MXPA98001919A - Wrapping of an article to smoke to control the proclivity or propension to the ignition of an article to smoke without affecting the characteristics of fu - Google Patents

Abstract

The present invention relates to a wrapper of the smoking article having discrete areas of reduced permeability to improve the characteristics of proclivity or propensity to ignite a smoking article. The areas of reduced permeability define a permeability profile gradually decreased in a direction of burning of the smoking article so that the reduction of permeability in the areas of reduced permeability increase from a minimum reduction to a reduction of maximum permeability in the direction of burning of the article for fum

Description

WRAPPING OF A SMOKING-INSULATING PROCLIVITY OR PROPENSION TO THE IGNITION OF AN ARTICLE TO SMOKE WITHOUT AFFECTING SMOKING CHARACTERISTICS.

FIELD OF THE INVENTION The present invention relates to a wrap composition of the smoking article, and to a method of preparing the wrap composition of the smoking article, to significantly reduce the proclivity or propensity of ignition of the smoking article without adversely affecting smoking characteristics. or the action of smoking. The invention particularly relates to an improved wrapping paper for cigarettes wherein the bands treated on the cigarette wrap tend to cause the cigarette to self-extinguish if they are set aside or dropped onto a substrate before the ignition of the substrate. .

REF: 27056 BACKGROUND OF THE INVENTION There is an industry-referenced activity for producing cigarettes having wraps that reduce the ignition proclivity of the smoking article, or the tendency of the smoking article to ignite surfaces that come into contact with the smoking article. There have been reports of fires attributed to the burning of cigarettes that come in contact with combustible materials. A justifiable interest exists in the industry to reduce the tendency of cigarettes, or other articles to smoke, that burn surfaces and materials used in accessories or furniture, bedding, and similarly during contact. Therefore, a desirable feature of smoking articles, particularly cigarettes, is that they are self-extinguishing when dropped or set aside in a state of free combustion on combustible materials. It has been recognized in the long term in the industry that cigarette wrapping has a significant influence on the characteristics of smoldering or smoldering of the cigarette. In this regard, several attempts have been made in the technique to alter or modify the cigarette wrappings to achieve the desired tendency of the cigarette to self-extinguish or self-extinguish, or in other words to reduce the characteristics of proclivity or propensity to ignite cigarettes. Prior references describe the application of fibrous waxy pastes and / or film-forming solutions to cigarette paper to reduce permeability and control the rate of burning. It has been shown that when these materials have been applied in discrete bands around the circumference of the cigarette, the cigarette shows a reduced propensity of the cigarette to ignite a substrate and has an increased puff count. For example, it is known from US Patent No. 4,452,259 to define at least one circumferential band on the wrapping of a smoking article which will hopefully cause the article to smoke to be extinguished or quenched under free-burning conditions. The band is formed by applying a liquid or composite substance to the cigarette paper which has a liquid form at a temperature ranging from about 100 ° C to 200 ° C. This reference teaches that, when the cone burns of the cigarette It comes into contact with the band, the compound forms a liquid film on the cigarette paper that substantially restricts the flow of air to the burning coal. U.S. Patent No. 4,945,932 teaches another method for providing areas of decreased air permeability, which cause the cigarette to self-extinguish or self-extinguish such as smoldering or burning of the cigarette in the area of reduced permeability. The '932 patent teaches forming shaped or annular zones in the paper of the cigarette in the form of sticks: multiple of the paper, for example, by the use of a calendar of embossing. U.S. Patent No. 4,077,414 discloses the use of printed webs of material on cigarette paper to control the burning rate of the cigarette. Although this reference is not particularly directed to the ignition proclivity, teaches to provide relatively narrow porosity bands, throughout the cigarette. The bands are formed by applying a gel-forming substance to the paper by painting, printing, or other coating techniques. The reference teaches that preferred gel-forming substances are. those that form gels in water, such as gelatin, alginates, methyl cellulose, methylethyl cellulose and gums. Water insoluble substances such as lacquers and varnishes can also be used in an organic solvent. U.S. Patent No. 4,889,145 is another reference teaching to provide areas of reduced porosity throughout the cigarette by applying a discontinuous coating of a porosity reducing composition. This reference is not particularly related to the ignition proclivity of the smoking or smoking article, but rather to the control of the puff count or puff and tar released from the smoking article. This reference also teaches to include a combustion or combustion promoter in the envelope to balance the effect of the discontinuous coating areas. Several other applications and processes for reducing the ignition proclivity of a cigarette are known as, for example, from U.S. Patent No. 4,453,553; U.S. Patent No. 4,480,650; U.S. Patent No. 4,739,775; U.S. Patent No. 4,489,738; U.S. Patent No. 4,715,345; U.S. Patent No. 2,666,437; U.S. Patent No. 4,622,983; and European Patent Application 0 559 300 82.

