US20040134631A1

US20040134631A1 - Smoking article wrapping materials comprising ultrafine particles

Info

Publication number: US20040134631A1
Application number: US10/342,618
Authority: US
Inventors: Evon Crooks; Stephen Sears; Stephen Cole; Chandra Banerjee
Original assignee: Individual
Current assignee: RJ Reynolds Tobacco Co
Priority date: 2003-01-15
Filing date: 2003-01-15
Publication date: 2004-07-15

Abstract

The present invention provides wrapping materials suitable for use with smoking articles, the wrapping materials comprising ultrafine particles. The present invention is described with reference to a cigarette having a wrapping material comprising ultrafine particles. The ultrafine particles may be distributed in regions throughout the wrapping material in the form of patterns including longitudinal or circumferential bands.

Description

FIELD OF THE INVENTION

The present invention relates generally to smoking articles, including cigarettes, and more particularly to wrapping materials for smoking articles. The wrapping materials of the present invention comprise ultrafine particles. The ultrafine particles may comprise metal oxides and/or ultrafine particles of other chemical structures.

BACKGROUND OF THE INVENTION

Cigarettes, cigars and pipes are popular smoking articles that use tobacco in various forms. Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge, roll or column of smokable material such as shredded tobacco (e.g., in cut filler form) surrounded by a paper wrapper thereby forming a so-called “tobacco rod.”

Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element includes cellulose acetate tow circumscribed by plug wrap. Certain cigarettes incorporate a filter element having multiple segments, and one of those segments can comprise activated charcoal particles. Typically, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material referred to as “tipping paper”. It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air.

Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) 1999. Various properties of paper materials used for cigarette manufacture, and of cigarettes manufactured using those papers, are set forth in Durocher, TJI, 188-194 (3/1985).

Cigarettes and cigarette-like tobacco articles are employed by the smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.

During the time that the cigarette is not being drawn upon by the smoker, it remains burning. In this state, the cigarette is often referred to as smoldering. In order to reduce the propensity of a smoldering cigarette left unattended to ignite other materials, cigarettes may be designed to self extinguish when not being actively smoked. The abililty/inability of a smoldering cigarette to ignite another material is referred to as the cigarette's ignition propensity.

Numerous attempts have been made to control the manner that a cigarette burns when that cigarette is not drawn upon. See, for example, U.S. Pat. No. 2,666,437 to Lattof; U.S. Pat. No. 3,030,963 to Cohn; U.S. Pat. No. 4,146,040 to Cohn, U.S. Pat. No. 4,453,553 to Cohn; U.S. Pat. No. 4,489,650 to Weinert; U.S. Pat. No. 4,489,738 to Simon and U.S. Pat. No. 4,615,345 to Durocher. The disclosure of each of these patents is incorporated herein in full by reference.

In addition, attempts have been made to alter the composition of cigarette smoke drawn through a cigarette. An example is described in US Pat. Publication No. 20020014453, to Lilly et al., the disclosure of which is incorporated herein by reference.

Cigarette paper wrappers for the preparation of tobacco rods are described in U.S. Pat. No. 5,878,754 to Peterson et al.; U.S. Pat. No. 5,103,844 to Hayden et al.; U.S. Pat. No. 5,060,675 to Milford et al.; U.S. Pat. No. 4,998,541 to Perfetti et al.; U.S. Pat. No. 4,805,644 to Hampl, Jr. et al.; U.S. Pat. No. 4,461,311 to Mathews et al.; U.S. Pat. No. 4,450,847 to Owens; U.S. Pat. No. 4,420,002 to Cline; and U.S. Pat. No. 4,231,377 to Cline et al. The disclosure of each of these patents is incorporated herein in full by reference.

Banded paper wrapping materials that are used for cigarette manufacture possess segments defined by the composition, location and properties of the various materials within those wrapping materials. Numerous references contain disclosures relating to various banded wrapping material configurations. See, for example, U.S. Pat. No. 1,996,002 to Seaman; U.S. Pat. No. 1,999,222 to Wienberger; U.S. Pat. No. 2,013,508 to Seaman; U.S. Pat. No. 4,452,259 to Norman et al.; U.S. Pat. No. 4,889,145 to Adams et al.; U.S. Pat. No. 5,417,228 to Baldwin et al.; U.S. Pat. No. 5,878,753 to Peterson et al., U.S. Pat. No. 5,878,754 to Peterson et al.; and U.S. Pat. No. 6,198,537 to Bokelman et al.; US Pat. Application 2002/0139381 to Peterson et al.; and PCT WO O2/37991 and PCT WO O2/55294. Methods for manufacturing banded-type wrapping materials have been proposed. See, for example, U.S. Pat. No. 4,739,775 to Hampl, Jr.; U.S. Pat. No. 4,945,932 to Mentzel et al.; U.S. Pat. No. 5,474,095 to Allen et al.; and PCT WO O2/44700 and PCT WO O2/055294. Banded papers having segments of paper, fibrous cellulosic material, or particulate material adhered to a paper web also have been proposed. See, U.S. Pat. No. 5,191,906 to Myracle, Jr.; U.S. Pat. No. 5,263,999 to Baldwin et al.; U.S. Pat. No. 5,417,228 to Baldwin et al. and U.S. Pat. No. 5,450,863 to Collins et al.; and US Pat. Application 2002/0092621 to Suzuki.

It would be desirable for the cigarette manufacturers to have the means to modify the performance attributes of a cigarette utilizing alterations to the wrapping material of the tobacco rod of that cigarette.

SUMMARY OF THE INVENTION

The present invention relates to a wrapping material for smoking articles, for example cigarettes, and to smoking articles comprising the wrapping material. The wrapping material is useful for smoking articles that deliver good smoking flavor, pleasure and satisfaction.

In one aspect the present invention provides a wrapping material for a tobacco article the wrapping material comprising ultrafine particles, for example nanoparticles. The ultrafine particles may be used to control the rate of combustion of the wrapping material, the rate of combustion in the tobacco article, modifying heat transfer characteristics or for other purposes.

In an embodiment, a wrapping material of the present invention comprises ultrafine particles distributed in a manner to provide substantially full coverage of the wrapping material by ultrafine particles. As used herein “full coverage”, or “fully covered”, refers to a distribution of ultrafine particles, at a selected weight per unit area, for example grams per square meter, throughout the surface of wrapping material. Full coverage may also include one and/or both sides of the wrapping material depending on the performance characteristics desired, for example in a cigarette comprising the wrapping material. A cigarette comprising the wrapping material of this type of embodiment will be fully covered by nanoparticles which may be in intimate contact with the tobacco portion of the cigarette.

In other embodiments, portions of the wrapping material comprise ultrafine particles distributed to provide full coverage. For example, one side of the wrapping material may be fully covered. Alternatively, a portion of the wrapping material designed to be positioned near the burning end or the mouth end of a smoking article, or both, may be fully covered. In these and other embodiments, the ultrafine particles may be incorporated in the wrapping material in the form of patterns, bands or may be distributed in substantially random fashion in regions of the wrapping material, and may be incorporated to provide full coverage. The regions/portions comprising ultrafine particles may be selected such that they advantageously modify performance attributes of the smoking article.

As used herein the terminology ultrafine particle refers to particles having dimensions less than 10,000 nanometers, including nanoparticles and slightly larger particles. The term nanoparticle is generally used to indicate particles with dimensions less than 100 nanometers (one nanometer is one billionth of a meter).

The composition of ultrafine particles suitable for use in the present invention, includes but is not limited to, metal oxides, ceramics, carbon containing compositions, polymeric compositions, semiconductor compositions and the like. The ultrafine particles may be doped or coated. Further details relating to the composition of ultrafine particles are set forth below.

