Patent Application
20070137668
The present invention relates to smoking articles, and in particular, to wrapping materials associated with those smoking articles. More specifically, the present invention relates to cigarettes, and in particular, to the positioning of additive material to desired locations of wrapping materials of cigarette rods.
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, surrounded by a paper wrapper, to form a “cigarette rod,” “smokable rod” or a “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 comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Certain cigarettes incorporate filter elements comprising, for example, activated charcoal particles. Typically, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.”
A cigarette is used by a smoker by lighting one end of that cigarette, and burning the tobacco rod. The smoker then receives mainstream smoke into his or her mouth by drawing on the opposite end of the cigarette. During the time that the cigarette is not being drawn upon by the smoker, the cigarette remains burning.
Numerous attempts have been made to control the manner that a cigarette burns when the cigarette is not being drawn upon. For example, cigarette papers have been treated with various materials to cause cigarettes incorporating those papers to self extinguish during periods when those cigarettes are lit but are not being actively puffed. Certain treatment methods have involved applying materials to the paper in circumferential bands or longitudinal stripes, creating areas that affect the burn rate of cigarettes incorporating that type of cigarette paper. See, for example, U.S. Pat. No. 3,030,963 to Cohn; U.S. Pat. No. 4,146,040 to Cohn; U.S. Pat. No. 4,489,738 to Simon; U.S. Pat. No. 4,480,650 to Weinert; U.S. Pat. No. 4,615,345 to Durocher; U.S. Pat. No. 6,606,999 to Crooks et al; U.S. Pat. No. 6,827,087 to Wanna et al; and U.S. Pat. No. 6,848,449 to Kitao et al.; and U.S. Patent Application Pub. Nos. 2003/0131860 to Ashcraft et al.; 2003/0150466 to Kitao et al.; 2004/0129281 to Hancock et al.; and 2004/0231685 to Patel et al., each of which is incorporated herein by reference. In addition, numerous references disclose applying films to the paper wrapping materials of tobacco rods. See, for example, U.S. Pat. No. 1,909,924 to Schweitzer; U.S. Pat. No. 4,607,647 to Dashley; and U.S. Pat. No. 5,060,675 to Milford et al., each of which is incorporated herein 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 suggesting various banded wrapping material configurations. See, for example, U.S. Pat. No. 1,996,002 to Seaman; U.S. Pat. No. 2,013,508 to Seaman; U.S. Pat. No. 4,452,259 to Norman 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.; U.S. Pat. No. 6,198,537 to Bokelman et al.; U.S. Pat. No. 6,779,530 to Kraker; U.S. Pat. No. 6,837,248 to Zawadzki et al; and U.S. Pat. No. 6,725,867 to Peterson et al.; and PCT Application Pub. No. WO U.S. Pat. No. 04/047572 to Ashcraft et al., each of which is incorporated herein by reference. Methods for manufacturing banded-type wrapping materials also have been disclosed. See, for example, U.S. Pat. No. 4,739,775 to Hampl, Jr. et al.; and U.S. Pat. No. 5,474,095 to Allen et al.; and PCT Application Pub. Nos. WO 02/44700 to Watkins and WO 02/055294 to Hammersmith et al. Some of those references describe banded papers having segments of paper, fibrous cellulosic material, or particulate material adhered to a paper web. See, U.S. Pat. No. 5,263,999 to Baldwin et al.; U.S. Pat. No. 5,417,228 to Baldwin et al.; U.S. Pat. No. 5,450,863 to Collins et al.; and U.S. Pat. No. 6,502,613 to Suzuki; and U.S. Patent Application Pub. No. 2005/0045297 to Garg et al. A representative method for manufacturing cigarettes having treated wrapping materials is set forth in U.S. Pat. No. 5,191,906 to Myracle, Jr. et al. Additive materials can be applied to cigarette paper wrapping materials while those wrapping materials are being used for cigarette manufacture (i.e., in a so-called “on-line” fashion). See, for example, U.S. Pat. No. 1,999,223 to Weinberger; U.S. Pat. No. 1,999,224 to Miles; and U.S. Pat. No. 6,848,449 to Kitao et al.; and U.S. Patent Application Pub. Nos. 2003/0150466 to Kitao et al.; 2004/0129281 to Hancock et al; 2004/0261805 to Wanna et al; and 2005/0039764 to Barnes et al.; and PCT Application Pub. No. WO 04/057986 to Hancock et al., each of which is incorporated herein by reference.
It would be desirable to apply additive material in a controlled manner as a predetermined pattern (e.g., as bands) to wrapping material of the type that is used for the manufacture of smokable rods for cigarettes. It also would be desirable to provide an additive material formulation that is capable of being applied to the wrapping material in an efficient and effective manner. It also would be desirable to ensure that the wrapping material so treated with additive material, when employed for the manufacture of a cigarette rod, yields a cigarette that meets standards of quality and behavior desired by the manufacturer of that cigarette.