Although, as described in the references cited above, various methods and processes for applying discrete bands of porosity reducing material to cigarette papers are known, such conventional techniques have a significant disadvantage in that a marked change in the smoking characteristics of the cigarette can be detected when.-the mineral coal of the cigarette is burned in the treated bands. This is particularly noticeable if a puff has descended when the combustion coal reaches the division between a treated and untreated portion of the paper. A perceptible difference in flavor and smoke release is distinguished by the - smoker depending on the difference in permeabilities between the treated and untreated sections of the paper. Therefore, what is needed is a paper which - remains effective in reducing the propensity or proclivity to ignition while minimizing the possibility of discernible changes in the release of smoke and flavor for a smoker.

OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION It is a principal object of the present invention to provide a smoking or smoking article, particularly a cigarette, having improved proclivity or ignition propensity characteristics. A further object of the present invention is to provide a smoking article wherein the mechanism for improving the ignition proclivity does not adversely affect the release of smoke or flavor. Still a further object of the present invention is to provide a wrapping for the smoking article which significantly reduces the proclivity or propensity of ignition of a smoking article without adversely affecting the smoking characteristics. Additional objects and advantages of the invention will be described in part in the following description, or they will be obvious from the description, or they may be instructed through the practice of the invention. In order to achieve the objects and in accordance with the purposes of the invention, which form the body and are broadly described herein, a smoking article comprising a column of tobacco and a tobacco column is provided. wrapping around the tobacco column. The envelope comprises discrete areas of reduced permeability to improve the characteristics of proclivity to ---. To ignition d? ± ar-.?cux? for --- umar. The R ---------------- H - ---- / - 'i "----! --- 3 s -H ---- r .---- - rm ----. -ah - í ~ | -. rl--> H raHupiH-i -------- n ?? -_- í.? n define as steering bands cross-section of the smoking article The areas of reduced permeability define a profile of permeability that changes gradually For example, the profile can gradually decrease in a uu? lc? -, -, xu? i ue i-.uul-ju - i i. It is important that a change in pearmibility of the areas of reduced permeability increases from a reduction in permeability of zero to a reduction in maximum permeability in the direction of burning of the article for smoking. . The article for smoking according to the invention may additionally include a reduced maximum permeability reduction area following the gradually decreasing permeability profile. The smoking article may also include a permeability profile 0 which gradually increases following the profile of permeability decreasing gradually in the combustion direction of the smoking article with an area of sustained maximum permeability reduction between the permeability profiles 5 which gradually decrease and increase gradually. For example, discrete areas can take a profile in the form of an ascending ramp and a descending ramp. The discrete areas of reduced permeability may comprise areas treated with a d-e film forming solution to reduce the permeability of the wrapper of the smoking article in the treated areas. The film-forming solution can comprise any type of solution which, when dried, forms a film which reduces the permeability of the article cover for smoking to a level necessary to reduce the proclivity to ignition, or the tendency of the article to smoking to self-extinguish if it is left on-or it is given, falling on a flammable substrate. For example, the solution may comprise an aqueous solution or a non-aqueous solution. The non-aqueous solution may be a solution of a solvent soluble cellulosic polymer, dissolved in a non-aqueous solvent. The solution may also comprise a non-reactive, particulate filler material to "increase or improve the film-forming capacity of the solution." The discrete treated areas, especially in the embodiment wherein the areas comprise ramp-shaped bands, shall have a width that ensures that the The smoking article will self-extinguish once the burning coal of the smoking article advances in the treated area. The width of the treated area is, therefore, a function of the permeability reduction of. treated area. A desired range of permeability for sustained permeability reduction to the maximum of the treated areas is less than 6 ml / min / cm 2, and generally within a range of essentially 2 to 6 ml / min / cm 2. In this range the maximum permeability area preferably has a length of at least 4 mm. The present invention also relates to an article wrapping for uir-ar, such as a cigarette paper, having discrete areas of reduced permeability to improve control of ignition proclivity of a smoking article. The areas of reduced permeability are essentially as described above with respect to the smoking article according to the invention. The appended drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1- is a perspective view of a smoking article, specifically a cigar, according to the invention; Figure 2 is a component view of the smoking article of Figure 1 particularly illustrating the treated areas of the cigar wrap. Figure 3 - is a perspective view of a smoking article according to the invention particularly illustrating the areas treated in the form of a ramp; Figure 4 is an exploded view of the cigarette wrap shown in Figure 3 particularly illustrating the ramp-shaped profiles of the treated areas; Figure 5 is a cross-sectional view of the envelope shown in Figure 4 taken along the indicated lines; Y Figure 6a and 6b are alternating transverse views of the areas treated in the form of ramps formed in the wrapping of the smoking article.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Reference is now made in detail to the presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by means of the explanation of the invention, not as a limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used in another embodiment to provide a still further modality. A) Yes, it is intended that the present invention cover such modifications and variations that are within the scope of the appended claims and their equivalents. Figures 1 and 2, and the following discussion with them, relate to a preferred non-aqueous solution for treating discrete areas of the smoking article wrap to reduce the permeability of the wrap in the treated areas, at a level which tends to cause the smoking article to self-extinguish or autoapay according to the mineral Burning of the article for smoking progresses within the treated areas. The discussion of FIGS. 1 and 2 particularly relates to an aqueous ps solution which applicants have found to be particularly convenient for the present invention. In Figures 1 and 2, the treated areas are applied as separate bands spaced along the length of the smoking article. The bands of this modality do not necessarily incorporate increase or decrease of the permeability profiles in accordance with Figures 3-6, as will be fully discussed below. However, the non-aqueous film-forming solution discussed below in reference to FIGS. 1 and 2 pertains to the present invention, so that the respective non-aqueous film-forming solution is preferred in forming the inventiveness of the bands. in the form of a ramp in accordance with the invention. It should be understood, however, that the present invention related only to the bands or areas formed of reduced permeability, is not limited and, in any way with the non-aqueous solution discussed at this point. The present invention relates to a unique form or model for discrete areas which can be formed from any way of film forming solutions, including aqueous and non-aqueous solutions. The discussion here refers to aqueous solutions provided by means of the explanation of the invention, and as an illustration of a preferred embodiment of a particularly employed solution. It could be understood by those skilled in the art that any form of film forming solutions are within the scope and spirit of the invention. For example, the prior art describes the application of syrups and / or any form of film-forming solutions for cigarette papers to reduce permeability and control the smoking ratio of the cigar. Aqueous solutions which have been found to be effective include aginate, pectin, carboxymethylcellulose and polyvinyl alcohol. Fibrous syrups - applied from aqueous solutions are also effective. These include microcrystalline cellulose, cellulose bacterial cellulose, and highly refined pulpwood fiber. Also, natural polymers soluble in non-aqueous solvents are also effective. All and any of the solutions are within the scope and spirit of the claimed invention.

