped paper insert, a plug, a space between plugs, cigarette filter paper, a cellulose acetate sleeve, a polypropylene sleeve and a free-flow sleeve.

10. The filter element of claim 1, wherein the resistance to draw through the filter element is less than about 5 inches of water at an air flow velocity of about 1050 cc/min.

11. The filter element of claim 1, wherein the filter element comprises a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, a free-flow filter or combinations thereof, wherein the filter material is selected from the group consisting of cellulose ester fibers, regenerated cellulose, polyamide fibers, polyimide fibers, acrylic fibers, polyester fibers, polycarbonate fibers, polyethylene fibers, polyvinyl chloride fibers, filamentary polyolefin materials, polypropylene fibers, wood pulp fibers, cotton, flax, jute, wool, silk, ramie, protein fibers, paper and mixtures thereof.

12. The filter element of claim 1, wherein the filter element further comprises at least one additive, wherein the additive is selected from the group consisting of an adsorbent, flavorant and catalyst.

13. A cigarette comprising the filter element of claim 1.

14. The cigarette of claim 13, wherein the at least one magnetic substrate is adapted to reduce the amount of ferromagnetic particles entrained in the mainstream smoke of the cigarette by at least 10% and/or to change the chemical composition of mainstream smoke that flows through the filter element.

15. The cigarette of claim 13, wherein the cigarette comprises a tobacco rod wrapped in cigarette paper, said tobacco rod attached to the filter element with tipping paper, and the at least one magnetic substrate is incorporated axially between the filter material and the tobacco rod.

16. The cigarette of claim 15, wherein the tobacco rod and/or cigarette paper further comprises nanoscale and/or ferromagnetic particles.

17. A method of making a cigarette filter element comprising at least one magnetic substrate, comprising: providing a filter material and plug wrap material; forming the filter material into a filter rod; incorporating the at least one magnetic substrate in and/or on at least one of the filter rod and plug wrap material; and wrapping the filter rod in the plug wrap material to form the filter element.

18. The method of claim 17, wherein the magnetic substrate is incorporated in the filter material prior to forming the filter material into the filter rod.

19. The method of claim 17, comprising forming the at least one magnetic substrate (a) at least partially around the filter rod prior to wrapping the filter rod in the plug wrap, (b) on an exterior surface of the filter rod prior to wrapping the filter rod in the plug wrap, and/or (c) on an interior surface of the plug wrap prior to wrapping the filter rod in the plug wrap.