RS54104B1 - ACTIVE COAL CIGARETTE ON ACETATE FILTER FIBERS - Google Patents

Abstract

Cigarette (10, 10A, 10B, 10C) consisting of a cigarette stick (12) and activated carbon filters on acetate fibers (14) made of acetate fibers (18, 18A) with carbon particles (20, 20A) arranged between the fibers , the acetate fiber activated carbon filter is designed and installed to significantly reduce at least one smoke component from the mainstream of tobacco smoke when it is drawn through the filter and the carbon particles have an activity in the range of 90% to 115%, as measured by CTC (carbon tetrachloride) methodology, characterized in that the filter comprises ventilation positioned at least 12 mm from the lip end of the cigarette. The application contains 8 more claims.

Description

[0001] Field of the subject invention

[0002] The present invention relates to tobacco products such as cigarettes, especially to cigarettes containing filtering parts consisting of adsorbent and fibrous filtering material placed so as to improve the removal of gas phase components from the main stream of tobacco smoke during prolonged storage of the cigarette.

[0003] State of the art

[0004] Tobacco products, especially cigarettes, usually consist of a cigarette stick made of a tobacco filling (roll) of cut tobacco (usually in the form of a filling) covered with a paper wrapper and a cylindrical filter placed in line with the cigarette stick so that their ends touch. Typically the filter includes a filter insert ("plug") of non-spun fibers of acetylated cellulose (hereafter referred to as acetate fibers) attached to the cigarette stick by means of filter paper. Ventilation of the main stream of tobacco smoke is achieved by means of a row or rows of holes (hereinafter referred to as perforations) placed around the place located along the filter. Such ventilation ensures the dilution of the main stream of tobacco smoke drawn in by the surrounding air in order to reduce the delivery of "tar" (in English: tobacco residue; the dry residue of tobacco smoke without nicotine, hereinafter referred to as tar).

[0005] After lighting a cigarette, the smoker draws the main stream of tobacco smoke from the embers at the lit end of the cigarette. The inhaled cigarette smoke first enters the upper part of the filter and then passes through the lower part next to the buccal (oral) end of the cigarette.

[0006] Some cigarettes have filters incorporating adsorbent materials such as activated carbon (hereafter activated carbon) and examples of these are described in U.S. Patent Applications. Pat. numbers 2,881,770 by Tovey; 3,353,543 to Sproull et al.; 3,101,723 to Seligman et al; and 4,481,958 to Ranier et al. Some commercially available filters have only particles or granules of carbon (that is, activated carbon material) or they are dispersed within the acetate fibers; other commercially available filters have carbon fibers embedded in them; while other commercially available filters are designed as so-called "plug-space-plug", "cavitv filter" or "triple filter" filters. Examples of commercially available filters are the SCS IV Dual Solid Charcoal Filter and the Triple Solid Charcoal Filter Charcoal Filter) manufactured by Filtrona International, Ltd.; triple cavity filter (Triple Cavity Filter) manufactured by Baumgartner and ACT manufactured by Filtrona International, Ltd. See also Clarke et al., World Tobacco, p. 55 (November 1992). A detailed discussion of the properties and composition of cigarettes and filters can be found in U.S. Pat. Pat. Nos. 5,404,890 and 5,568,819 to Gentrv et al., the disclosure of which is incorporated herein by reference.

[0007] Typical of prior practice with "cap-void-cap" designed cigarettes was that the vent was positioned along the layer of adsorbent contained in the void so as to achieve a sufficient distance of the vents from the mouth end of the filter. That way the smoker's lips would not block the vents. However, such placement tends to reduce the adsorbent's filtering effectiveness because it tends to increase the flow rate of the tobacco mainstream. smoke in at least one part of the adsorbent layer.