The present invention provides manners and methods for manufacturing smoking articles, such as cigarettes. In a preferred aspect of the present invention, a suitable additive material is applied to a cigarette rod wrapping material. Preferred additive materials incorporate a pullulan component. The additive material is applied to at least one major surface of the wrapping material, and most preferably, to one major surface of the wrapping material.
The present invention also relates to wrapping materials having additive material formulations applied thereto (most preferably in a controlled manner), and to cigarettes manufactured from those wrapping materials. For example, the additive materials are applied to wrapping materials as a formulation of the present invention; and that formulation incorporates pullulan as a component. Representative formulations of additive materials are most preferably water-based formulations, but may alternatively be formulations containing water-miscible components (e.g., one or more alcohols) or non-aqueous formulations. Representative formulations can incorporate mixtures of pullulan with other film forming agents, such as, ethylcellulose, starches, and/or alginates. Other ingredients, such as flavoring agents, preservatives, pigments and/or colorants, also can be incorporated into those formulations. Other ingredients, such as water soluble and/or water insoluble filler materials (e.g., sodium chloride and/or calcium carbonate) may also be incorporated into those formulations.
Certain aspects of the present invention involve transferring additive material to, and retaining additive material on, desired locations of a wrapping material (e.g., paper wrapping web). For example, wrapping material having an adhesive-type formulation incorporating additive material disposed thereon may then be dried (e.g., to remove significant amounts of water from a water-based, pullulan-containing formulation) and wound onto a roll that is adapted for later use for smoking article manufacture.
Other aspects of the present invention involve transferring pullulan-containing additive material to, and retaining additive material on, desired locations of, a wrapping material suitable for use for smoking article manufacture (e.g., paper wrapping web) when manufacturing smoking articles from those materials using a cigarette making machine. That is, a formulation of additive material is applied to a continuous advancing strip of a paper web within a region of an automated cigarette making machine system (e.g., a machine designed to produce a continuous cigarette rod) in a desired amount, in a desired configuration and in a desired location.
For a wrapping material of the present invention, the region thereof coated with coating formulation of the present invention most preferably exhibits a diffusion capacity in that coated region, when measured at ambient temperature, that is relatively low; but exhibits a higher diffusion capacity in that coated region when measured after being subjected to exposure to a temperature significantly above ambient temperature. That is, the amount of pullulan, the relative amounts of pullulan and other additive material components, and the total amount of those components applied to the wrapping material (e.g., as a coated film) are such that the wrapping material exhibits the foregoing diffusion capacity-related behavior.
In another aspect of the invention, a smoking article incorporating a tobacco rod manufactured from wrapping material treated with the additive material formulation of the present invention can possess at least one band of additive material located in a region of its tobacco rod such that the band is capable of providing that smoking article with the ability to meet certain smoking article extinction criteria. Certain smoking articles of the present invention possessing tobacco rods manufactured using certain appropriately treated wrapping materials, 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, more preferably greater than about 90 percent, and most preferably about 100 percent, of cigarettes tested. Certain cigarettes of the present invention possessing tobacco rods manufactured using certain appropriately treated wrapping materials, when tested using the methodology set forth in the methodology set forth in ASTM Designation: E 2187-02b 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, more preferably greater than about 90 percent, and most preferably about 100 percent, of cigarettes tested.
The FIGURE is an exploded perspective of smoking article, showing the smokable material, the wrapping material components, and the filter element.
Referring to the FIGURE, there are shown the components of a smoking article 174 in the form of a cigarette. The cigarette 174 includes a generally cylindrical rod 186 of a charge or roll of smokable filler material 188 contained in a circumscribing wrapping material 190 of the present invention. The rod 186 is conventionally referred to as a “tobacco rod”. The ends of the tobacco rod are open to expose the smokable filler material. At one end of the tobacco rod 186 is the lighting end 195, and at the other end is shown a filter element 200. The cigarette 174 is shown as having one printed band 202 printed on wrapping material 190, and that band entirely circumscribes the cigarette rod in a direction transverse to the longitudinal axis of the cigarette. That is, the band provides a cross-directional region relative to the longitudinal axis of the cigarette. The band most preferably is applied to the inner surface of the wrapping material (i.e., facing the smokable filler material), but can be, in a much less preferred embodiment, on the outer surface of the wrapping material. Although the cigarette shown in The FIGURE possesses wrapping material having one band, the cigarette also can possess wrapping material having spaced bands numbering two, three, or more. The band 202 comprises additive materials of a water-based coating formulation incorporating at least one film-forming material. That coating formulation preferably incorporates pullulan material.
The cigarette 174 normally includes a filter element 200 or other suitable mouthpiece positioned adjacent one end of the tobacco rod 186 such that the filter element and tobacco rod are axially aligned in an end-to-end relationship, preferably abutting one another. Filter element 200 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 200 includes filter material 205 (e.g., plasticized cellulose acetate tow) that is overwrapped along the longitudinally extending surface thereof with circumscribing plug wrap material 206. The filter element 200 can have two or more filter segments, and/or flavor additives incorporated therein.