Embodiments of the present invention include, but are not limited to embodiments: exploiting the sintering properties of ultrafine particles to form zones of reduced oxygen access and/or altered thermal properties; catalyzing reactions in the burning cigarette that modify the combustion process; exploiting the ability of ultrafine particles to alter combustion (e.g., in conjunction with water) and/or modifying the gross physical properties of the smoking articles (e.g. cigarettes) for example the ash structure and/or cigarette structure (e.g. cross-sectional shape, longitudinal shape).

The wrapping material may comprise a cellulosic web, for example flax or wood pulp fibers. The wrapping materials may further comprise a filler material (e.g. an inorganic, essentially water insoluble material, such as calcium carbonate in particulate form) and/or a burn additive, the type and selection of either being within the skill of one of ordinary skill in the art as illustrated by the foregoing referenced patents.

In embodiments of the present invention the ultrafine particles may be incorporated in, embedded in, or printed or painted on the wrapping material by any known method. Ultrafine particles may be incorporated in the wrapping material during production of the wrapping material, may be applied to the wrapping material after the wrapping material is produced and/or may be applied to the wrapping material during production of a smoking article.

In an embodiment of the present invention, ultrafine particles are added as part of a filler during production of the wrapping material. In another embodiment of the present invention, ultrafine particles are applied as a film to existing wrapping material. In an alternative embodiment of the present invention ultrafine particles are incorporated with other materials as part of the wrapping material production process. Ultrafine particles may also be utilized to coat cellulose fibers used in a wrapping material.

In other embodiments of the present invention, ultrafine particles are embedded in or printed or painted on the wrapping material. Ultrafine particles may be applied to the wrapping material by plasma deposition or electrostatic precipitation techniques. In an embodiment, ultrafine particles may be applied utilizing intaglio processes or gravure coating techniques. Other techniques for the coating formulation to the wrapping material include blade coating, air-knife coating, roll-coating and shaft coating techniques. Alternatively and/or additionally, the ultrafine particles may be applied by spraying, ink jet coating, or other similar coating techniques. A printed wrapping material is provided with a pattern such as is provided by application of at least one additive material to a formed wrapping material. The pattern is applied to the wrapping material in a so-called offline fashion (i.e., offline relative to the manufacture of that wrapping material).

The foregoing techniques are described in more detail below and in patent references cited herein.

The ultrafine particles may be incorporated in a wrapping material in the form of bands, strips, patterns etc., or may be distributed in various sections of the wrapping material. Ultrafine particles can also be placed in seam line adhesives. Details relating to application of additives to wrapping materials, including application in patterns are set forth in the commonly assigned co-pending patent application entitled “Wrapping Materials for Smoking Articles” by Stokes et al., U.S. patent application Ser. No. 10/303,648 filed Nov. 25, 2002, the disclosure of which is hereby incorporated herein by reference.

Wrapping materials of the present invention are useful as wrappers in the manufacture of cigarettes and other smoking materials. In a further embodiment the present invention provides a smoking article comprising a wrapping material of the present invention circumscribing a charge of material, for example a smoking material, to form a smoking article comprising a rod. This embodiment includes a cigarette. If the material in the smoking article is designed to burn, the wrapping material may burn along with the material when the cigarette is smoked. In other embodiments of smoking articles of the present invention, the smoking material will not be designed to burn, or only a portion of the material may be designed to burn. In these embodiments, the wrapping material may remain intact, or a portion of the wrapping material may burn.

A smoking article of the present invention may further comprise a filter element and a tipping material. The filter element may be positioned adjacent to one end of the smokable rod, the tipping material circumscribing the filter element and an adjacent region of the smokable rod. Smoking articles having filters comprising cellulose acetate filter tow are particularly preferred. Smoking articles having filters comprising cellulose acetate filter tow and carbon are also preferred. The smoking articles are also preferably air diluted.

In embodiments of the present invention wherein the charge of material comprises tobacco, the cigarettes when smoked preferably yield an ash which is cohesive and exhibits good integrity. In addition, the cigarettes preferably tend to burn in such a manner at a desirable rate, in order that such cigarettes provide a desirable number of puffs. Further preferred cigarettes do not provide an undesirable off-taste and off-aroma to the mainstream and sidestream smoke generated thereby, and are capable of generating relatively low levels of visible sidestream smoke.

An advantage of the present invention is that in certain embodiments of the present invention wrapping materials comprising ultrafine particles may have altered physical and/or chemical properties during burning in comparison to untreated wrapping materials. As a result, smoking articles comprising wrapping materials of the present invention may be designed with desirable properties for particular applications.

Another advantage of the present invention is that in certain embodiments of the present invention ultrafine particles do not adversely affect the porosity of wrapping material prior to burning.

A further advantage of the present invention is that in certain embodiments of the present invention the ultrafine particles have a minimal affect on the overall nature of smoke chemistry, particularly the flavor chemistry of the smoke.

In preferred embodiments of the present invention, the ultrafine particles have minimal adverse affect on the appearance and porosity of the wrapping material, and minimal adverse affect on the on the appearance, nature of the smoke and flavor of a smoking article comprising a wrapping material of the present invention.

An additional advantage of the present invention is that in certain embodiments of the present invention, ultrafine particles may be applied to portions, including all portions, of a wrapping material using existing equipment utilized in cigarette paper making processes and/or in cigarette production processes. The ultrafine particles may be applied to wrapping materials on line as part of a paper making process and/or a cigarette making process, and/or may be applied offline during either or both processes.

The present invention also provides methods for reducing ignition propensity in a smoking article. The methods of the present invention utilize a wrapping material of the present invention. Thus, in a general sense, the present invention provides methods for reducing ignition propensity in a smoking article having a wrapping material, the methods comprising utilizing a wrapping material of the present invention as at least one layer of wrapping material for the smoking article. For the purposes of the present invention “reducing ignition propensity in a smoking article” refers to smoking articles that when tested utilizing the methodologies described hereinafter meet those extinction criteria set forth hereinafter.

Embodiments of the methods of the present invention correspond to embodiments of the wrapping materials of the present invention.

The advantages of the methods of the present invention include the aforementioned advantages associated with wrapping materials of the present invention.

Further details relating to the present invention, and its advantages, are set forth in the following sections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a smoking article of the present invention. [0037]
FIG. 2 is an exploded view of the embodiment depicted in FIG. 1. [0038]
FIG. 3 is a longitudinal sectional view of an additional embodiment of a cigarette of the present invention. [0039]
FIG. 4 is a longitudinal sectional view of a further embodiment of a cigarette of the present invention.[0040]