[0008] Various annular filter configurations with circular portions containing activated carbon filter areas have been described in the art. For example, European Patent Application No. 579,410 provides several embodiments of cigarettes having an annular region of activated carbon surrounding either a porous filter material or an empty tubular cavity formed by a gas permeable membrane. Similarly, the U.S. Pat. No. 3,894,545 to Crellin et al. provides various configurations of annular activated carbon regions surrounding a gas permeable membrane or rods of activated carbon material surrounded by a gas permeable membrane.

[0009] The parts of cigarette filters that contain carbon in them have the ability to remove the constituents of the main stream of tobacco smoke that passes through them. In particular, activated carbon has a tendency to reduce the levels of some gaseous constituents present in mainstream tobacco smoke, leading to changes in the organoleptic properties of that smoke.

[0010] Despite these advantages of activated carbon filters, they have not been widely used to date. In previous settings, it was discovered that mainstream tobacco smoke from carbon filters tends to take on a flavor that is contrary to consumer preferences and that their use in commercially offered cigarettes has not been widespread until now. Also, plasticizers in acetate filter fibers tend to degrade some carbon components over time and thereby reduce its effectiveness in removing gaseous constituents during prolonged storage of cigarettes containing such arranged filters.

[0011] It would be desirable to provide a cigarette that has a filter with activated carbon and/or other materials capable of absorbing and/or adsorbing gas constituents present in the main stream of cigarette tobacco smoke and at the same time has favorable characteristics of absorption/adsorption, dilution and withdrawal of smoke.

[0012] Additionally, it would be desirable to provide such a filter that has the desired smoke retention time in the area containing the adsorbent/absorbent while simultaneously achieving a pressure drop behind the area. dilution and adsorption/absorption so that it provides acceptable smoke draw characteristics with reduced gas constituents along with acceptable taste and drag resistance.

[0013] Brief description of the subject invention

[0014] According to the present invention, a tobacco product such as a cigarette consists of a cigarette stick and a multicomponent filter that contains acetate fibers with highly active carbon particles on them. In a preferred embodiment, the activated carbon is simultaneously the carrier of the aroma and contains highly active carbon particles on the acetate fibers of the filter. As the main stream of tobacco smoke is drawn through the upper part of the filter, the gaseous constituents of the smoke are removed and the aroma is released from the activated carbon. Ventilation is provided to limit the amount of tobacco burned during each draw and such ventilation is located behind the activated carbon area on the acetate fibers to reduce the flow rate of the mainstream tobacco smoke through the adsorbent. HQPs on acetate fibers are believed to provide significant reductions in mainstream gaseous constituents of tobacco smoke, including 90% or greater reductions in 1,3-butadiene, acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, and toluene, and 80% or greater reductions in acetaldehyde.

[0015] The advantage of the present invention is that it deals with the problem of the desirability of achieving the optimal residence time of smoke in the area of the filter with the adsorption material while simultaneously achieving the desired dilution of the smoke with the surrounding air and causing an acceptable resistance to smoke withdrawal as expected by most smokers.

[0016] With the foregoing and other advantages and features of the subject invention which will later become apparent herein, the nature of the subject invention may be more clearly understood by reviewing the following detailed description of the subject invention, the appended claims and several illustrations provided in the drawings.

[0017] Brief description of the drawings

[0018] New features and advantages of the subject invention in addition to those previously mentioned will be apparent to one of ordinary skill in the art by reading the following detailed description in conjunction with the accompanying drawings in which like reference numerals refer to like parts and in which: Figure 1 is a side view of a cigarette in accordance with the subject invention consisting of a cigarette stick and a multicomponent filter containing particles of highly activated carbon on acetate fibers, parts of which have been removed to internal details would be displayed;

[0019] Fig. 2 is a side view of another cigarette according to the present invention consisting of a tobacco stick and a multicomponent filter containing particles of highly active carbon on acetate fibers, parts of which have been removed to show internal details;

[0020] Fig. 3 is a side view of another cigarette according to the present invention consisting of a cigarette stick and a multi-component filter containing particles of highly activated carbon, with the addition of aroma behind, on acetate fibers, parts of which have been removed to show internal details; and

[0021] Fig. 4 is a side view of another cigarette according to the present invention consisting of a cigarette stick and a multicomponent filter containing particles of highly activated carbon, with the addition of aroma behind, on acetate fibers, parts of which have been removed to show internal details.