The filter element 200 is attached to the tobacco rod 186 by tipping material 208 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 208 is fixedly secured to the outer surface of the plug wrap 206 and the outer surface of the wrapping material 190 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 210, each of which extend through the tipping material and plug wrap.
Various representative types of cigarette components are set forth in U.S. Patent Application Pub. Nos. 2004/0255965 to Perfetti et al.; 2004/0261807 to Dube et al.; 2005/0066982 to Clark et al. and 2005/0066986 to Nestor et al., which are incorporated herein by reference. In addition, if desired, at least one of the various adhesives (e.g., water-based adhesive formulations) used for the manufacture of the cigarette (e.g., the adhesive formulation used for providing the seam line of the tobacco rod, the adhesive formulation used for providing the seam line of the plug wrap, and/or the adhesive used in association with the tipping paper) can incorporate pullulan material as an ingredient.
Various types of equipment and methods for manufacturing cigarettes, and for applying additive material formulation to smoking article wrapping material, are known. For example, representative types of equipment and the operation thereof are set forth in U.S. Pat. No. 6,848,449 to Kitao et al.; U.S. Patent Application Pub. Nos. 2003/0150466 to Kitao et al.; 2004/0129281 to Hancock et al.; 2004/0231685 to Patel et al; and 2005/0039764 to Barnes et al.; and PCT Application Pub. No. WO 04/057986 to Hancock et al., which are incorporated herein by reference. Other representative techniques for applying additive material formulation to wrapping material are set forth in U.S. Pat. No. 6,779,530 to Kraker; U.S. Patent Application Pub. Nos. 2005/0103355 to Holmes and 2005/0194014 to Read, Jr.; and PCT Application Pub. Nos. WO 04/047572 to Ashcraft et al. and WO 04/095957 to Bray et al., which are incorporated herein by reference. As such, there are various known manners and methods for applying additive material formulations in a desired manner (e.g., as a coating or film) to desired locations and/or in desired patterns on wrapping materials, such as paper wrapping materials suitable for use for the manufacture of tobacco rods for cigarettes.
Coating formulation incorporating the additive material typically is applied to wrapping material that is supplied from a roll. In one regard, the formulation can be applied to wrapping material supplied from a bobbin. The amount of wrapping material on a bobbin can vary, but the length of continuous strip of wrapping material on a bobbin typically is more than about 6,000 meters; and generally, the length of continuous strip of wrapping material on a bobbin typically is less than about 7,000 meters. The width of the wrapping material can vary, depending upon factors such as the circumference of the smokable rod that is manufactured and the width of the overlap region zone that provides for the sideseam. Typically, the width of a representative continuous strip of wrapping material useful for cigarette rod manufacture is about 24 mm to about 30 mm.
Paper 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. Most preferably, the wrapping material possesses the coated 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. That is, when the wrapping material is used to manufacture a smokable rod, the “wire side” major surface of the wrapping material that circumscribes the smokable material faces that smokable material. Typically, the “felt” side of the wrapping material is used as the visible outer surface of the tobacco rod. 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 and cigarette manufacture.
The selection of a particular wrapping material will be readily apparent to those skilled in the art of cigarette design and manufacture. Typical paper wrapping materials are manufactured from fibrous materials (e.g., a cellulosic materials, such as wood pulp), and optional filler materials (e.g., calcium carbonate), to form so-called “base sheets.” Such wrapping material base sheets have basis weights that can vary, and exhibit porosities that can vary. See, for example, the representative wrapping materials, including those commercially available paper wrapping materials that are set forth in U.S. Pat. Application Pub. No. 2004/0129281 to Hancock et al.; PCT Application Pub. Nos. WO 04/047572 to Ashcraft et al.; and WO 04/057986 to Hancock et al. Other wrapping materials, and components thereof, are set forth in U.S. Pat. No. 6,868,855 to Shafer et al. and U.S. Pat. Application Pub. No. 2004/0134631 to Crooks et al.; and EP 1234514 to Grider et al.; which are incorporated herein by reference.
The base sheets 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 compositions thereof. For example, a base sheet can be electrostatically perforated, coated with a film, treated with burn chemicals, or treated with flavoring agents or aroma precursors. Various additives can be added to, or otherwise incorporated into, the wrapping material simultaneously to, or at different stages during or after, the paper manufacturing process. See, for example, U.S. Pat. Application Pub. No. 2004/0129281 to Hancock et al.; PCT Application Pub. Nos. WO 04/047572 to Ashcraft et al.; and WO 04/057986 to Hancock et al., which are incorporated herein by reference.