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides wrapping materials, suitable for use in smoking articles, the wrapping materials comprising ultrafine particles. The present invention also provides smoking articles comprising a wrapping material incorporating ultrafine particles. [0041]
In a further aspect the present invention provides a method for modifying the performance properties of a tobacco article having a wrapping material, the method comprising incorporating ultrafine particles in intimate contact with the wrapping material. [0042]
Thus, in an aspect, the present invention provides a method for reducing the ignition propensity in a smoking article having a wrapping material comprising incorporating ultrafine particles in at least one region of the wrapping material. The region may comprise substantially all of the wrapping material. In addition, the region may be fully covered by ultrafine particles. [0043]
In embodiments of a method of the present invention, the wrapping material comprises ultrafine particles in a plurality of regions. The ultrafine particles may be distributed in patterns as described hereinafter. [0044]
In an embodiment, the present invention provides a wrapping material, for example a cigarette paper, the wrapping material comprising ultrafine particles in intimate contact with a selected region of the wrapping material. The regions are preferably selected such that the ultrafine particles modify the performance characteristics of the smoking article. The regions may include areas near either end of the smoking article. Preferably, a plurality of ultrafine particles are distributed substantially throughout a wrapping material in a plurality of regions and/or in a selected pattern. A plurality of ultrafine particles may be distributed in the form of a band, or a plurality of bands radially spaced around the circumference of the wrapping material when the wrapping material is formed into a rod. In a further embodiment a plurality of ultrafine particles are distributed in the form of at least one longitudinal axial band extending at least a portion of the length of the wrapping material, and in particular extending at least a portion of a rod formed from the wrapping material. In another embodiment, the wrapping material comprises a glue utilized to seal the wrapping material and the glue comprises a plurality of ultrafine particles. In other embodiments of the present invention the ultrafine particles may be randomly distributed in selected regions of the wrapping material, preferably in defined patterns. [0045]
An embodiment of the present invention is a cigarette. In a first aspect, the present invention provides a cigarette comprising a rod of smokable material contained in a circumscribing paper wrapping material in intimate contact with ultrafine particles. The cigarette may comprise a plurality of ultrafine particles distributed throughout the paper wrapping material. In certain embodiments of the present invention, the smokable material is substantially free of ultrafine particles. [0046]
Ultrafine particles comprise metal oxides, including, but not limited to: silica (SiO[0047] ₂), magnesium oxide (MgO), titania (TiO₂), alumina (e.g. Al₂O₃), iron oxide (e.g. FeO, Fe₃O₄and Fe₂O₃), hydrated aluminum oxide (AIOOH), zinc oxide (ZnO), ceria (CeO₂) and zirconia (ZrO₂). Ultrafine particles may also comprise mixed oxides, such as indium-tin oxide (e.g. In₂O₃-SnO₂or ITO) and antimony-tin oxide (ATO), as well as titanates, particularly barium titanate (BaTiO₃). As will be understood by those of ordinary skill in the art, the valence states of the metal ions in the foregoing metal oxides can vary, thus the present invention should not be construed as limited to the particular examples of metal oxides set forth above. In addition, ultrafine particles may comprise other materials including carbon, various complex oxides, metals, polymers, semiconductors and nonoxide ceramics. Further, the ultrafine particles may be doped with platinum, palladium and/or other catalytic materials.
Embodiments of the present invention may comprise a plurality of ultrafine particles having a similar composition, e.g. comprising the same metal oxide. Alternatively, embodiments of the present invention may comprise a mixture of ultrafine particles having different compositions, e.g. a mixture of various metal oxides. [0048]
Ultrafine particles may be produced by a variety of methods including sol-gel synthesis, inert gas condensation, mechanical alloying or high-energy ball milling, plasma synthesis, and electrodeposition. Using such methods, ultrafine particles can be produced in various symmetric shapes, such as spheres, cylinders, prisms, cubes, tetrapods and amorphous clusters. In embodiments of the present invention, the physical properties of ultrafine particles, including for example, their electrical, optical, chemical, mechanical, and magnetic properties, may be selectively controlled for example by engineering the size, morphology, and/or composition of the ultrafine particles. The resulting materials may have enhanced or entirely different properties from their parent materials. [0049]
Representative types of ultrafine particles and materials suitable for use in the present invention are of the type, and may be produced by the methods, described in U.S. Pat. No. 5,006,248 to Anderson et al., U.S. Pat. No. 5,096,745 to Anderson et al., U.S. Pat. No. 5,269,926 to Webster et al., U.S. Pat. No. 6,503,475 to McCormick et al., U.S. Pat. No. 6,472,459 to Morales et al., U.S. Pat. No. 6,467,897 to Wu et al., U.S. Pat. No. 6,479,028 to Kaner et al., U.S. Pat. No. 6,479,146 to Caruso et al., and U.S. Pat. No. 6,479,156 to Schmidt et al., U.S. Pat. No. 5,169,576 to Anderson et al. and US Published Pat. Applications 2002/0194958 to Lee et al., 2002/014453 to Lilly Jr., et al., 2003/0000538 to Bereman et al., 2002/0167118, 2002/0172826 and 2002/0127351, the disclosure of each patent and published application being incorporated herein by reference. [0050]
In addition to the assignees of some of the aforementioned patents and patent applications, ultrafine particles are commercially available from sources including Nanopowder Enterprise Inc. of Piscataway, N.J. 08854. [0051]
Ultrafine particles may be applied to a wrapping materials during production of the wrapping material. In a typical procedure, ultrafine particles are applied in solution at varying pH levels, for example at a pH range of 2 to 12. The particles may be applied such that their orientation on the cigarette would include full coverage in selected regions of the cigarette, longitudinal along the tobacco column and/or in axial bands. [0052]
The ultrafine particles may be applied to either side or both sides of the wrapping material (e.g., to either the “felt” side of the wrapping material or the “wire” side of the wrapping material). Most preferably, the coatings are applied to the “wire” side of the wrapping material. [0053]
An advantage of the present invention is that ultrafine particles may be applied in a controlled manner to achieve uniform concentrations in regions of the wrapping material or throughout the wrapping material. [0054]
The ultrafine particles may be applied to a wrapping material to form an embodiment of the present invention utilizing a size press paper marking machine. Alternatively, or in addition, ultrafine particles may be applied utilizing print press technology either on line in a cigarette forming process or off line. It is also possible to incorporate the application of ultrafine particles to a wrapping material as part of the wrapping material formation process (e.g. paper making process). In general, ultrafine particles may be applied by spraying, dipping, painting on or other methods known to those of ordinary skill in the art for applying particulate materials to other solid materials. By way of example, ultrafine particles may be applied using the general techniques for applying compositions to wrapping materials described in U.S. patent application Ser. No. 10/326,539, entitled “Equipment and Methods for Manufacturing Cigarettes” filed on Dec. 20, 2002 by Barnes et al., the disclosure of which is incorporated herein by reference. [0055]
In an embodiment of the present invention, a wrapping material may comprise selected regions of 0.1 to 10 grams ultrafine particles per square meter of wrapping material (g/m[0056] ²), generally 0.2 to 5 g/m²more generally 0.3 to 3.0 g/m², depending on the porosity of the wrapping material. In embodiments of the present invention, the concentration of ultrafine particles may be tailored such that the wrapping material achieves a desired porosity.
The ultrafine particles may be applied onto a wrapper material in the form of a sol/powder/solution/aerosol comprising ultrafine particles such that the ultrafine particles are applied in a range of 0.4 to 40%, by weight, preferably 0.5 to 20%, by weight of wrapper material. In addition to ultrafine particles, the sol may comprise: an alcohol; water and/or solvents. The sol may also comprise additives and fillers of the type described in the patents referenced herein. [0057]