For purposes of explanation of the invention, the embodiments and principles of the invention will be described with respect to a cigarette. However, this is only for purposes of explanation of the invention and does not mean that it limits the invention only to cigarettes. Any form of the article for smoking is within the scope and spirit of the invention. The invention relates to an article for smoking, and to an enclosure for an article for smoking, which has enhanced proclivity control or inclination to ignition characteristics. "Proeliness or propensity to ignite" is a measure of the tendency of the smoking article or cigarette to ignite or ignite a flammable substrate if the cigarette that is burned or smoked is dropped or otherwise left on a substrate flammable. A test for the ignition proclivity of a cigarette has been established by NIST (National Institute of Standards and Technology) and involves placing a smoldering cigarette on a flammable test cloth and recording the Cigarette tendency to either burn the texture or fabric test, burn the test texture beyond a normal carbon line of the texture or fabric, burn its length Complete without igniting the fabric or texture, or self-extinguishing before igniting or igniting the test cloth by burning its full length. A preferred embodiment of the invention is generally illustrated in Figures 1 and 2. An article for smoking (cigarette), generally 10, having improved ignition proclivity characteristics include a tobacco column 12 within a wrapper 14. The article 10 may include a filter 26. The wrapper-14 may include any commercially available form of cigarette wrapper, such as 603 grade KC paper by Kimberly-Clark Corporation. It should be understood that any other form of paper web can be used in regard to this. The paper web 14 defines an outer circumferential surface 16 when wrapped around the tobacco column 12. The discrete areas 18 of the outer circumferential surface 16 are treated with a non-aqueous solution. This solution includes a solvent-soluble cellulosic polymer material dissolved in a non-aqueous solvent. The solution also includes a particulate inorganic non-reactive filler worn or suspended in the solution, as described more fully below.