The coating formulation that is applied to the wrapping material includes at least one film-forming agent. A preferred film-forming agent is pullulan. Pullulan is a polysaccharide polymer that may be produced through the reaction of Aureobasidium Pullulan yeast on starch. Exemplary forms of pullulan have been designated CAS No. 9057-02-7; and representative forms of pullulan are available commercially as PI-20 and PF-20 from Hayashibara Biochemical Laboratories, Inc.; P1830 from Spectrum Chemical Mfg. Corp., SLP-2119 from ScienceLab.com, Inc.; P4516 from Sigma-Aldrich, Inc.; and BioChemika Ultra 70051, 70074, 82440, 82441, 82442, 82445, 82446, 82550 and 91335 through Sigma-Aldrich Co. See, for example, Leathers, BioPolymers Online: Biology, Chemistry, Biotechnology, Applications Part 6. Polysaccharides Pullulan (Jan. 15, 2005); and The EFSA Journal (2004) 85, 1-32, which are incorporated herein by reference. See, also, U.S. Pat. No. 4,650,666 to Izutsu et al.; U.S. Pat. No. 5,015,480 to Childers et al.; U.S. Pat. No. 5,518,902 to Ozaki et al.; U.S. Pat. No. 6,887,307 to Scott et al. and U.S. Pat. No. 6,923,981 to Leung et al., and U.S. Pat. Application Pub. No. 2005/0249676 to Scott et al., which are incorporated herein by reference.
One embodiment of a pullulan-containing coating formulation may be cast as a sheet and dried. That pre-formed sheet can then be subdivided into pieces or strips of desired size, and applied to the wrapping material. Pieces or strips of a cast pullulan-containing sheet materials can be positioned at desired locations on one or both major surfaces of the paper wrapping material, and adhered thereto using moisture, heat and/or application of pressure.
Another embodiment of a pullulan-containing coating formulation can be provided in the form of fibers, preferably formed as a non-woven sheet, and applied to the paper wrapping material. A formulation incorporating a film-forming agent, such as a pullulan-containing coating formulation, can be melt-blown or otherwise processed in order to provide a loose fabric or web such as a non-woven web comprised of a plurality of fibers. For example, pullulan, plasticizer, and an optional solvent can be heated in order to provide a melted mixture, and the resulting melted mixture can be provided in a fibrous form using a spinneret, or other suitable means. The resulting fibers may then be formed into a non-woven web. That non-woven web then can be subdivided into pieces or strips of desired size, and applied to the paper wrapper material by, for example, thermal application or an adhesive means. Pieces or strips of pullulan-containing sheet materials can be positioned at desired locations on one or both major surfaces of the paper wrapping material, and adhered thereto using moisture, heat and/or application of pressure. Preferably, the fibers in the loose fabric or web are distributed such that they are fused together in a sufficient plurality of locations to provide for patency of the fabric/web structure and are spaced sufficiently apart to allow airflow between the fibers. Characteristics of various exemplary types of non-woven webs, particularly those of the type useful for the manufacture of cigarette filter components, are set forth in U.S. Pat. No. Re 35,206 to Hassenboehler, Jr. et al.; U.S. Pat. No. 4,903,714 to Barnes et al.; and U.S. Pat. No. 5,246,017 to Saintsing et al.; which are incorporated herein by reference.”
In some embodiments, virtually all of the film-forming agent within the formulation can be comprised of pullulan. However, in other embodiments, in addition to pullulan, other film-forming agents can be incorporated within the coating formulation. Another film forming agent can be an alginate, such as sodium alginate, potassium alginate, ammonium alginate, and the like. Exemplary alginates are available as Kelgin RL, Manucol LD, Manucol LB, Manugel LBA, and Keltone LVCR NF from ISP Corporation. Another film-forming agent can be hydroxypropylcellulose. An exemplary hydroxypropylcellulose is available as Klucel EF from Hercules, Inc. Other exemplary film-forming agents include starch-based materials, ethylcellulose, carrageenans, polyvinylacetate, polyvinylalcohol, chitosan, or combinations thereof, and the like. See, for example, the types of film-forming agents set forth in U.S. Pat. No. 6,779,530 to Kraker; U.S. Pat. Application Pub. No. 2005/0076929 to Fitzgerald et al.; U.S. patent application Ser. No. 11/109,404 to Oglesby et al., filed Apr. 19, 2005, to Oglesby et al.; and U.S. patent application Ser. No. 11/215,632, filed Oct. 14, 2005, to Oglesby; which are incorporated herein by reference. See, also, U.S. Pat. Application Pub. No. 2003/0086954 to O'Halloran et al., which is incorporated herein by reference.
For representative coating formulations, there can be varying amounts of each of the pullulan and other optional film-forming agent relative to one another. Preferably, the pullulan is employed in amounts sufficient to provide a film or coating on the wrapping material, and to provide a coated region having a relatively low porosity. In addition, the pullulan may be employed such that the coating formulation has the form of a paste that can be readily applied in a desired fashion to the wrapping material. It is preferred that rheology of the coating formulation is not overly thick or overly thin, but that the paste can be applied to a wrapping material without damaging the material. Another film-forming agent may be employed in amounts sufficient to ensure that the coated region of the wrapping material exhibits a desirably low porosity. In addition, the other film-forming agent may be employed in amounts sufficient to ensure that the rheology of the coating formulation is acceptable, and that the coating formulation can readily be applied in a desired fashion to the wrapping material.
