Smoking articles using novel paper wrapper

Abstract: The calcium carbonate filler level or the basis weight of a paper wrapper for a smoking article is varied to enable the designing of smoking articles with specific characteristics including a specific puff count, tar delivery and carbon monoxide delivery.

Description: Background Of The Invention This invention relates to a smoking article, such as a cigarette, using a paper wrapper with a novel construction. Specifically, the smoking article of the invention uses wrappers which alter the characteristics of the smoking article including puff count, tar delivery and carbon monoxide delivery by adjustment of the paper wrapper's calcium carbonate filler level and of the paper wrapper's basis weight. These adjustments of the paper wrapper combined with changes in filter, paper porosity, burn control additive, or tobacco blend characteristics can be used to design specific smoking articles. Cigarette paper has traditionally been used in the cigarette industry to control a number of properties of the completed cigarette including puff count, mainstream tar delivery and mainstream carbon monoxide delivery. In virtually all cases, however, changes to the cigarette paper have been restricted to two properties of.the paper: paper porosity and level of burn control additive. The relationship of porosity to cigarette performance is well understood by the industry. For instance, as inherent paper porosity is increased, puff count and, therefore, total tar delivery, decrease. Tar per puff remains approximately constant. If, however, paper porosity is increased through perforation of the paper (increase in paper permeability), then puff count increases and tar per puff decreases due to air dilution during the puff. Paper porosity also has an effect on mainstream carbon monoxide delivery. As porosity increases, mainstream carbon monoxide declines due to increased diffusion through the paper during smoking. Level of burn control additive is also used to control tar and puff count. Increasing burn control additive over the range typically used (0.5% to 3.0%), increases burn rate, lowers puff count and decreases total tar delivery. Research disclosure, No. 316, August 1990, page 647, Emsworth Hampshire, abstract No. 31673, discloses a cigarette exhibiting a reduced side stream smoke, in which a paper wrapper of permeability between 20 and 50 Coresta units, and a calcium carbonate filler content of less than 20% by weight. US 4,984,589 discloses a self extinguishing cigarette having a laminated wrapper formed by the wet lamination of two paper pulps. The porosity of the laminated wrapper is low, so that the burning of the tobacco is practically stopped when the cigarette is not being smoked. The adjustment of porosity and the filler and burn promoter contents in order to achieve satisfactory smoking of the cigarette is disclosed. US 4,998,543 discloses a dual wrapper cigarette, exhibiting reduced side stream smoke. The outer wrapper has a basis weight of about 30 to 70 g/m 2 , an initial porosity of about 2 to 10 Coresta units and a calcium carbonate filler loading of about 30 to 40%. The inner wrapper has different characteristics, and the characteristics of the combined wrapper are not disclosed. In all cases, these changes in the specifications of paper properties can be combined with changes in the specifications of filter properties to obtain a change in the final design of the cigarette. For instance, should one choose to increase the tar per puff, and therefore the subjective impact of a low delivery cigarette, without changing the total tar delivery, one can increase paper porosity (or level of burn control additive) to decrease puff count and then decrease filter efficiency or filter dilution in order to restore the total tar delivery to its former value. By the same token, if one desires to increase puff count and leave the total delivery constant, then one can decrease paper porosity (or level of burn control additive) to increase puff count, and then increase filter efficiency or dilution to lower the tar per puff. There are many examples known to the art where these types of paper porosity, burn control additive level and filter manipulations are carried out in order to achieve a desired cigarette design. Despite the flexibility which can be achieved in cigarette design through the manipulation of paper porosity and level of burn control additive, there are instances when a desired cigarette design cannot be optimally achieved by controlling either of these two paper properties. Many examples are in the area of low delivery cigarettes; however, there are certain examples in the category of full flavor cigarettes as well. An example of a cigarette which cannot be achieved using normal practices would be an ultra low delivery cigarette (2 mg tar for a 100 mm cigarette) with reasonable taste characteristics. The puff count necessary to achieve this objective is about 7. Even with paper of essentially maximum porosity (46-50 Coresta units), and a high level of burn control additive, it is not possible to obtain less than 7.5 puffs. Furthermore, controlling a cigarette's properties by the addition of burn