It should also be understood that the treated areas 18 could be placed on the inner surface of the weft 14 so that they are adjacent to the tobacco column 12. In the illustrated embodiment, the treated areas 18 are defined as or transverse direction bands. circumferentially, 24. The strips 24 separate from each other longitudinally along the length of the cigarette 10. The strips 24, and particularly the fine particulate filler 22 are indicated in phantom in Figure 2. However, it should be understood that the The treated areas are essentially invisible in the cigarette formed as shown in Figure 1. In other words, a smoker can not distinguish from any external signal that the wrapper 14 has been treated in discrete areas 18. With respect to this, the treated areas 18- have a smooth and flat or smooth texture essentially the same as the untreated areas 28. The treated areas 18 ro bands 24 r have a permeability den of a range which is known to provide improved ignition proclivity or propensity characteristics for the manufacture of the cigarette 10. When the charcoal of the cigarette 10 is burned within one of the bands 24, the oxygen available for the charcoal combustion reduces substantially due to the decrease in permeability of the wrapper 14 in the treated areas. Oxygen reduction causes the cigarette to self-extinguish or self-abate in the treated areas 18. Applicants have determined that a preferred permeability is less than 6 ml / min / pm2 (CORTESA), and generally within a range of 2 to 6 ml / min / cm2. Applicants have found that this range provides the desired self-extinguishing results when burning the mineral coal from the cigarette in the treated areas. - The width and spacing of the bands 24 are dependent on a number of variables, such as the initial permeability of the envelope 14, density of the tobacco column 12, etc. The bands 24 preferably have a width such that the oxygen is limited to the charcoal burned for a length or period of time sufficient to extinguish the mineral coal. In other words, if the strip 24 were so narrow, the combustion coal could burn through the strip 24 before self-extinguishing. The applicants have determined that, for the cigarettes tested, a minimum bandwidth of 4 mm is desired.

The spacing between bands 24 is also a factor of a number of variables. The spacing should not be greater than the cigarette that is burned for a length or time sufficient to ignite or ignite a substrate before the charcoal ever burns in a treated area 18. The spacing between the bands 24 also affects the thermal inertia of the combustion mineral coal, or the capacity of the mineral coal to ignite or ignite through the treated bands 24 without self-extinguishing. In other words, the spacing between the bands 24 should not be greater than the combustion mineral coal burned sufficiently hot and fast enough to burn through one of the bands 24 when they come into contact with the respective band. On the other hand, the spacing between bands 24 should not be less than the cigarette which tends to extinguish or self-extinguish in a free combustion state. In tested cigarettes, applicants have found that a spaced band of between 5 and 10 mm is appropriate. However, it should be understood that the band spacing can be any suitable width as determined by any number of variables.

The solution - applied to wrap 14 in treated areas 18 provides reduced permeability in the treated areas. Applicants have found that a non-aqueous solution of a solvent soluble cellulosic polymer with a non-reactive particulate inorganic filler suspended in the solution works particularly well. The non-aqueous solvent tends not to interrupt the inter-fiber bonding (eg, hydrogen bonding) of the paper web andThus, the resistance of the paper web does not significantly decrease. Also, the non-aqueous solvent does not cause the paper web to wrinkle or shrink when the solvent dries. This allows the wrap 14 to have a smooth or smooth and aesthetically pleasing appearance. Applicants have found that a particularly suitable non-aqueous solvent is a mixture of an alcohol and an acetate, for example a 50/50 mixture of isopropyl alcohol and ethyl acetate. However, it should be understood that this is but a preferred solvent, and any suitable non-aqueous solvent or solvent mixture can be used in connection with this.; For example, a 60/40 mixture of normal propyl acetate and normal propyl alcohol It has also been shown to work particularly well. Applicants have also found that a suitable solvent soluble cellulosic polymer is ethyl cellulose. Ethyl cellulose is generally in a concentration of about 15% to 35% by weight of solution, and preferably about 25% by weight of solution. However, any cellulose-based polymer can be used in this case, including hydroxypropyl cellulose. A non-reactive inorganic particulate filler 22 is added to the solution. Applicants have found that the filler 22 significantly improves the ability of the treated areas 18 to self-extinguish or auto-off the combustion coal. The solution with the filler is more effective in reducing the permeability of the paper web in treated areas 18. Applicants believe that the inorganic filler 22 forms a layer on the envelope surface 14 with the ethyl cellulose which acts as a binder or glue "for the filler particles. Applicants believe that the filler particles tend not to collide or strike with the pores of the casing 16 and form a relatively smooth surface coating. The filler and the cellulose polymer form a coherent and smooth surface coating which significantly reduces the permeability of paper in the treated areas. It is also believed that the solution containing the inorganic filler particles is less affected by the heat of the combustion cigarette, thus ensuring that the coating remains intact so that it is effective in restricting oxygen to the burning coal. Any number of inorganic re-binders may be suitable in the present invention. Any filler material can be used which can be spent homogeneously in the non-aqueous solution to form a surface film with the cellulosic polymer without affecting the texture or appearance of the wrapper. Applicants have found that particularly good fillers are chalk, clay, and titanium oxide. The present invention also pertains to a wrapping of the smoking article for use with smoking articles, as essentially described above, as well as a method for making the wrapping of the smoking article. The inventive method for producing the wrapping of the smoking article having control characteristics of Improved ignition proclivity includes applying a non-aqueous solution of a cellulose polymer that forms the film and non-aqueous solvent with an inorganic particulate filler suspended in the solution for an article of smoking article in discrete treated areas , such as bands 24 as described above. The treated areas are then dried so that essentially all of the non-aqueous solvent is removed leaving a film of the cellulosic material and filler material on the paper in treated areas 18. The method includes applying the non-aqueous solution so that the treated areas 3 dry. have a permeability within the known range to cause self-extinction or self-extinguishing of the cigarettes, for example, within a range of 2 to 6 ml / min / cm2. The method also includes printing the solution in the paper web in the discrete areas by means of conventional high speed printing operations. Applicants have found that suitable printing techniques include printing by gravure and flexographic printing. The treated areas can be applied in printing operations in either single pass or multiple pass. Accordingly, the viscosity of the solution is controlled to be adequate with high-speed printing techniques. Applicants have also found that the desired white permeability ranges are easily achieved by applying the solution to areas treated in multiple passages with conventional printing machines. Nevertheless, it is also possible to achieve the desired permeability range by applying the solution in a single step and controlling the viscosity and amount of solution applied. The following examples relate to cigarettes produced according to the invention and are provided to more fully explain the invention. In each of the examples, the coating is applied in a three step process without intermediate drying. The base paper was grade 603 Kimberly-Clark paper with an average untreated permeability of 32.6 ml / min / cm2. The viscosity measured for the solution was 45 seconds using a Zahn Cup # 2 Viscometer.