The weight of pullulan with the coating formulation relative to the other optional film-forming agents can vary. For example, the amount of pullulan within the coating formulation can make up at about 10 percent to about 90 percent, often about 20 percent to about 80 percent, of the combined weight of pullulan and alginate film-forming agents within the formulation. In certain preferred embodiments, the weight of pullulan within the coating formulation is greater than the weight of the other optional film-forming agents within the formulation. In these embodiments, the amount of pullulan within the coating formulation often makes up at least about 50 percent, often about 65 percent, and frequently at least about 75 percent, of the combined weight of the pullulan and other film-forming agent ingredients within the formulation. When present, the amount of other film-forming agent within the coating formulation often makes up at least about 5 percent, and frequently at least about 10 percent, of the combined weight of the pullulan and other film-forming agent within the formulation. In certain preferred embodiments, the amount of other film-forming agent less than about 50 percent, often less than about 35 percent, frequently less than 25 percent, of the combined weight of the pullulan and other film-forming agent within the formulation.
The coating formulation can incorporate other ingredients, in addition to the aforementioned film-forming materials. See, for example, the types of ingredients, and amounts of those ingredients, set forth in U.S. Pat. Application Pub. No. 2004/0129281 to Hancock et al.; PCT Application Pub. No. WO 04/057986 to Hancock et al.; and U.S. patent application Ser. No. 11/251,632, filed Oct. 14, 2005, to Oglesby. In addition, see those types and amounts of ingredients incorporated into the pullulan-containing formulations set forth in U.S. Pat. No. 6,923,981 to Leung et al. and U.S. Pat. Application Pub. No. 2003/0086954 to O'Halloran et al., which are incorporated by reference herein. Those other ingredients can be dissolved within the liquid carrier of the coating formulation, or dispersed or suspended within that coating formulation. Those other ingredients can be employed in order to provide specific properties or characteristics to the wrapping material. For example, the coating formulation can incorporate flavoring agents, humectants, sugars (e.g., sucrose, glucose, fructose, maltose, melezitose, lactose, galactose and mannose), syrups (e.g., high fructose corn syrup and honey), wetting agents, preservatives, colorants or pigments, and the like. Though not preferred, the coating formulation can incorporate water soluble (e.g., sodium chloride or potassium chloride) and/or water insoluble (e.g., calcium carbonate or magnesium oxide) fillers. Preferably, the optional ingredients are essentially chemically non-reactive with other components of the formulation, at least at those conditions at which the formulation is employed. Preferably, the optional ingredients are employed in amounts that do not result in introduction of undesirable rheology to the coating formulation (e.g., introducing an undesirably high viscosity to the formulation).
The suitable solvent or liquid carrier of the coating formulation most preferably is a liquid having an aqueous character, and can include relatively pure water (e.g., tap water or de-ionized water). Although not all components of the coating formulation are necessarily soluble in the liquid carrier, it is most preferable that the film-forming components be soluble (or at least highly dispersible) in that liquid. By “soluble” in referring to the components of the coating formulation with respect to the liquid solvent, it is meant that the components for a thermodynamically stable mixture when combined with the solvent, have a significant ability to dissolve in that solvent, and do not form precipitates to any significant degree when present in that solvent.
The pullulan preferably is incorporated within a suitable solvent, such as an aqueous liquid, to produce a coating formulation that is considered to be a thickened mixture. Preferred coating formulations can be considered to be a “paste.” A representative water-based coating formulation having a pullulan content of about 21 weight percent to about 25 weight percent exhibits a Brookfield viscosity (No. 6 spindle, 10 rpm, 25° C.) of about 6,000 to about 12,000 centipoise. For example, a representative water-based coating formulation having a pullulan content of about 23 weight percent exhibits a Brookfield viscosity (No. 6 spindle, 10 rpm, 25° C.) of about 8,000 centipoise. A representative water-based coating formulation having a pullulan content of about 30 weight percent to about 38 weight percent exhibits a Brookfield viscosity (No. 6 spindle, 5 rpm, 25° C.) of about 100,000 to about 300,000 centipoise. For example, a representative water-based coating formulation having a pullulan content of about 34 weight percent exhibits a Brookfield viscosity (No. 6 spindle, 5 rpm, 25° C.) of about 180,000 centipoise. Preferred coating formulations also can be considered to be adhesives, as it is desirable for those coatings to remain in intimate contact with (e.g., to adhere to or otherwise remain secured to) desired locations on the wrapping material to which those formulations are applied.
Coating formulations may incorporate about 50 to about 90, generally about 60 to about 85, weight percent liquid carrier (e.g., an aqueous solution such as relatively pure water, or a non-aqueous solution); about 10 to about 45, generally about 15 to about 50, weight percent of the film-forming agent mixture (e.g., the combined weight of the pullulan and other optional film-forming components); based on the total weight of liquid carrier and film-forming agent mixture.