[0022] Detailed description of the subject invention

[0023] With regard to Figure 1, a preferred embodiment of the present invention provides a cigarette 10 consisting of a cigarette stick 12, which contains a smoking material such as cut tobacco, and a multicomponent filter 14 attached to the stick 12 by means of a filter paper 16. After lighting the cigarette 10, the main stream of tobacco smoke is created by pulling from the cigarette stick 12 and passing it through the filter. 14.

[0024] Here, the relative positions "in front" and "behind" between the filter parts and the other parts are described in relation to the direction of flow of the main stream of tobacco smoke as it is withdrawn from the cigarette stick 12 and through the multicomponent filter 14.

[0025] Preferably, the filter 14 comprises acetate fibers 18 containing a suitable plasticizer such as triacetin with highly active activated carbon particles in the form of granules 20 distributed throughout the acetate fibers. The mouth end (the part that goes into the mouth) 22 is the part that is located after the acetate fibers 18 and the carbon particles 20.

[0026] Mouth piece 22 is preferably in the form of cellulose, acetate plug or other suitable fibrous or mesh material with medium to low particle efficiency. Preferably, the fineness, in dens and total dens, is selected so that the particle efficiency is low so that the desired total RTD of the multicomponent filter 14 is achieved.

[0027] The carbon particles 20 on the acetate fibers 18 are preferably in the form of granules and the like. Preferably, the carbon in the preferred embodiment is a highly activated carbon with a high surface area, for example a coconut shell-based carbon with a typical or finer ASTM mesh size used in the tobacco industry. Activated carbon adsorbs mainstream tobacco smoke constituents, particularly those from the gas phase including aldehydes, ketones and other volatile organic compounds, particularly 1,3 butadiene, acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, toluene, styrene, acetaldehyde and hydrogen cyanide.

[0028] As for the carbon particles 20, it is preferable that they have a mesh size of 10 to 80, and even more preferably the mesh size is from 20 to 70. In addition, as previously mentioned,

[0029] The carbon particles are highly active, with total activity ranging from 90% to 115% with a target activity of around 95%, as measured using the CTC (carbon tetrachloride) methodology.

[0030] Carbon particles 20 may carry aroma or otherwise be impregnated with aroma so that these adsorbing particles not only remove one or more gaseous constituents of smoke from the tobacco smoke mainstream but also release the aroma into the tobacco smoke mainstream. Preferably, the flavoring is added to the carbon granules by spraying over the activated carbon in the mixing drum or alternatively by spraying the flavoring over the fluidized bed created by blowing nitrogen as a fluidizing agent. The addition of flavoring is done before the distribution of the carbon granules throughout the acetate fibers 18.

[0031] One or more annular rows of perforations 24 are made through the filter paper 16 at a location along the lower portion of the area with carbon particles on the acetate fibers 18, 20. The preferred location maximizes the distance between the mouth end of the cigarette and the perforations 24, which is at least 12 mm (millimeters) or more, so that the smoker's lips do not close the perforations 24.

[0032] Preferably, the level of ventilation is in the range of 40% to 60% and more preferably approximately 45% to 55% for a cigarette containing 6 mg of FTC tar.

[0033] It is believed that the ventilation paired with the low-efficiency particulate filter 14 not only allows for the dilution of the main stream of tobacco smoke but also has the effect of reducing the amount of tobacco burned with each puff of smoke. Ventilation reduces the force of the pull over the coal and thus reduces the amount of tobacco that burns with each puff of smoke. The result is a decrease in the absolute amounts of smoke components.