In accordance with the present invention ultrafine particles may be applied to a wrapping material and incorporated in intimate contact with the wrapping material using a printing process. For example, the ultrafine particle may be applied using intaglio processes. As such, gravure coating techniques, such as rotogravure printing techniques, are particularly preferred. Other techniques for incorporating the nanoparticles in the wrapping material include blade coating, air-knife coating, roll-coating and shaft coating techniques. Alternatively and/or additionally, the nanoparticles may be applied by spraying, ink jet coating, or other similar coating techniques. A printed wrapping material is provided with a pattern such as is provided by application of ultrafine particles to a formed wrapping material. The pattern is applied to the wrapping material in a so-called offline fashion (i.e., offline relative to the manufacture of that wrapping material). [0058]
Gravure printing techniques involve printing from the continuous surface of a metal cylinder engraved mechanically or etched chemically so as to possess minute grooves or cells below the surface of that cylinder. A typical printing cylinder surface is provided by etching a smooth, polished copper surface and plating that etched surface with chrome. Those recessed cells or grooves hold liquid (or liquid dispersion) formulations form impressions, layers or “bumps” to be deposited onto the desired location of a substrate, such as a continuous web of paper wrapping material. Rotogravure printing presses have been commercially available from Bobst Champlain, Inc.; from Cerutti S.p.A.; from Rotomek, S.p.A.; from Intra-Roto, Inc.; as Merkur Heliostar from Wirdmoller & Holscher, and KBA TR 7B from Albert-Frankenhal AG. Gravure printing techniques are described in [0059] Pocket Pal, published by International Paper Company (1970); Scarlett et al., What the Printer Should Know About Ink (1984); and Gravure, Process and Technology, Grav. Educ. Fdn. and Grav. Assoc. Amer. (1991). Thus, the selection and operation of gravure printing equipment will be readily apparent to one skilled in the art of printing. See, for example, US Pat. Application 2002/0139381 to Peterson et al. Equipment and techniques for applying coatings and inks to paper wrapping materials suitable for the manufacture of tobacco rods for cigarettes are set forth in U.S. Pat. No. 5,060,675 to Milford et al.; U.S. Pat. No. 5,878,753 to Peterson et al.; U.S. Pat. No. 5,878,754 to Peterson et al.; and PCT WO O2/37991. See, also, U.S. Pat. No. 4,474,110 to Rosner.
The wrapping material of the present invention may comprise ultrafine particles in patterns having predetermined shapes. The ultrafine particles can have the form of bands, cross directional lines or bands (including those that are perpendicular to the longitudinal axis of the wrapping material), stripes, grids, longitudinally extending lines, circles, hollow circles, dots, ovals, checks, spirals, swirls, helical bands, diagonally crossing lines or bands, triangles, hexagonals, honeycombs, ladder-type shapes, zig zag shaped stripes or bands, sinusoidal shaped stripes or bands, square wave shaped stripes or bands, patterns composed of printed regions that are generally “C” or “U” shaped, patterns composed of printed regions that are generally “E” shaped, patterns composed of printed regions that are generally “S” shaped, patterns composed of printed regions that are generally “T” shaped, patterns composed of printed regions that are generally “V” shaped, patterns composed of printed regions that are generally “W” shaped, patterns composed of printed regions that are generally “X” shaped, patterns composed of printed regions that are generally “Z” shaped, or other desired shapes. Combinations of the foregoing shapes also can used to provide the printing pattern. Printing patterns incorporating certain of the foregoing shapes can be employed as the discontinuous layers of certain multi-layered printed patterns, such as multi-layered bands. [0060]
The relative sizes or dimensions of the various shapes and designs can be selected as desired. For example, shapes of ultrafine particle regions, compositions of the ultrafine particles, and/or amounts or concentrations of ultrafine particles, can change over the length of the wrapping material. The relative positioning of the printed regions can be selected as desired. For example, wrapping materials that are used for the production of cigarettes designed to meet certain cigarette extinction test criteria, the pattern most preferably has the form of spaced continuous bands that are aligned transversely or cross directionally to the longitudinal axis of the wrapping material. However, cigarettes can be manufactured from wrapping materials possessing discontinuous bands positioned in a spaced apart relationship. For wrapping materials of those cigarettes, it is most preferred that discontinuous bands (e.g., bands that are composed of a pattern, such as a series of dots, grids or stripes) cover at least about 70 percent of the surface of the band area or region of the wrapping material. [0061]
In an embodiment of the present invention, a wrapping material comprises ultrafine particles in substantially all regions of the wrapping material such that the wrapping material is substantially fully covered with ultrafine particles. [0062]
In another embodiment wrapping materials possess ultrafine particles in the form of bands that extend across the wrapping material, generally perpendicular to the longitudinal axis of the wrapping material. The widths of the individual bands can vary, as well as the spacings between those bands. Typically, those bands have widths of at least about 0.5 mm, usually at least about 1 mm, frequently at least about 2 mm, and most preferably at least about 3 mm. Typically, those bands have widths of up to about 8 mm, usually up to about 7 mm. Preferred bands have widths of about 4 mm to about 7 mm. Such bands can be spaced apart such that the spacing between the bands is at least about 10 mm; often at least about 15 mm, frequently at least about 20 mm, often at least about 25 mm, in certain instances at least about 30 mm, and on occasion at least about 35 mm; but such spacing usually does not exceed about 50 mm. [0063]
For a tobacco rod of a particular length incorporating a wrapping material possessing bands that are aligned transversely to the longitudinal axis of the wrapping material in a spaced apart relationship, the ratio of the length of the tobacco rod to the sum of the width of a band and the distance between the bands is in the range of 1 to 2, preferably about 1.1 to about 1.4, and most preferably about 1.2. [0064]
Wrapping materials possessing ultrafine particles in the form of bands may have the ultrafine particles applied in a layered form. That is, a layer of ultrafine particles is applied to the major surface of the wrapping material, and successive layers are applied to the wrapping material over all or part of each successive layer. The composition of each layer can be the same, or the compositions of the various layers can be different from one another. In certain circumstances, a hydrophobic coating is applied as the first layer to the major surface of the wrapping material; either as a band layer, a coated region, or as a layer that fully covers the surface of the wrapping material. As such, a first coating is deposited directly onto the substrate, and that coating can be effective to reduce the water absorption capabilities of that substrate. [0065]
There are several factors that determine a specific ultrafine particle pattern for a wrapping material of the present invention. It is desirable that the ultrafine particles applied to wrapping materials not adversely affect to any significant degree (i) the appearance of cigarettes manufactured from those wrapping materials, (ii) the nature or quality of the smoke generated by those cigarettes, (iii) the desirable burn characteristics of those cigarettes, or (iv) the desirable performance characteristics of those cigarettes. It also is desirable that wrapping materials having ultrafine particles applied thereto not introduce undesirable off-taste, or otherwise adversely affect the sensory characteristics of the smoke generated by cigarettes manufactured using those wrapping materials. In addition, preferred cigarettes of the present invention do not have a tendency to go out during smoking when lit cigarettes are held in the smoker's hand or when placed in an ashtray for a brief period of time. [0066]
An advantage of embodiments of the present invention is that wrapping materials of the present invention may be utilized in the production of smoking articles that meet certain cigarette extinction test criteria such as the criteria described hereinafter. In general smoking articles utilizing higher porosity wrapping materials have less tendency to self extinguish and therefore may comprise a higher percentage of ultrafine particles in embodiments of the present invention designed to meet such extinction tests. In general the concentration of ultrafine particles may be varied depending on the porosity and/or the composition of the wrapping material to achieve desired performance properties. [0067]
Wrapping materials of the present invention are useful as components of smoking articles such as cigarettes. Preferably, one layer of the wrapping material of the present invention is used as the wrapping material circumscribing the smokable material, and thereby forming the tobacco rod of a cigarette. In one regard, it is preferable that the wrapping material possesses the ultrafine particle regions located on the “wire” side thereof, and the “wire” side of that wrapping material forms the inner surface of the circumscribing wrapping material of the tobacco rod. In another regard, it is preferable that the wrapping material possesses the ultrafine particle regions located on the “felt” side thereof, as coating on the “felt” side of that wrapping material provides for a relatively great decrease in the porosity of that wrapping material for a relatively small amount of coating. The terms “wire side” and “felt side” in referring to the major surfaces of paper sheet are readily understood as terms of art to those skilled in the art of paper manufacture. [0068]