The relative amounts of the various other optional components of the coating formulation can vary. In many preferred embodiments, the combined amounts of ingredients such as flavorings, colorants, preservatives, fillers, and the like, typically do not exceed about 5.0 percent, often do not exceed 40 percent, and frequently do not exceed about 30 percent, of the total combined weight of the film-forming agent components and optional components.
Coating formulations, such as the types of water-based coating formulations described hereinbefore, are subjected to drying conditions after those formulations have been applied to the wrapping material, such as a continuous strip of paper web of wrapping material. Preferably, sufficient solvent is removed from the formulation after that formulation has been applied to the wrapping material such that the additive material that remains in contact with the wrapping material does not exhibit a sticky or tacky character or nature. Preferably, sufficient solvent (e.g., water or a non-aqueous solvent) is removed from the formulation after that formulation has been applied to the wrapping material such that the additive material that remains in contact with the wrapping material exhibits a solvent (e.g., moisture) content of less than about 10 percent, more preferably less than about 8 percent, based on the weight of the coating formulation that remains in contact with the wrapping material. Preferably, sufficient solvent (e.g., water or a non-aqueous solvent) is removed from the formulation after that formulation has been applied to the wrapping material such that the formulation that remains in contact with the wrapping material exhibits a solvent (e.g., moisture) content of about 4 percent to about 6 percent, based on the weight of the coating formulation that remains in contact with the wrapping material.
The amount of coating formulation that is applied to the wrapping material can vary. The coating formulation may be applied to the wrapping material such that the dry weight of the additive material on the wrapping material is least about 1 g/m2, often at least about 2 g/m2, and frequently at least about 3 g/m2. The coating formulation may be applied to the wrapping material such that the dry weight of the additive material on the wrapping material is less than about 10 g/m2, often is less than about 7 g/m2, and frequently is less than about 4 g/m2. For example, a paper wrapping material having a dry basis weight of about 25 g/m2 can be coated with coating formulation and dried to have a resulting overall dry basis weight in the coated regions of about 27 g/m2 to about 28.5 g/m2.
Coated regions of the wrapping material useful as the circumscribing wrapper of tobacco rods for cigarettes are produced using additive materials that are effective in reducing the porosity of the wrapping material in those regions. Film-forming materials coated onto the wrapping material have a tendency to reduce the porosity of the wrapping material. Typical coated regions of the wrapping materials have porosities that can vary. Preferably, the porosities of the coated regions of the wrapping materials are less than about 9 CORESTA units, and usually are less than about 8 CORESTA units. Typically, the porosities of the coated regions of the wrapping materials are at least about 0.1 CORESTA unit, usually are at least about 1 CORESTA unit, often are at least about 3 CORESTA units. Preferably, the porosities of the coated regions of the wrapping materials, particularly those wrapping materials that are used for the manufacture of cigarettes designed to meet certain cigarette extinction test criteria, are from about 3 CORESTA units to about 6 CORESTA units.
The wrapping material can possess patterns of predetermined shapes and sizes positioned at predetermined locations, and hence, cigarettes appropriately manufactured from that wrapping material can possess coated patterns of predetermined shapes and sizes positioned at predetermined locations on their smokable rods. Representative patterns are set forth in U.S. Pat. Application Pub. No. 2004/0129281 and PCT Application Pub. No. WO 04/057986, both to Hancock et al. For example, shapes of coated regions, compositions of the coating formulations, or amounts or concentrations of coating materials, 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. Cross-directional lines or bands that are essentially perpendicular to the longitudinal axis of the wrapping material often extend sufficiently across the wrapping material such that smokable rods manufactured from that wrapping material extend virtually completely around those smokable rods. Cigarettes also 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 include 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.
Preferred wrapping materials possess coatings 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 spacing between those bands. Typically, those bands have widths of at least about 2 mm, usually at least about 3 mm, frequently at least about 4 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, and often have widths of about 6 mm to about 7 mm. Such bands can be spaced apart such that the spacing between the bands (i.e., as measured from the inside adjacent edges of 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. For certain preferred wrapping materials, the bands are spaced apart such that the spacing between the bands is about 15 mm to about 25 mm, more preferably about 18 mm to about 24 mm.
Preferably, the coating formulation has an overall composition, and is applied in a manner and in an amount, such that the physical integrity of the wrapping material is not adversely affected when the coating formulation is applied to selected regions of the wrapping material. It is desirable that the components of the coating formulation 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. Specifically, it desirable that components of the coating formulation not introduce undesirable sensory characteristics to the smoke generated by a smoke article incorporating a wrapping material treated with that coating formulation. For preferred cigarettes, it is desirable that the coating formulation applied to the wrapping material provide the desirable extinction performance characteristics to the cigarettes manufactured using that wrapping material at relatively low coating or application levels.