control additives creates unwanted effects. High levels of burn control additive have been shown to increase the tendency of an ash to flake. High levels of burn control additive or changing paper porosity or filter ventilation may also produce an undesired decrease in the subjective impact of the smoking article including less taste. The subjective impact is also often sacrificed if a low tar delivery cigarette is designed with a tobacco blend to lower the tar delivery. Thus, it would be desirable to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired puff count. It would also be desirable to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired tar delivery. It would further be desirable to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired carbon monoxide delivery. It would further be desirable to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with certain desired characteristics that does not require high levels of burn control additive, changes in tobacco blend, changes in paper porosity or changes in filtration ventilation or efficiency. It would further be desirable to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with certain desired characteristics without excessively decreasing the subjective impact, such as taste, of the smoking article. Summary Of The Invention It has been desired to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired puff count. It has also been desired to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired tar delivery. It has also been desired to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with a desired carbon monoxide delivery. It has also been desired to provide a smoking article with a paper wrapper that can be used to achieve a smoking article with desired characteristics without high levels of burn control additive or major changes in tobacco blend and without excessively decreasing the subjective impact of the smoking article. According to the invention there is provided a smoking article comprising a tobacco filler surrounded by a single paper wrapper, the paper wrapper having: a calcium carbonate loading of between 30% by weight and 40% by weight; a basis weight of between 28 g/m 2 and 35 g/m 2 ; and an inherent porosity of between 40 Coresta units and 55 Coresta units and including between 0.5% by weight and 3.0% by weight of an alkali metal salt as a burn control additive. Also according to the invention there is provided a method of altering the puff count of a smoking article having a single paper wrapper comprising the steps of: (a) establishing in a paper wrapper having: a calcium carbonate loading of between 30% by weight and 40% by weight; a basis weight of between 28 g/m 2 and 35 g/m 2 ; and an inherent porosity of between 40 Coresta units and 55 Coresta units and an alkali metal salt content between 0.5% by weight and 3% by weight as a burn control additive; (b) wrapping a tobacco filler for the smoking article in said paper wrapper. Smoking articles, such as cigarettes, according to the invention have a paper wrapper with a calcium carbonate level or basis weight that it varied to produce changes in puff count, tar delivery or carbon monoxide delivery of the cigarette. These characteristics or cigarettes can be changed by varying the calcium carbonate level or basis weight of the paper with or without making changes in paper porosity or burn control additive levels in the paper or by changing filter characteristics or the tobacco blend. Making these changes in a cigarette's characteristics allows the design of desired cigarettes without the use of excessively high levels of burn control additives. This invention also makes it possible to achieve designs of cigarettes which could not be done through variations of paper porosity, burn control additive and filter characteristics alone. Specific designs of smoking articles can be achieved with this invention while improving or not excessively decreasing the subjective impact of the smoking article. The paper wrapper of this invention may be used for smoking articles of any length or circumference and having different fillers such as tobacco, expanded tobacco, a variety of blend types, reconstituted tobacco materials, stems, non-tobacco filler materials and combinations thereof. The paper wrapper of this invention is especially suited for use with expanded tobacco fillers because there is no need for excessively high levels of burn control additives. Detailed Description Of The Invention The paper wrapper of this smoking article invention may be made from flax or other cellulosic fibers. Between about 30% by weight and about 40% by weight of calcium carbonate is used as a filler. Preferably between about 30% by weight and about 36% by weight of calcium carbonate is used. The paper wrapper should also have a basis weight of between about 28 g/m 2 and about 35 g/m 2 , preferably between about 28 g/m 2 and about 35 g/m 2 . In addition, the inherent porosity of the paper wrapper is between about 40 Coresta units and about 55 Coresta units. Such a high porosity wrapper can achieve low tar delivery. The paper is treated with between about 0.5% by weight and about 3.0% by weight of a burn control additive. Such