EXAMPLE 1 In a first series, the clay ALPHATEX (Clay China Anhydrous) by Anglo-American Clay Corporation, was added to a base solution of ethyl cellulose (approximately 25% by weight of solution) was dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. A 10 mm band of solution was printed in a three-step process on a 5 KC Grade 603 Kimberly-Clark paper, base, with an initial average porosity of 32.6 ml / min / cm2. The clay was added to 3% by weight of solution with a coating weight of the treated areas of 3.0 g / m2. The average permeability of this set of 10 cigarettes was 3.1 ml / min / cm2. Three of three tested cigarettes were self-extinguished or self-extinguished EXAMPLE 2 1 t-. X - I In a second series, the ALPHATEX clay (China Anhydrous Clay) by Anglo-American Clay Corporation was added to a base solution of ethyl cellulose (approximately 25% by weight of solution), dissolved in a 60/40 mixture of normal propyl acetate and normal propyl alcohol. A 10 mm band of solution was printed in a three step process on a KC Grade 603 base paper from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. The clay was added to 6% by weight of the solution. The Average permeability of this set was 1.6 ml / min / cm2. Four out of four tested cigarettes were self-extinguished or autoapaged at or near the coated area.

EXAMPLE 3 In a third series, Ti02 was added to a solution of ethyl cellulose base (approximately 25% by weight of solution) was dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. Ti02 was added in the form of a white ink. The ink was approximately 10% Ti02 with a nitrocellulose binder. A 10 mm band of solution was printed in a 3 step process on a KC Grade 603 base paper from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. The Ti02 was added to 0.5% by weight of the solution with a coating weight of the treated areas which was 3.4 g / m2. The average permeability of this set was 3.2 ml / min / cm2. Four of four tested cigarettes self-extinguished to self-extinguish at or near the coated area.

EXAMPLE 4 In a fourth series, Ti02 was added to a solution of ethyl cellulose base (approximately 25% by weight of solution) was dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. Ti02 was added in the form of a white ink. The ink was approximately 10% Ti02 with a nitrocellulose binder. A 10 mm band of solution was printed in a 3-step process on a base paper .KC Grade 603 from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. The Ti02 is added to 1.0% by weight of solution with a coating weight of the treated areas which is 4.2 g / m2. The average permeability of this set was 1.8 ml / min / cm2. Four out of four tested cigarettes self-extinguished or self-extinguished in or near the coated area. EXAMPLE 5 In a fifth series, Ti02 was added to an ethyl cellulose base solution (approximately 25% by weight of solution) dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. Ti02 was added in the form of a white ink. The ink was approximately 10% Ti02 with a nitrocellulose binder. A 10 mm band of solution was printed in a 3 step process on a KC Grade 603 base paper from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. Ti02 was added to 1.2% by weight of solution with a coating weight of the treated areas of 4.7 g / m2. The average permeability of this set was 0.91 ml / min / cm2. Four out of four tested cigarettes self-extinguished or self-extinguished in or near the revived area.