[0034] The advantage is that the perforations 24 of the present invention are placed on the lower part of the filter area with activated carbon on the acetate fibers so that the flow rate of the main stream of tobacco smoke through most of the carbon particles 20 is reduced and thus the residence time of the main stream of smoke between the carbon particles 20 is prolonged. The smoke is diluted by ambient air passing through the perforations 24 and mixed with the main stream of smoke to achieve a dilution in the range of approximately 45% to 65%. For example, with an air dilution of 50%, the flow through the cigarette in front of the perforations is reduced by 50%, thereby reducing the smoke velocity by 50%.

[0035] Preferably, the loading range of the carbon particles 20 on the acetate fibers 18 consists of at least 90 to more than 120 mg (milligrams) with a target loading of approximately 120 mg. Such carbon filling provides a full-flavored cigarette while simultaneously achieving a reduction in the amount of gaseous constituents of the mainstream tobacco smoke, including a reduction of 90% or greater in the case of 1,3 butadiene, acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, toluene, and a reduction of 80% or greater in the case of acetaldehyde. Increased carbon loading as well ensures an adequate level of activity sufficient to achieve such reductions during the expected storage period of the product (up to six months or longer).

[0036] With a carbon activity in the range of 90% to 110% and a target activity of approximately 95%, there is no significant adverse effect of the plasticizer (triacetin, for example) used on the acetate fibers 18. When the filter acetate fibers 18 are acetylated cellulose with triacetin as a plasticizer, the level of triacetin can be whatever is needed (typically about 6%) and such a level does not adversely affect the previously given percentages of reduction of gaseous constituents of the main stream of tobacco smoke. With these percentages of carbon activity, there is no significant deactivation of carbon during the storage period of cigarettes, whereby percentages of reduction of gaseous components occur during the entire storage period. Cigarettes with an extended storage period of twelve months have almost the same effectiveness as cigarettes that are one month old.

[0037] As an example, the length of the cigarette stick 12 is preferably 49 mm, the length of the multicomponent filter 14 is preferably 34 mm. The length of the part with active carbon on the acetate fibers is preferably 20-26 mm, and the cellulose acetate plug 8 at the end of the filter 14 is preferably 8 mm. The total tar level (FTC) is preferably around 6 mg with a smoke draw number of 6 or more.

[0038] The cigarette stick 12 may be wrapped in a conventional cigarette wrapper or paper with strips may be used for this purpose. The banded cigarette paper has mutually spaced integral bands of cellulose 21 that wrap around the finished cigarette stick of the cigarette 10 to modify the amount of cigarette mass burned so as to reduce the risk of the substrate igniting if the cigarette 10 is left to smolder thereon. U.S. Patent Applications Patent Nos. 5,263,999 and 5,997,691 describe strip cigarette paper and their patents are incorporated herein in their entirety.

[0039] In the preferred embodiment 10 of Figure 1, 90 to 120 milligrams, preferably about 120 milligrams, of highly active aromatized carbon 20 is distributed throughout the acetate fibers 18. Optional aromatic substance loading is from 3 to 6 mg in the carbon particles 20, and more preferably approximately 4 or 5 mg. A loading of 6 mg of flavoring system per 120 mg of carbon was shown to have no detrimental effect on constituent removal. It should be understood that the reference to 120 mg of aromatized carbon loading herein includes any aromatic substance. Additionally, as previously noted, carbon activity ranges from 90% to 110% with a target activity of approximately 95%. Despite the plasticizer in the acetate fibers 18 in an amount of about 6%, the activated carbon filter components on the acetate fibers retain their effectiveness in removing gaseous constituents during extended storage of the cigarette 10.

[0040] Regarding the tables I-V below, the obtained data show the average percentages of reduction of certain gas components of the head stream of tobacco smoke obtained on the test cigarettes, as explained in the headers of each table, in relation to the commercially offered cigarette (control). For a given test cigarette, the first column of percentages gives the initial average reduction vs

[0041] control; and the second and third columns respectively give the average shrinkage of the test cigarettes after exposure to conditions simulating approximately six (6) months of storage and approximately twelve (12) months of storage. The accelerated aging process involves cyclically subjecting cigarettes to conditions of high and low humidity and high temperature for a prescribed period of time.