a burn control additive is an alkali metal salt, preferably a citrate such as potassium citrate. Sodium or potassium acetate, sodium or potassium fumarate, sodium or potassium succinate, sodium or potassium phosphate or other salts or mixtures thereof may be used. The purpose of the burn control additive includes improving ash characteristics and controlling puff count and the optimum level depends on the specific characteristics of the paper wrapper and the tobacco blend. Finally, a filter can be added to the smoking article which can alter and dilute the mainstream delivery. The filtration efficiency or the filtration ventilation level can be altered to adjust the mainstream delivery of the smoking article. Other ventilation means may also be used besides ventilation provided by filters. A particular example of such paper wrapper has a basis weight of 28 g/m 2 to 35 g/m 2 with a calcium carbonate filler loading of 25% by weight, a paper porosity of 47 Coresta units and a burn control additive level of 1.7% by weight. The invention will now be further explained, by way of example, with reference to data from individual cigarettes and data extrapolated from individual cigarettes. Data from cigarettes with about 20% expanded tobacco, a filter ventilation of 50% and with a paper wrapper with a basis weight of about 30 g/m 2 with about 30% by weight calcium carbonate, 1.7% by weight burn control additive and a porosity of about 46 Coresta units is presented below: Puff Count 7.2 Tar, mg 6.5 EXAMPLE 2 Filter ventilation can be decreased in order to provide improved subjective impact such as improved taste, without altering puff count or tar delivery. Decreasing filter ventilation will decrease puff count and increase tar delivery. Decreasing the level of calcium carbonate in the paper can be used to reestablish the original puff count. Any necessary adjustment to tar delivery can then be accomplished by changing filtration efficiency. The data below indicates that lowering the ventilation level for subjective impact purposes while maintaining tar and puff count can be accomplished by changing filter efficiency and reducing the level of calcium carbonate. 36% CaCO 3 36% CaCO 3 30% CaCO 3 Puff Count 7.4 7.2 7.4 Tar, mg 2.3 2.2 2.3 Ventilation, % 62 56 56 Filter Effic., % 77 80 80 The teachings in the above examples are in no way restricted by the actual design of tar level, carbon monoxide or puff count of the illustrated cigarettes. Thus it is seen that a paper wrapper for a smoking article, such as a cigarette, is provided that allows the design of smoking articles with specific characteristics such as a certain puff count, tar delivery or carbon monoxide delivery by changing the calcium carbonate level of the paper or the basis weight of the paper or. both. Designing particular cigarettes, then, requires only small changes, if any, to burn control additive levels, tobacco blend, paper porosity, filter efficiency or filter ventilation level. This avoids the negative effects on the ash and on the cigarette's subjective impact, such as taste, that can be caused by large changes to burn control additive level, tobacco blend, paper porosity and filter adjustments.

Claims: A smoking article comprising a tobacco filler surrounded by a single paper wrapper, the paper wrapper having: a calcium carbonate loading of between 30% by weight and 40% by weight; a basis weight of between 28 g/m 2 and 35 g/m 2 ; and an inherent porosity of between 40 Coresta units and 55 Coresta units and including between 0.5% by weight and 3.0% by weight of an alkali metal salt as a burn control additive. A smoking article according to claim 1 in which calcium carbonate loading of the paper wrapper is between 30% by weight and 36% by weight. A smoking article according to claim 1 or 2 in which the paper wrapper includes between 0.5% by weight and less than 1% by weight of an alkali metal salt as a burn additive. A method of altering the puff count of a smoking article having a single paper wrapper comprising the steps of: (a) establishing in a paper wrapper having: a calcium carbonate loading of between 30% by weight and 40% by weight; a basis weight of between 28 g/m 2 and 35 g/m 2 ; and an inherent porosity of between 40 Coresta units and 55 Coresta units and an alkali metal salt content between 0.5% by weight and 3% by weight as a burn control additive; (b) wrapping a tobacco filler for the smoking article in said paper wrapper. A method according to claim 4 in which the calcium carbonate loading of the paper wrapper is between 30% by weight and 36% by weight. A method according to claim 4 or 5 in which the paper wrapper includes between 0.5% by weight and less than 1% by weight of an alkali metal salt as a burn additive.

Inventors: ARTERBERY CYNTHIA W, BALDWIN SHERYL D, CLAFLIN WARREN E, FLOYD BARTON, GEISZLER WILLARD A, GOODMAN BARBRO L, MYRACLE JAMES L, SANDERS EDWARD B, ARTERBERY, CYNTHIA W., BALDWIN, SHERYL D., CLAFLIN, WARREN E., FLOYD, BARTON, GEISZLER, WILLARD A., GOODMAN, BARBRO L., MYRACLE, JAMES L., SANDERS, EDWARD B.
Applicants: PHILIP MORRIS PROD, PHILIP MORRIS PRODUCTS INC.
Application year: 1992
Main classification: A24D1
IPC codes: D21H27, D21H21, A24D1, D21H17