The wrapping materials of the present invention also can be used in the manufacture of tobacco rods having more than one layer of circumscribing wrapping material, such as the so-called “double wrap” tobacco rods. That is, the wrapping material of the present invention can be used as the inner wrap or the outer wrap of such double wrap tobacco rods. Exemplary cigarettes, and exemplary components, parameters and specifications thereof, are described in U.S. Pat. No. 5,220,930 to Gentry; PCT WO O2/37990 and US Pat. Application 2002/0166563. [0069]
The wrapping material that is employed in carrying out cigarette manufacture in accordance with the present invention can vary. The selection of a particular wrapping material will be readily apparent to those skilled in the art of cigarette design and manufacture. Various properties of paper wrapping materials used for cigarette manufacture, and of cigarettes manufactured using those papers, are set forth in Durocher, [0070] TJI, 188-194 (3/185).
Typical paper wrapping material base webs suitable for use as the circumscribing wrappers of tobacco rods for cigarettes comprise at least one type of fibrous material, and can include at least one filler material, in amounts that can vary. Typical base webs include about 55 to about 100, often about 65 to about 95, and frequently about 70 to about 90 percent fibrous material (which most preferably is a cellulosic material); and about 0 to about 45, often about 5 to about 35, and frequently about 10 to about 30 percent filler material (which most preferably is an inorganic material); based on the dry weight of that base web. Typical paper wrapping material base webs suitable for use as the circumscribing wrappers of tobacco rods for cigarettes have basis weights that can vary. Typical dry basis weights of base webs are at least about 15 g/m[0071] ², and frequently are at least about 20 g/m²; while typical dry basis weights do not exceed about 80 g/m², and frequently do not exceed about 60 g/m². Many preferred paper wrapping material base webs have basis weights of less than 50 g/m², and even less than 40 g/m². Certain preferred paper wrapping material base webs have basis weights between about 20 g/m²and about 30 g/m².
Typical paper wrapping material base webs suitable for use as the circumscribing wrappers of tobacco rods for cigarettes have permeabilities that can vary. Typical base webs have inherent porosities that are at least about 5 CORESTA units, usually are at least about 10 CORESTA units, often are at least about 15 CORESTA units, and frequently are at least about 20 CORESTA units. Typical base webs have inherent porosities that are less than about 200 CORESTA units, usually are less than about 150 CORESTA units, often are less than about 85 CORESTA units, and frequently are less than about 70 CORESTA units. A CORESTA unit is a measure of the linear air velocity that passes through a 1 cm[0072] ²area of wrapping material at a constant pressure of 1 centibar. See, CORESTA Publication ISO/TC0126/SC I N159E (1986). The term “inherent porosity” refers to the porosity of that paper itself to the flow of air. A particularly preferred paper wrapping material base web comprises wood pulp and calcium carbonate, and exhibits an inherent porosity of about 20 to about 50 CORESTA units.
The wrapping material comprises a fibrous material. The fibrous material can vary. Most preferably, the fibrous material comprises a cellulosic material, and the cellulosic material can be a lignocellulosic material. Exemplary cellulosic materials include flax fibers, hardwood pulp, softwood pulp, hemp fibers, esparto fibers, kenaf fibers, jute fibers and sisal fibers. Mixtures of two or more types of cellulosic materials can be employed. For example, wrapping materials can incorporate mixtures of flax fibers and wood pulp. The fibers can be bleached or unbleached. Other fibrous materials that can be incorporated within wrapping materials include microfibers materials and fibrous synthetic cellulosic materials. See, for example, U.S. Pat. No. 4,779,631 to Durocher and U.S. Pat. No. 5,849,153 to Ishino. Representative fibrous materials, and methods for making wrapping materials therefrom, are set forth in U.S. Pat. No. 2,754,207 to Schur et al; U.S. Pat. No. 5,474,095 to Allen et al.; and PCT WO 01/48318. [0073]
The wrapping material normally further comprises a filler material. Preferably, the filler material has the form of essentially water insoluble particles. Additionally, the filler material normally incorporates inorganic components. Filler materials incorporating calcium salts are particularly preferred. One exemplary filler material has the form of calcium carbonate, and the calcium carbonate most preferably is used in particulate form. See, for example, U.S. Pat. No. 4,805,644 to Hampl; U.S. Pat. No. 5,161,551 to Sanders; and U.S. Pat. No. 5,263,500 to Baldwin et al.; and PCT WO 01/48,316. Other filler materials include agglomerated calcium carbonate particles, calcium tartrate particles, magnesium oxide particles, magnesium hydroxide gels; magnesium carbonate-type materials, clays, diatomaceous earth materials, titanium dioxide particles, gamma alumina materials and calcium sulfate particles. See, for example, U.S. Pat. No. 5,109,876 to Hayden; U.S. Pat. No. 4,231,377 to Cline; U.S. Pat. No. 4,450,847 to Owens; U.S. Pat. No. 4,915,118 to Kaufman; U.S. Pat. No. 5,092,306 to Bokelman; U.S. Pat. No. 5,699,811 to Paine; U.S. Pat. No. 5,927,288 to Bensalem; U.S. Pat. No. 5,979,461 to Bensalem; U.S. Pat. No. 3,049,449 to Allegrini; 4,779,631 to Durocher; 6,138,684 to Yamazaki; U.S. Pat. No. 4,108,151 to Martin and European Pat. Application 357,359. Certain filler-type materials that can be incorporated into the wrapping materials can have fibrous forms. For example, components of the filler material can include materials such as glass fibers, ceramic fibers, carbon fibers and calcium sulfate fibers. See, for example, U.S. Pat. No. 2,998,012 to Lamm; U.S. Pat. No. 4,433,679 to Cline; PCT WO 01/41590; European Pat. Application 1,084,629 and U.S. Pat. No. 5,103,844 to Hayden et al. Mixtures of filler materials can be used. For example, filler material compositions can comprise mixtures of calcium carbonate particles and magnesium hydroxide gel, mixtures of calcium carbonate particles and calcium sulfate fibers, or mixtures of calcium carbonate particles and magnesium carbonate particles. [0074]
The base webs can be treated further, and those base webs can be treated so as to impart a change to the overall physical characteristics thereof and/or so as to introduce a change in the overall chemical composition thereof. For example, the base webs can be electrostatically perforated. See, for example, U.S. Pat. No. 4,924,888 to Perfetti et al. Representative additives, and methods for incorporating those additives to wrapping materials, are set forth in U.S. Pat. No. 5,220,930 to Gentry, which is incorporated herein by reference. See, also, U.S. Pat. No. 5,168,884 to Baldwin et al. Certain components, such as alkali metal salts, can act a burn control additives. Representative salts include alkali metal succinates, citrates, acetates, malates, carbonates, chlorides, tartrates, propionates, nitrates and glycolates; including sodium succinate, potassium succinate, sodium citrate, potassium citrate sodium acetate, potassium acetate, sodium malate, potassium malate, sodium carbonate, potassium carbonate, sodium chloride, potassium chloride, sodium tartrate, potassium tartrate, sodium propionate, potassium propionate, sodium nitrate, potassium nitrate, sodium glycolate and potassium glycolate; and other salts such as monoammonium phosphate. See, for example, U.S. Pat. No. 2,580,568 to Matthews; U.S. Pat. No. 4,461,311 to Matthews; U.S. Pat. No. 4,622,983 to Matthews; U.S. Pat. No. 4,941,485 to Perfetti et al.; U.S. Pat. No. 4,998,541 to Perfetti et al.; and PCT WO 01/08514. Certain components, such as metal citrates, can act as ash conditioners or ash sealers. See, for example, European Pat. Application 1,084,630. Other representative components include organic and inorganic acids, such as malic, levulinic, boric and lactic acids. See, for example, U.S. Pat. No. 4,230,131 to Simon. Other representative components include catalytic materials. See, for example, U.S. Pat. No. 2,755,207 to Frankenburg. Typically, the amount of chemical additive does not exceed about 1 weight percent of the dry weight of the wrapping material to which the chemical additive is applied. Exemplary flax-containing cigarette paper wrapping materials having relatively high levels of chemical additives have been available as Grade Names 512, 525, 527, 540, 605 and 664 from Schweitzer-Mauduit International. Exemplary wood pulp-containing cigarette paper wrapping materials having relatively high levels of chemical additives have been available as Grade Names 406 and 419 from Schweitzer-Mauduit International. Flavoring agents and/or flavor and aroma precursors (e.g., vanillin glucoside and/or ethyl vanillin glucoside) also can be incorporated into the paper wrapping material. See, for example, U.S. Pat. No. 4,804,002 to Herron; and U.S. Pat. No. 4,941,486 to Dube et al. [0075]