[0042] As the tables show, a significant reduction in the gaseous constituents of the smoke was achieved with 120 milligrams of carbon on acetate fibers, even in the presence of triacetin and even after a significant period of simulated storage corresponding to one year of natural aging.

[0043]

[0044] Fig. 2 shows a cigarette 10A with a shorter portion with acetate fibers 18A and a reduced charge of carbon particles 20A distributed between the acetate fibers. The carbon fill is about 75 milligrams and the carbon is unflavored. Carbon activity ranges from 90% to 115% with a target activity of 95%.

[0045] With respect to Figures 3 and 4, alternative preferred embodiments include cigarettes 10B, 10C that include an activated carbon filter plug on acetate fibers 18 whose carbon loading is approximately 75 to 120 milligrams or greater with increased activity levels (90% to 110% with a target level of approximately 95%), more preferably approximately 120 milligrams of such carbon per cigarette. 10B and approximately 75 milligrams of such carbon in cigarette 10C, both preferably unflavored. Approximately 90 mg of carbon is a desirable amount. In these embodiments, the filters further include aroma release elements 32, 32A located behind the carbon on the acetate fibers (in the sense of the direction in which the main stream of tobacco smoke is drawn through the cigarette), such as in Figure 3, a filter plug 32 containing fibers with an aromatic substance 33 (as described in commonly assigned patent application U.S. Patent No. 6,761,174) or a layer of aroma-releasing particles 35, as shown in Figure 4, which may be arranged in a plug-void-plug arrangement in element 32 or as a plug of acetate fibers with aromatic particles arranged thereon.

[0046] With increased carbon loading and increased carbon activity levels, these cigarettes 10B, 10C of Figures 3 and 4 offer improved off-gassing ability, acceptable shelf life and more desirable organoleptic properties.

[0047] In addition, the present invention can be applied to cigarettes of various sizes, thin cigarettes, as well as thick cigarettes. Although the present invention is preferably practiced with unflavored cigarette sticks, flavored tobacco material is also contemplated.

Claims (9)

1. A cigarette (10, 10A, 10B, 10C) comprising a cigarette stick (12) and an acetate fiber activated carbon filter (14) made of acetate fibers (18, 18A) with carbon particles (20, 20A) distributed between the fibers, the acetate fiber activated carbon filter being so constructed and positioned as to significantly reduce at least one smoke constituent from the main stream of tobacco smoke when it is pulled through the filter and the carbon particles have an activity ranging from 90% to 115%, measured using the CTC (carbon tetrachloride) methodology, indicated by the fact that the filter contains ventilation placed at least 12 mm from the mouth end of the cigarette. 2. A cigarette according to claim 1, characterized in that it contains carbon particles in an amount of 75 to 120 milligrams or more. 3. A cigarette according to claim 1 or 2, characterized in that it contains carbon particles in the amount of 120 milligrams. 4. A cigarette according to claim 1, 2 or 3 characterized in that the carbon particles are flavored. 5. A cigarette according to any of the preceding claims, characterized in that the activity of the carbon particles is 95%. 6. A cigarette according to any one of the preceding claims, characterized in that the filter includes ventilation in the range of 45% to 55%, and wherein the mouth end of the filter part (22) is placed behind the carbon on the acetate fibers. 7. Cigarette according to patent claim 6 characterized in that the ventilation contains at least one annular row of perforations (24) through the filter envelope (16), wherein the filter paper connects the filter with activated carbon on acetate fibers to the cigarette stick. 8. A cigarette according to any one of the preceding claims, characterized in that the acetate fibers contain a plasticizer. 9. A cigarette according to any of the preceding claims, characterized in that the filter includes a flavor release element (32, 32A) placed behind the carbon on the acetate fibers.