EXAMPLE 6 In a sixth series, Ti02 was added to a solution of ethyl cellulose base (approximately 25% by weight of solution) was dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. Ti02 was added in the form of a white ink. The ink was approximately 10% Ti02 with a nitrocellulose binder. A band of 10 mm solution was printed in a 3 step process on a KC Grade 603 base paper from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. The Ti02 was added to -2.5% by weight of solution with a coating weight of the treated areas which is 4.9 g / m2. The average permeability of this set was 0.74 ml / min / cm2. Since the permeability of this set was less than 0.91 of Example 5, it was not necessary to test the ignition proclivity. It was fully expected that any cigarettes treated with the composition could self-extinguish.

EXAMPLE 7 In a seventh series, Ti02 was added to a solution of ethyl cellulose base (approximately 25% by weight of solution) was dissolved in a mixture of 60/40 of normal propyl acetate and normal propyl alcohol. Ti02 was added in the form of a white ink. The ink was approximately 10% Ti02 with a nitrocellulose binder. A 10 mm band of solution was printed in a 3 step process on a KC Grade 603 base paper from Kimberly-Clark with an initial average porosity of 32.6 ml / min / cm2. Ti02 was added to 5-0% by weight of solution with a weight of coating of the treated areas that is 9.7 g / m2. The average permeability of this set was 0.29 ml / min / cm2. "Since the permeability of this set was less than 0.91 of Example 5, it was not necessary to test the ignition proclivity." It was fully expected that any cigarettes treated with the composition could self-extinguish.