Paper wrapping materials suitable for use in carrying out the present invention are commercially available. Representative cigarette paper wrapping materials have been available as Ref. Nos. 419, 454, 456, 460 and 473 Ecusta Corp.; Ref. Nos. Velin 413, Velin 430, VE 825 C20, VE 825 C30, VE 825 C45, VE 826 C24, VE 826 C30 and 856 DL from Miquel; Tercig LK18, Tercig LK24, Tercig LK38, Tercig LK46 and Tercig LK60 from Tervakoski; and Velin Beige 34, Velin Beige 46, Velin Beige 60, and Ref. Nos. 454 DL, 454 LV, 553 and 556 from Wattens. Exemplary flax-containing cigarette paper wrapping materials have been available as Grade Names 105, 114, 116, 119, 170, 178, 514, 523, 536, 520, 550, 557, 584, 595, 603, 609, 615 and 668 from Schweitzer-Mauduit International. Exemplary wood pulp-containing cigarette paper wrapping materials have been available as Grade Names 404, 416, 422, 453, 454, 456, 465, 466 and 468 from Schweitzer-Mauduit International. [0076]
Wrapping materials for the tobacco rod can have a wide range of permeabilities or, as set forth above, porosities. The wrapping material may include a series of perforations, e.g. electrostatic perforations, which extend in a linear fashion along the longitudinal length of thereof. Alternatively, other configurations, such as a random perforation pattern, can be provided. The size, number and relative positioning of the individual perforations can vary depending upon the desired characteristics of the cigarette which has the wrapping material incorporated therein. [0077]
Reference is made below to specific embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each embodiment is provided by way of explanation of the invention, not as a limitation of the invention. In fact it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. [0078]
The invention is described in more detail with reference to a particular tobacco article, namely a cigarette utilizing a circumscribing paper wrapping material., As will be understood by those of ordinary skill in the art, however, the principals of the present invention apply to other tobacco articles such as cigars wherein ultrafine particles may be incorporated in a natural based wrapping material, for example a tobacco leaf material. [0079]
FIG. 1 depicts an embodiment of a wrapping material and smoking article of the present invention. As shown in FIG. 1, [0080] cigarette 10, includes a generally cylindrical rod 15 of a charge or roll of smokable filler material 20 contained in a circumscribing wrapping material 25. The rod 15 is conveniently referred to as a “smokable rod” or a “tobacco rod”. The ends of the tobacco rod are open to expose the smokable filler material.
The [0081] cigarette 10 normally includes a filter element 30 or other suitable mouthpiece positioned adjacent one end of the tobacco rod 15 such that the filter element and tobacco rod are axially aligned in an end-to-end relationship, preferably abutting one another. Filter element 30 has a generally cylindrical shape, and the diameter thereof is essentially equal to the diameter of the tobacco rod. The ends of the filter element are open to permit the passage of air and smoke therethrough. The filter element 30 includes filter material 35 which is overwrapped along the longitudinally extending surface thereof with circumscribing plug wrap material 40. The filter element can have two or more filter segments, and/or flavor additives incorporated therein.
The [0082] filter element 30 is attached to the tobacco rod 15 by tipping material 45 which circumscribes both the entire length of the filter element and an adjacent region of the tobacco rod. The inner surface of the tipping material 45 is fixedly secured to the outer surface of the plug wrap 40 and the outer surface of the wrapping material 25 of the tobacco rod, using a suitable adhesive. A ventilated or air diluted smoking article is provided with an air dilution means, such as a series of perforations 50, each of which extend through the tipping material and plug wrap.
The wrapping [0083] material 25 has a width which is equal to the circumference of the cigarette plus the lap zone of the glue line which ultimately results during cigarette manufacture.
A conventional automated cigarette rod making machine useful for manufacturing cigarettes of the present invention is of the type commercially available from Molins PLC or Hauni-Werke Korber & Co. KG. For example, cigarette rod making machines of the type known as Mk8 (commercially available from Molin PLC) or PROTOS (commercially available from Hauni-Werke Korber & Co. KG) can be employed, and can be suitably modified if desired. A description of a PROTOS cigarette making machine is provided in U.S. Pat. No. 4,474,190, at col. 5, line 48 through col. 8, line 3, which is incorporated herein by reference. Types of equipment suitable for the manufacture of cigarettes also are set forth in U.S. Pat. No. 4,844,100 to Holznagel; U.S. Pat. No. 5,156,169 to Holmes et al. and U.S. Pat. No. 5,191,906 to Myracle, Jr. et al.; and PCT WO O2/19848. Designs of various components of cigarette making machines, and the various materials used to manufacture those components, will be readily apparent to those skilled in the art of cigarette making [0084]
In an embodiment of the present invention, a wrapping material comprises ultrafine particles. As will be realized from the foregoing description, the actual size of a typical ultrafine particle may be less than 100 nm, therefore the ultrafine particles would not be visible on a wrapping material. Referring to FIG. 2, wrapping [0085] material 25, may comprise axial bands of ultrafine particles 70, 72, 74, 76 etc.
In another aspect the present invention includes embodiments of cigarettes comprising multiple layers of wrapping material. Ultrafine particles may be incorporated into one or more of the layers of wrapping material in the configurations described herein (axial, longitudinal, etc.). Examples of cigarettes with multiple layers of wrapping material are described in U.S. Pat. No. 5,220,930 to Gentry, the disclosure of which is incorporated herein by reference. [0086]
Cigarettes of the present invention possessing tobacco rods manufactured using certain appropriately treated wrapping materials of the present invention, when tested using the methodology set forth in the Cigarette Extinction Test Method by the National Institute of Standards and Technology (NIST), Publication 851 (1993) using 10 layers of Whatman No. 2 filter paper, meet criteria requiring extinction of greater than about 50 percent, preferably greater than about 75 percent, and most preferably about 100 percent, of cigarettes tested. Preferably, each cigarette possesses at least one band located in a region of its tobacco rod such that the band is capable of providing that cigarette with the ability to meet those cigarette extinction criteria. [0087]
For an exemplary full flavor cigarette having a tobacco rod length of about 63 mm and a filter element length of about 21 mm, cross directional bands of about 6 mm width can be spaced at about 20 mm intervals on the wrapping materials used to manufacture those cigarettes. Alternatively, for those types of cigarettes, bands of about 4 mm width can be spaced at about 22 mm intervals on the wrapping materials used to manufacture those cigarettes. Alternatively, for those types of cigarettes, bands of about 6 mm width can be spaced at about 39 mm intervals. For an exemplary full flavor cigarette having a tobacco rod length of about 70 mm and a filter element length of about 30 mm, cross directional bands of about 6 mm width can be spaced at about 44 mm intervals on the wrapping materials used to manufacture those cigarettes. For an exemplary ultra low tar cigarette having a tobacco rod length of about 57 mm and a filter element length of about 27 mm, cross directional bands of about 7 mm width can be spaced at about 20 mm intervals. Alternatively, for those types of cigarettes, bands of about 6 mm width can be spaced at about 33 mm intervals, or at about 39 mm intervals, on the wrapping materials used to manufacture those cigarettes. For an exemplary ultra low tar cigarette having a tobacco rod length of about 68 mm and a filter element length of about 31 mm, cross directional bands of about 6 mm width can be spaced at about 44 mm intervals on the wrapping materials used to manufacture those cigarettes. Full flavor cigarettes are classified as those that yield about 14 mg or more of FTC “tar.” Ultra low tar cigarettes are classified as those that yield less than about 7 mg of FTC “tar.” Those cigarettes, have tobacco rods having appropriate wrapping materials possessing bands composed of appropriate amounts of appropriate components have the ability to meet the aforementioned cigarette extinction criteria. [0088]
Alternatively, with references to FIG. 3, wrapping [0089] material 25, may comprise ultrafine particles 80, distributed in selected regions, throughout the wrapping material. Wrapping material may also comprise ultrafine particles 80 substantially throughout the entire wrapping material to provide full coverage.
Wrapping [0090] material 25, may also comprise longitudinal bands 82 and 84 of ultrafine particles as shown in FIG. 4. Longitudinal bands may be about 1 to 15 mm wide and about 1 to 10 mm apart, preferably about 1 to 10 mm wide and 1 to 5 mm apart. Circumferential bands may be about 1 to 10 mm wide and spaced 1 to 50 mm apart, preferably about 1 to 10 mm wide and 1 to 20 mm apart. Each type of band may be applied with conventional paper making technologies such as those described herein above.