Diffusion, with regards to a cigarette wrapping material having a coated region of additive material, is the amount of gas transported through the wrapping material when a gas concentration gradient is present. See, Baker et al., The Diffusion of Carbon Monoxide out of Cigarettes, Beitr. Tabaorsch., Vol. 9(3), 131-140 (1977); Drake et al., On a Cell to Measure Diffusion Coefficients of Gases through Cigarette Papers, Int. J. Heat Mass Transfer, Vol. 23, 127-134 (1980); Baker, The Viscous and Inertial Flow of Air through Perforated Papers, Beitr. Tabakforsch., Vol. 14(5), 253-260 (1989); Miura, Oxygen Diffusion through Cigarette Paper, Beitr. Tabakforsch., Vol. 19(4), 205-208 (2001); Miura et al., Heat Emission from a Burning Cigarette, Beitr. Tabakforsch., Vol. 19(5), 245-249 (2001); Rostami et al., Modeling the Diffusion of Carbon Monoxide and Other Gases from the Paper Wrapper of a Cigarette During Puffing, J. Anal. Pyrolysis, Vol. 66, 263-280 (2003); Rostami et al., Modeling of a Smoldering Cigarette, J. Anal. Pyrolysis, Vol. 66, 281-301 (2003). An apparatus suitable for measuring the diffusion capacity of a wrapping material, including coated regions thereof, is set forth in U.S. Patent Application Pub. No. 2005/0087202 to Norman et al., which is incorporated herein by reference. See, also, Norman et al., Measurement of Gas Diffusion Capacity of Cigarette Papers (2005), which is incorporated herein by reference.
A preferred wrapping material possesses a coated region exhibiting a diffusion capacity in that coated region (when measured at ambient temperature) that is relatively low, but exhibits a diffusion capacity in the coated region (when measured after being subjected to exposure to a temperature significantly above ambient temperature) that is relatively high. For example, ratios of diffusion capacities for an uncoated region to a coated region of a wrapping material embodiment of the present invention (e.g., for a wrapping material heated at about 230° C. for an effective period of time and cooled to ambient for measurement, relative to a wrapping material maintained and measured at ambient temperature) can be greater than 1.5:1. See, U.S. Patent Application Pub. No. 2005/0087202 to Norman et al. See, also, Norman et al., Measurement of Gas Diffusion Capacity of Cigarette Papers (2005).
A preferred embodiment of a wrapping material includes one or more bands of a coating formulation of the present invention. After heating substantially above ambient temperature, and preferably at about 230° C. for about 15 minutes, the portion(s) of the wrapping material with the band(s) of the coating formulation preferably has a diffusion capacity of at least about 0.9 cm/sec. In preferred embodiments of the wrapping material, the coating formulation is applied at a coating weight of about 1.5 g/m2 to about 3 g/m2.
A preferred cigarette incorporating a tobacco rod manufactured from wrapping material treated with the additive material formulation of the present invention meets extinction criteria while also exhibiting a propensity to avoid self-extinction during normal smoking conditions. That is, a preferred cigarette, while being capable of meeting the certain extinction criteria, does not experience free air self-extinction to a significant degree, and most preferably there is a low rate of occurrence free air self-extinction. For example, a preferred cigarette does not have a tendency to undergo premature extinction, such as when lit cigarettes are held in the smoker's hand or when placed in an ashtray for a brief period of time. Preferred cigarettes undergo free air self-extinction for less than about 30 percent, preferably for less than about 15 percent, and most preferably for 0 percent, of cigarettes tested. Free air self-extinction with regards to a cigarette having a tobacco rod incorporating a wrapping material possessing circumscribing bands of additive material relates to those burning cigarette rods that extinguish when left to burn in air (and not in contact with a substrate).
The following examples are provided in order to further illustrate the present invention, but should not be construed as limiting the scope thereof. Unless otherwise noted, all parts and percentages are by weight.
Strips from commercially available Listerine™ Cool Mint PocketPaks™ from Pfizer, Inc., (see U.S. Pat. App. Pub. No. 2005/0031675, incorporated herein by reference) which incorporate pullulan as an ingredient, are evaluated for ignition temperature, which is determined to be about 430° C. to about 455° C. Other Listerine™ Cool Mint PocketPaks™ are taken from their package, and are cut into generally rectangular patches or strips having dimensions of about 6 mm by about 24 mm. Each strip is lightly moistened with water, and is attached to the cigarette paper of the tobacco rod of a cigarette of the type commercially available as Camel Light from R. J. Reynolds Tobacco Company. Each strip is located at about the midway point of each tobacco rod. Each strip is positioned on the outer face of the cigarette paper so as to form a band that completely circumscribes the tobacco rod. As such, each strip is attached to the outer face of the cigarette paper as a band that extends around the cigarette perpendicularly to the longitudinal axis of the cigarette.
Each cigarette is evaluated for self-extinction properties using the type to test method set forth in ASTM Designation: E 2187-02b using 10 layers of Whatman No. 2 filter paper. Extinction criteria are met for 100 percent of the cigarettes tested.