EXAMPLE 8 In another series, MULTIFLEX chalk (precipitated calcium carbonate) from Specialty Minerals, Inc. was added to a solution of ethyl cellulose base (approximately 25% by weight solution) in a 50/50 solvent of normal propyl acetate and normal propyl alcohol. The chalk was added to 9% by weight of solution. 5 mm transverse direction webs were printed on a KC Grade 603 base paper from Kimberly-Clark with an average initial porosity of 32.6 ml / min / cm2 in a three-step gravure printing operation. The average permeability for the treated areas was less than 2 ml / min / cm2. In proclivity or ignition propensity tests conducted on a # 4 cotton canvas material with a film underneath, 3 of 5 cigarettes were self-extinguished or self-extinguished and 1 cigarette burned its full length without igniting the substrate. In the test conducted on a # 6 non-film cotton canvas material, 1 of 6 cigarettes was self-extinguished. "In this test, it seems that the bandwidth of 5 mm was not enough to extinguish the cigarette and the spacing of the 10 mm band was too large to prevent a fire or ignition, although, as discussed above, the printing of The transverse direction (CD) strips of reduced permeability materials in cigarette paper have been shown to be effective in reducing the permeability and propensity to ignite cigarettes, such bands can also have a discontinuous effect undesired in the release of smoke and smoke flavor.These undesired effects may nevertheless exist in the type of solution used to form the bands.For example, if the change in permeability between the treated areas3 and untreated areas of the cigar is relatively greater, the smoker will understand a difference in the release of smoke and flavor.The solutions applied can sometimes also affect the taste of the cigar. The present invention also relates to a single purpose or profile for the transverse direction bands to minimize the effect of the bands in the release. of smoke and flavor to the smoker. The present unique purpose for the bands provides a more uniform release of smoke over the entire length of the cigarette. Referring particularly to Figures 3 and 4, a smoking article 10 is illustrated, in accordance with the invention. Again, the smoking article 10 is illustrated as a cigarette but this does not mean a limitation of the invention. The smoking article 10 includes a tobacco column 12 around a paper wrapper 14. The wrapper 14 defines a circumferential outer surface 16 of the smoking article. The surface 16 has discrete treated areas 18 defined thereon to reduce the permeability of the sheath 14, as discussed in detail above with reference to Figures 1 and 2. It should also be appreciated that the treated areas 18 could also be defined on the inner surface of the weft 14 as well as being adjacent to the tobacco. In use, the smoking article 10 is smoked by a smoker at the end 13 and has a burn direction 32 towards the filter 26, as will be commonly understood in the art. As the burning coal of the smoking article advances in the 32nd direction, it eventually suggests the treated areas. or bands 24. The treated areas 18 are separated or spaced by themselves from the untreated areas 28. In addition, the mineral carbon alternates in this progression from the treated areas to the untreated areas. In accordance with the invention, the treated areas of reduced permeability define a gradual decrease in the permeability profile 30 in the burning direction 32. The gradually decreased permeability profile 30 is defined so that the combustion mineral carbon does not occupy the maximum permeability reduction of band 24 all ever, burn gradually within the area of maximum permeability reduction. In this way, the change in the release of flavor and smoke to the smoker occurs over a gradual period and is less detectable to the smoker. With particular reference to Figure 4, the profiles of the bands 24 are particularly illustrated. It can be easily seen how a burning coal of the cigarette advances in the direction 32, its first outlet area 30 of permeability decreases gradually. In other words, the thickness of the permeability reduction film increases from a minimum point 34 to a maximum point 36. As the film increases in the thickness between points 34 and 36, the permeability of the paper also gradually decreases until it reaches a minimum permeability, or area of greatest reduction of permeability to point 36. The mineral carbon will then return or advance through a maximum reduction area 38 sustained Figure 4 graphically illustrates two types of bands. The first band is shown in dotted lines, it attempts to illustrate a film formed by any type of film-forming solution, such as an aqueous solution, non-aqueous solution, or other solution. The second band 24 shown in the burning direction 32 attempts to illustrate a band formed with the non-aqueous solution of a solvent-soluble cellulosic polymer dissolved in a non-aqueous solvent with a non-reactive particulate filler 22 spent in the solution, as described in FIG. detail with reference to figures 1 and 2. However, it should be understood that the benefits of the single profile of permeability gradually decreased, can be realized considering the type of solution used to form the bands 24. The area of sustained permeability reduction 38 preferably has a width which is Sufficiently greater to cause the cigar to self-extinguishing if it falls or otherwise remains in the flammable substrate. The amplitude of the area 38 depends on a number of variables, including the permeability of the treated area, type of base paper, space between the bands, etc. The amplitude of the bands 24 and the spaces between the bands 24 can vary accordingly. Applicants have found that, if the maximum permeability reduction area is within a range of 2 to 6 ml / min / cm 2, an amplitude for area 38 should be at least 4 mm. Also, as discussed above in detail with respect to Figures 1 and 2, the space between the bands is also an important consideration. The spaces shall not be greater when the combustion coal is ignited in a flammable substrate before its advance even within a treated area. Also, the space must not be greater than the combustion coal generated sufficiently by inertia to burn through the treated areas before self-exiting. As particularly shown in Figures 4 and 5, the bands 24 may also include an increased permeability area 40 gradually followed by areas 30 and 38 in the burning direction 32 of the cigarette. Permeability areas 40 Increasing gradually, they allow the mineral coal to advance gradually to burn within the untreated areas 28 without generating an abrupt change in the release of smoke or flavor. Figure 6a illustrates a mode where the band 24 includes only a gradually enhanced permeability area 30 in the burning direction 32 of the cigarette. Similarly, Figure 6b illustrates a mode wherein the band 24 includes only one area 40 of increased permeability. The areas of change permeability 30, 40 may have relatively smooth or flat profiles, such as those shown in the drawings, wherein the bands 24 have a profile in the form of an upward ramp and / or in the form of a downward ramp. Applicants have found that this type of profile can be applied directly to wrappers 14 by direct commercial printing techniques such as gravure printing or flexographic printing. The treated areas can be applied in a multiple pass or one step operation depending on the amount of solution applied and the viscosity of the solution. In an alternative embodiment not particularly illustrated in the figures, the areas of permeability increase and decrease 30, 40 may comprise a profile of ascending step and / or descending step. In other words, the bands 24 could be formed by layers having a width decremented successively. This type of band could be applied in a multiple step of gravure or flexographic printing operation. The following examples of cigarettes having CD bands formed in accordance with the present invention are provided below for purposes of illustration and explanation of the invention.

EXAMPLE 9 In this series, CD-shaped ramp bands were printed on a Grade 603 paper by Kimberly-Clark. The model or ramp shape consists of an area in the form of an ascending ramp of 2.5 mm which is gradually increased from 0% to 100%. An area of 5 mm maximum coverage 100% continues to the area in the form of an upward ramp. An area in the form of a descending ramp of 2.5 mm with a coating decreasing from 100% to 0% continues to the area of 5 mm of maximum sustained coverage. The model or ramp shape is engraved or not engraved on a paper and used for printing Cigarette papers in a commercial tax pressure in a 3 step process. The solution used was ethyl cellulose (approximately 25% by weight of solution) in a 50/50 solvent of normal propyl acetate and normal propyl alcohol with Multiflex chalk added to 9% by weight of solution. With the Multiflex chalk filler, the viscosity of the solution was 39 seconds in the glass. The bands were printed at a space of 10 mm. In proclivity or propensity to ignition tests conducted on a # 4 cotton canvas material with a film underneath, 6 of 6 cigarettes were self-extinguished. In tests conducted on a non-film # 6 cotton canvas material, 3 of 6 cigarettes were self-extinguished. It will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope and spirit of the invention. For example, the dimensions of the ascending ramp and descending ramp sections and maximum permeability reduction area can be varied in accordance to achieve the desired results. Additionally, the treated areas can be formed by any form of solution, including aqueous and non-aqueous solutions. Thus, it is intended that the present invention cover the modifications and variations of this invention provided, they come within the scope of the appended claims and their equivalents.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following