In an alternate embodiment, a glue utilized to seal the wrapping material may comprise ultrafine particles. This embodiment would look similar to the embodiment depicted in FIG. 4 with the glue comprising a longitudinal band wherein ultrafine particles are incorporated in the seam line of the tobacco articles. [0091]
With reference to FIGS. [0092] 1 to 4, the tobacco rod typically has a length which ranges from about 50 mm to about 85 mm, and a circumference of about 16 mm to about 28 mm. The tobacco rods and the resulting cigarettes can be manufactured in any known configuration using known cigarette making techniques and equipment. The wrapping material is formed into a circular shape such that the ends of the sides thereof abut one another. The ends of wrapping material can abut one another, nearly abut one another, or slightly overlap one another. A cigarette rod having such a configuration can be provided by supplying a paper wrapper from a bobbin on a suitably equipped cigarette making machine, passing the wrapping material through the garniture region of the cigarette making machine, and forming the tobacco rod. Equipment for providing a cigarette in such a manner is generally known to those of ordinary skill in the art and described in the patents referenced herein. Other equipment for manufacturing a cigarette in such a manner will be apparent to the skilled artisan.
Typically, the filter element has a length which ranges from about 20 mm to about 35 mm and a circumference of about 16 mm to about 28 mm. Typically, the filter element has a length which ranges from about 15 mm to about 40 mm, preferably about 20 mm to about 35; and a circumference of about 17 mm to about 27 mm, preferably about 22 mm to about 25 mm. The filter element can have a wide range of filtration efficiencies. [0093]
Cigarettes of the present invention can be manufactured from a variety of components, and can have a wide range of formats and configurations. Typical cigarettes of the present invention having cross directional bands applied to the wrapping materials of the tobacco rods of those cigarettes have static burn rates (i.e., burn rates of those cigarettes under non-puffing conditions) of about 50 to about 60 mg tobacco rod weight per minute, in the non-banded regions of those cigarettes. When coated with film treated materials incorporating ultrafine particles typical cigarettes of the present invention having cross directional bands applied to the wrapping materials of the tobacco rods of those cigarettes have static burn rates (i.e., burn rates of those cigarettes under non-puffing conditions) of less than about 50 mg tobacco rod weight per minute, generally about 40 to about 45 mg tobacco rod weight per minute, in the banded regions of those cigarettes. [0094]
The tobacco materials used for the manufacture of cigarettes of the present invention can vary. Descriptions of various types of tobaccos, growing practices, harvesting practices and curing practices are set for in [0095] Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999). The tobacco normally is used in cut filler form (e.g., shreds or strands of tobacco filler cut into widths of about {fraction (1/10)} inch to about {fraction (1/60)} inch, preferably about {fraction (1/20)} inch to about {fraction (1/35)} inch, and in lengths of about ¼ inch to about 3 inches). The amount of tobacco filler normally used within a cigarette ranges from about 0.6 g to about 1 g. The tobacco filler normally is employed so as to fill the tobacco rod at a packing density of about 100 mg/cm³to about 300 mg/cm³, and often about 150 mg/cm³to about 275 mg/cm³. Tobaccos can have a processed form, such as processed tobacco stems (e.g., cut-rolled or cut-puffed stems), volume expanded tobacco (e.g., puffed tobacco, such as propane expanded tobacco and dry ice expanded tobacco (DIET)), or reconstituted tobacco (e.g., reconstituted tobaccos manufactured using paper-making type or cast sheet type processes).
Typically, tobacco materials for cigarette manufacture are used in a so-called “blended” form. For example, certain popular tobacco blends, commonly referred to as “American blends,” comprise mixtures of flue-cured tobacco, burley tobacco and Oriental tobacco, and in many cases, certain processed tobaccos, such as reconstituted tobacco and processed tobacco stems. The precise amount of each type of tobacco within a tobacco blend used for the manufacture of a particular cigarette brand varies from brand to brand. See, for example, [0096] Tobacco Encyclopedia, Voges (Ed.) p.44-45 (1984), Browne, The Design of Cigarettes, 3^rdEd., p.43 (1990) and Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) p.346 (1999). Other representative tobacco blends also are set forth in U.S. Pat. No. 4,924,888 to Perfetti et al.; U.S. Pat. No. 5,056,537 to Brown et al.; and U.S. Pat. No. 5,220,930 to Gentry; and Bombick et al., Fund. Appl. Toxicol., 39, p. 11-17 (1997). See, also, PCT WO O2/37990.
If desired, in addition to the aforementioned tobacco materials, the tobacco blend of the present invention can further include other components. Other components include casing materials (e.g., sugars, glycerine, cocoa and licorice) and top dressing materials (e.g., flavoring materials, such as menthol). The selection of particular casing and top dressing components is dependent upon factors such as the sensory characteristics that are desired, and the selection of those components will be readily apparent to those skilled in the art of cigarette design and manufacture. See, Gutcho, [0097] Tobacco Flavoring Substances and Methods, Noyes Data Corp. (1972) and Leffingwell et al., Tobacco Flavoring for Smoking Products (1972).
Smoking articles also can incorporate at least one flavor component within the side seam adhesive applied to the wrapping material during the manufacture of the tobacco rods. That is, For example, various flavoring agents can be incorporated in a side seam adhesive CS-2201A available from National Starch, and applied to the seam line of the wrapping material. Those flavoring agents are employed in order to mask or ameliorate any off-taste or malodor provided to the smoke generated by smoking articles as a result of the use of the wrapping materials of the present invention. Exemplary flavors include methyl cyclopentenolone, vanillin, ethyl vanillin, 4-parahydroxyphenyl-2-butanone, gamma-undecalactone, 2-methoxy-4-vinylphenol, 2-methoxy-4-methylphenol, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, methyl salicylate, clary sage oil and sandalwood oil. Typically, such types of flavor components are employed in amounts of about 0.2 percent to about 6.0 percent, based on the total weight of the adhesive and flavor components. [0098]
Typically, the tipping material circumscribes the filter element and an adjacent region of the tobacco rod such that the tipping material extends about 3 mm to about 6 mm along the length of the tobacco rod. Typically, the tipping material is a conventional paper tipping material. The tipping material can have a porosity which can vary. For example, the tipping material can be essentially air impermeable, air permeable, or be treated (e.g., by mechanical or laser perforation techniques) so as to have a region of perforations, openings or vents thereby providing a means for providing air dilution to the cigarette. The total surface area of the perforations and the positioning of the perforations along the periphery of the cigarette can be varied in order to control the performance characteristics of the cigarette. [0099]
Embodiments of cigarettes of the present invention may exhibit a desirably high resistance to draw. For example, cigarettes of this invention exhibit a pressure drop of between about 50 and about 200 mm water pressure at 17.5 cc/sec. air flow. Typically, pressure drop values of cigarettes are measured using a Filtrona Filter Test Station (CTS Series) available from Filtrona Instruments and Automation Ltd. Cigarettes of this invention preferably exhibit resistance to draw values of about 70 to about 180, more preferably about 80 to about 150 mm water pressure at 17.5 cc/sec. air flow. [0100]
A cigarette of the present invention, when smoked, is capable of yielding an ash and firecone which are acceptable. The preferred ash is not overly dark in color and is not easily dislodged from the cigarette. The firecone is of acceptable length, is not overly cohesive, and is not overly fragile (i.e., the ash maintains its integrity). However, preferred cigarettes yield a fairly cohesive ash having a minimal amount of fractures and fissures, and yield a fairly continuous phase ash as provided by the wrapping material of the present invention. Preferred cigarettes yield an ash which exhibits a propensity to “fuse” to the ash of the tobacco column, and hence exhibit a tendency to be supported by the tobacco column ash. [0101]
In a further aspect, the present invention provides a method for modifying a performance attribute of a smoking article having a wrapper comprising wrapping material the method comprising distributing an ultrafine particles on a surface of the wrapping material. Preferably, the method further comprises distributing a plurality of ultrafine particles on the wrapping material. The ultrafine particles may be distributed in the manner described herein with reference to embodiments of smoking articles of the present invention. [0102]
The following examples are provided in order to further illustrate the invention but should not be construed as limiting the scope thereof. Unless otherwise noted, all parts and percentages are by weight. [0103]