Commercially available Listerine™ Cool Mint PocketPaks™ from Pfizer, Inc., which incorporate pullulan as an ingredient, are mixed with water such that about 5 g thereof are dissolved in about 20 g of water. The resulting mixture possesses a solids content of about 17 percent, and a viscosity of about 3000 to 5000 centipoise Brookfield viscosity, 10 rpm, #6 spindle, at 25° C. Droplets of that mixture are placed just outside the edge of a strip of cigarette paper/web available as Ref. No. TK509 (46 CORESTA units) from Tervakoski. The cigarette paper is fixed on a glass plate, and droplets of the liquid mixture are drawn across the strip of paper using a #10 Meyer rod. The coated paper then is dried at room temperature for about 24 hours. As such, the strip of cigarette paper/web possesses a series of spaced bands that extend across the width of the paper, generally perpendicular to the longitudinal axis of the paper strip. The resulting paper is evaluated by testing diffusion coefficients both at ambient temperature and at 230° C.
Diffusion capacities of the wrapping materials in the regions of the bands provided by the coating formulation are determined using the apparatus and methodologies set forth in U.S. Patent Application Pub. No. 2005/0087202 to Norman et al. See, also, Norman et al., Measurement of Gas Diffusion Capacity of Cigarette Papers (2005).
The resulting web having spaced bands applied thereto possesses bands having average diffusion capacities, measured at 25° C., of about 0.09 cm/sec.
Diffusion capacities of the wrapping materials in the regions of the bands provided by the coating formulation are determined at 25° C. after heating the band region of wrapping material substantially above ambient temperature in, for example, a radiant oven at about 230° C. for about 15 minutes, and then cooling the band region to about 25° C. The resulting web having spaced bands applied thereto possesses bands having average diffusion capacities of about 0.16 cm/sec.
The liquid mixture described in Example 2 is applied to the cigarette paper of the tobacco rod of a cigarette of the type commercially available as Camel Light from R. J. Reynolds Tobacco Company. The mixture is applied as a circumscribing band located at about the midway point of each tobacco rod. The cigarettes are lit, and they self extinguish at the banded area when laid on a stack of 10 layers of filter paper.
A water-based additive formulation incorporating pullulan is provided as follows, and is applied as a pattern to a cigarette paper wrapper in the following manner.
Tap water is heated to, and maintained at, about 60° C. Potassium sorbate is added to the water in a manner such that the potassium sorbate dissolves in the water. Colorant in the form of a water-based dye also is added. Then, pullulan (available as PI-20 from Hayashibara Biochemical Laboratories, Inc.) is added to the water in a manner such that it is dispersed within the water. An aqueous mixture of the pullulan as a 10 percent solution at 30° C. is expected to exhibit a viscosity of about 100 to about 189 centistokes. During addition of the various components to the water, the water is rapidly stirred using an electric mixer. The resulting mixture has a relatively uniform consistency. The resulting mixture is comprised of about 77 parts water, about 22.6 parts pullulan, about 0.2 parts colorant, and about 0.2 parts potassium sorbate.
The resulting aqueous mixture is cooled to room temperature. The mixture at room temperature has a relatively uniform consistency and resembles a paste. After being allowed to sit for about 24 hours at ambient temperature, the mixture exhibits a Brookfield viscosity (No. 6 spindle, 10 rpm, 25° C.) of about 8,000 centipoise.
An application apparatus of the type generally as described with reference to
The application apparatus is operated so as to feed web of wrapping material from the bobbin through the applicator system at a rate of 300 meters per minute. As such, the coating formulation is applied to the web while the coating formulation is maintained at a temperature slightly above ambient. The coated web is dried and collected.
Paper of the type set forth in Example 4 is coated using equipment of the general type set forth in Example 4. However, the roller that is employed possesses a groove depth of about 1.0 mi, and the formulation is applied to the paper web running at a speed of about 100 meters per minute. In addition, the coating formulation that is employed includes about 58.825 parts water, about 16.875 parts of the pullulan that is described in Example 4, about 25 parts sodium chloride, about 0.15 parts potassium sorbate, and about 0.15 parts colorant. The paper so coated can be collected, and the dry weight coating is applied in an amount of about 2.0 to about 4.0 g/m2.
Paper of the type set forth in Example 4 is coated using equipment of the general type set forth in Example 4. However, the roller that is employed possesses a groove depth of about 1.0 mil, and the formulation is applied to the paper web running at a speed of about 100 meters per minute. In addition, the coating formulation that is employed includes about 77.1 parts water, about 11.25 parts of the pullulan that is described in Example 4, about 11.25 parts alginate available as Manucol LB from ISP Corporation, about 0.2 parts potassium sorbate, and about 0.2 parts colorant. The paper so coated can be collected, and the dry weight coating is applied in an amount of about 2.0 to about 4.0 g/m2.
It is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