Claims (10)

1. CLAIMS 1. A smoking article characterized in that it comprises a taoaco column, and a wrapping around said tobacco column, the wrapping comprises discrete areas of reduced permeability to improve the characteristics of proclivity or propension to the ignition of said smoking article, areas of reduced permeability define a permeability profile gradually decreased in a burning direction of said smoking article so that the reduction of permeability in the areas of reduced permeability are increased from a minimum zero permeability reduction to a maximum permeability reduction in that direction of burning.
2. 2. The smoking article according to claim 1, characterized in that it also comprises an area of sustained maximum permeability reduction followed by the permeability profile gradually decreased in said burning direction.
3. 3. The smoking article according to claim 2, characterized in that the discrete areas of reduced permeability comprise a substantially ramp-shaped profile.
4. 4. The smoking article according to claim 1, characterized in that said discrete areas of reduced permeability further comprise a gradually increased permeability profile followed by the permeability profile gradually decreased in the burning direction of the smoking article.
5. 5. The article for smoking according to claim 4, characterized in that it also comprises an area of sustained maximum permeability reduction between the gradual increase and the gradually decreased p-ability profile.
6. 6. The article for smoking according to claim 5, characterized in that the discrete areas of reduced permeability comprise a profile substantially in the form of ramp with an increased and decreased ramp section.
7. 7. The article for smoking according to claim 1, characterized in that the discrete areas of reduced permeability comprise areas treated with a film-forming solution.
8. 8. The article for smoking according to claim 7, characterized in that the treated areas comprise areas treated with an aqueous film-forming solution.
9. 9. The article for smoking according to claim 7, characterized in that the treated areas comprise areas treated with a non-aqueous solution of a solvent-soluble cellulosic polymer dissolved in an aqueous solvent.
10. 10. The smoking article according to claim 9, characterized in that the solution further comprises a non-reactive particulate filler material. Corrupted TIFF IMAGE: no OCR available gradually changing in a burning direction which is perpendicularly essential to a longitudinal axis of said envelope so as to be permeable in said area of change permeability, changing from zero permeability reduction to a maximum permeability reduction. 15. The wrapping of the smoking article according to claim 14, characterized in that said change permeation profile comprises a profile of permeability gradually decreased in said burning direction so that the reduction of permeability in said areas of reduced permeability is increased by a Permeability reduction - Zero to a maximum permeability reduction. 16. The wrapping of the smoking article according to claim 15, characterized in that it also comprises an area of sustained maximum permeability reduction followed by the profile of permeability gradually decreased. 17. The wrapping of the smoking article according to claim 14, characterized because the discrete areas of reduced permeability comprise transverse direction bands having a substantially ramp-shaped profile on at least one of the sides thereof. 18. The wrapping of the smoking article according to claim 15, characterized in that the discrete areas of reduced permeability further comprise a permeability profile gradually increased followed by the profile of permeability gradually decreased in the direction of burning of said wrapping. 19. The wrapping of the smoking article according to claim 18, characterized in that it also comprises an area of sustained maximum permeability reduction between said permeability profiles gradually increased and gradually decreased. 20. The wrapping of the smoking article, according to claim 19, characterized in that said discrete areas of reduced permeability comprise a profile substantially in the form of ramp with an increased and decreased ramp section. 21. The wrapping of the smoking article according to claim 14, characterized in that the discrete areas of reduced permeability comprise areas treated with a film-forming solution. 22. The wrapping of the smoking article according to claim 21, characterized in that said treated areas comprise areas treated with an aqueous film-forming solution. 23. The wrapping of the smoking article according to claim 21, characterized in that said treated areas comprise areas treated with a non-aqueous solution of a solvent-soluble cellulosic polymer dissolved in a non-aqueous solvent. 24. The wrapping of the smoking article according to claim 23, characterized in that said solution further comprises a non-reactive particulate filler material. 25. The wrapping of the smoking article according to claim 14, characterized in that said discrete areas of reduced permeability comprise a maximum reduced permeability area of at least 6 ml / min / cm2. 26. The wrapping of the smoking article according to claim 25, characterized in that said maximum reduced permeability area has a length of at least 4 mm. 27. The wrapping of the smoking article according to claim 26, characterized in that the discrete areas of reduced permeability comprise a plurality of spaced-apart bands placed around the smoking article, said bands having ramp-shaped edges with the area of reduced permeability maximum between the edges in the form of a ramp.