EXAMPLES

Wrapping materials of the present invention were prepared using ultrafine particle sols and Trev. 454 woodpulp cigarette paper from Tervakoski having an inherent [0104] 38 CORESTA unit porosity, and 25 g/m²basis weight. The ultrafine particles sol was coated onto the Trev. 454 cigarette paper by placing the wire and/or felt sides of the paper in the sol to coat the paper and achieve full coverage at a desired grams of ultrafine particle per square meter of wrapping material (g ultrafine particle/m²wrapping material). The paper was then dried to remove the solvent. As a control, water was coated onto a sample of Trev. 454 cigarette paper using the same technique. For each example, sufficient Trev. 454 cigarette paper was coated to produce 8 cigarettes of the type shown in FIG. 1.
The cigarettes each had a length of about 84 mm and a circumference of about 24.8 mm, and include a tobacco rod having a length of 57 mm and a filter element having a length of about 27 mm. The tobacco rod included a smokable blend circumscribed by a layer of wrapping material. Each filter element comprised cellulose acetate tow plasticized with triacetin. Each filter element was attached to each tobacco rod using nonporous tipping paper. For each cigarette, the tipping paper circumscribes the filter element and about a 4 mm length of the tobacco rod in the region adjacent the filter element. The filter elements were ventilated to about 45 percent air dilution by providing a ring of mechanical perforations around the paper wrapping materials of the filter element about 13 mm from the extreme mouthend of the cigarette. [0105]
The smokable blend of the tobacco rod included tobacco material which had been cased with a casing mixture. The tobacco material had the form of a so-called “American blend,” and includes Flue-cured, Burley and Oriental tobaccos as well as reconstituted tobacco from a paper-making process, and volume expanded Flue-cured and Burley tobaccos. The blend of tobacco materials is cased using a mixture of glycerin, water and flavors. The blend was in the form of strands or shreds cut at about 25 cuts per inch (i.e., in cut filler form) and is equilibrated to a moisture level of about 12.5 percent. Each cigarette rod included about 650 mg tobacco material. [0106]
Eight cigarettes were used for each example. The cigarettes were employed by burning the tobacco rod such that the blend of smokable material within the paper wrapper burns to yield smoke. Cigarettes were then tested as described according to the aforementioned cigarette extinction procedure using the “vertical holder and horizontal substrate” configurations. [0107]

Comparative Example

As a control the cigarette wrapping material was coated with water incorporating no ultrafine particles. After drying, the resulting cigarette wrapping material had an inherent porosity of 42.4 CORESTA units. None of the cigarettes produced using the wrapping material extinguished during the test. [0108]

Example 1

The cigarette wrapping material was coated with an aqueous sol comprising SiO[0109] ₂ultrafine particles to achieve a full coverage coating of 0.74 g SiO₂/m²wrapping material. After drying, the resulting cigarette wrapping material had an inherent porosity of 35.2 CORESTA units. Four of the eight cigarettes produced using the wrapping material were self extinguishing on the substrate in the test.

Example 2

Cigarette wrapping material was coated with an aqueous sol comprising SiO[0110] ₂ultrafine particles to achieve a full coverage coating of 3.78 g SiO₂.m/²wrapping material. After drying the resulting cigarette wrapping material had an inherent porosity of 29.8 CORESTA units. All eight of the cigarettes produced using the wrapping material were self extinguishing in the test with 2 cigarettes self extinguishing in the holder and 6 cigarettes extinguishing on the substrate.
Although the present invention has been described with reference to particular embodiments, those of ordinary skill in the art will appreciate that the system of the present invention may be implemented in other ways and embodiments. Accordingly, the description herein should not be read as limiting the present invention as other embodiments also fall within the scope of the present invention. [0111]

Claims

What is claimed is:

1. A method for reducing the ignition propensity in a smoking article having a wrapping material comprising incorporating ultrafine particles in at least one region of the wrapping material.

2. The method of claim 1 wherein 1 the at least one region comprises substantially all of the wrapping material.

3. The method of claim 2 wherein the region is fully covered by ultrafine particles.

4. The method of claim 1 wherein the wrapping material comprises ultrafine particles in a plurality of regions.

5. The method of claim 1 wherein the ultrafine particles are distributed in a pattern.

6. The method of claim 5 wherein the pattern comprises a band and the wrapping material comprises a plurality of circumferential bands.

7. The method of claim 6 wherein each band has a width of at least about 0.5 mm to about 8 mm.

8. The method of claim 7 wherein spacing between the bands is at least about 10 mm to about 50 mm.

9. The method of claim 6 wherein the ratio of the length of the tobacco rod to the sum of the width of a band and the distance between the bands is in the range of 1 to 2.

10. The method of claim 5 wherein the pattern comprises a longitudinal strip.

11. The method of claim 10 wherein the longitudinal strip further comprises glue.

12. The method of claim 1 wherein the wrapping material exhibits an inherent porosity of less than about 30 CORESTA units.

13. The method of claim 1 wherein the ultrafine particles are applied to the wrapping material during production of the wrapping material.

14. The method of claim 11 wherein the ultrafine particles are applied in solution at a pH range of 2 to 12.

15. The method of claim 10 wherein the ultrafine particles are applied to the wire side of the wrapping material.

16. The method of claim 1 wherein the at least one region comprises 0.1 to 10 grams ultrafine particles per square meter of wrapping material in the region.