CIGAR SMOKE FILTER AND METHOD FOR IMPROVING THE QUALITY OF CIGAR SMOKE
United States Patent 3636957
Improving the taste and flavor of cigar smoke which involves using a filter employing an activated carbon filter material having a high-adsorptive capacity for the volatile organic components of cigar smoke and particularly between about 0.04 and 0.17 weight parts per weight part of tobacco of activated carbon filter material having a pore volume of at least about 0.3 cm.3 /gm. in the pore diameter range from about 10 to 40 angstrom units and containing between about 8 percent and 35 percent by weight of adsorbed moisture.
US Patent References:
Filter cigarette
Barnett - January 1961 - 2968305
Tobacco smoke filter element
Irby et al. - February 1966 - 3236244
Tobacco smoke filter
Keith et al. - May 1966 - 3251365
Cigarette and smoke filter and flavor means
Karalus - September 1967 - 3339557
Method of producing a filter element
Sublett et al. - April 1968 - 3381070
Filter cigarette
Barnett - January 1961 - 2968305
Tobacco smoke filter element
Irby et al. - February 1966 - 3236244
Tobacco smoke filter
Keith et al. - May 1966 - 3251365
Cigarette and smoke filter and flavor means
Karalus - September 1967 - 3339557
Method of producing a filter element
Sublett et al. - April 1968 - 3381070
Application Number:
05/121521
Publication Date:
01/25/1972
Filing Date:
03/05/1971
View Patent Images:
Export Citation:
Primary Class:
International Classes:
A24D3/16; A24D3/00; A24B15/02
Field of Search:
131/10,10.1,261-269
US Patent References:
| 3390686 | Tobacco smoke filter element | July 1968 | Irby et al. |
Other References:
Witco Chemical Co., N.Y.C., Abstracts (publication) Activated Carbon Abstracts, article entitled "Adsorption Processes" by J. W. Carter, p. 14, Spring 1967..
Primary Examiner:
Rein, Melvin D.
Parent Case Data:
This application is a continuation-in-part of application Ser. No. 728,314, filed May 10, 1968 now abandoned.
Claims:
I claim
1. In combination with a cigar, a filter section attached to one end of said cigar, said filter section comprising an activated carbon filter material having a pore volume of at least about 0.25 cm.3 per gram in the pore diameter range of from about 10 to 40 A., the weight ratio of the activated carbon in the filter ranging between 0.04 and 0.17 parts of activated carbon per weight part of tobacco, the activated carbon in said filter section containing between 8 percent and 35 percent of adsorbed moisture.
2. The method of improving the taste and flavor of cigar smoke which comprises conducting the cigar smoke from a burning cigar through a filter section, said filter section comprising an activated carbon filter material having a pore volume of at least about 0.25 cm.3 per gram in the pore diameter range of from about 10 to 40 A., the weight ratio of the activated carbon in the filter ranging between 0.04 and 0.17 parts of activated carbon per weight part of tobacco, the activated carbon in said filter section containing between 8 percent and 35 percent of adsorbed moisture.
1. In combination with a cigar, a filter section attached to one end of said cigar, said filter section comprising an activated carbon filter material having a pore volume of at least about 0.25 cm.3 per gram in the pore diameter range of from about 10 to 40 A., the weight ratio of the activated carbon in the filter ranging between 0.04 and 0.17 parts of activated carbon per weight part of tobacco, the activated carbon in said filter section containing between 8 percent and 35 percent of adsorbed moisture.
2. The method of improving the taste and flavor of cigar smoke which comprises conducting the cigar smoke from a burning cigar through a filter section, said filter section comprising an activated carbon filter material having a pore volume of at least about 0.25 cm.3 per gram in the pore diameter range of from about 10 to 40 A., the weight ratio of the activated carbon in the filter ranging between 0.04 and 0.17 parts of activated carbon per weight part of tobacco, the activated carbon in said filter section containing between 8 percent and 35 percent of adsorbed moisture.
Description:
This invention relates to the filtering of tobacco smoke and more particularly to certain activated-carbon filtering materials for removing undesirable volatile organic constituents from cigar tobacco smoke and the like to improve the flavor of the smoke, and to afford a means of introducing moisture into the smoking article and the smoke.
It has long been recognized that activated carbon has a certain utility as a filter material for tobacco smoke, being nontoxic and inexpensive and having a high absorptive capacity for the noxious elements of tobacco smoke. Various tobacco filter elements using activated carbon and other materials have been proposed as disclosed, for instance, in U.S. Pat. Nos. 1,985,840; 2,792,006; 2,933,420; 2,988,088; 3,054,410; 3,236,244; 3,251,365, and 3,319,629. Such filters and filter materials, generally speaking, are concerned chiefly with the elimination of tar and other undesirable materials from tobacco smoke. It has been noted in U.S. Pat. Nos. 1,985,840 and 3,251,365, however, that when highly adsorbing materials such as activated carbon are incorporated in a tobacco smoke filter in sufficient quantities to reduce significantly the levels of undesirable smoke constituents, the taste and flavor of the smoke are adversely affected. Hence, a careful balance has had to be attained between maximum removal of harmful materials and minimum alteration of taste.
In accordance with the present invention, I have discovered that the taste and flavor of cigar smoke can be substantially improved by using filtering material for said tobacco smoke comprising certain activated carbons hereinafter described. The said filtering materials not only remove undesirable constituents from tobacco smoke but also afford a means for introducing advantageous quantities of moisture into the smoke and the smoking article.
It is known that activated carbons differ markedly in various of their adsorption characteristics, these differences being not only dependent upon the physical form of the carbon, but, even more so, on the method of manufacturing and the source and type of raw material from which the activated carbon is prepared.
The report of the Advisory Committee to the Surgeon General of the U.S. Public Health Service, "Smoking and Health," Public Health Service Publication No. 1103, advises on p. 61 that "activated carbons differ markedly in their adsorption characteristics. Carbon filters previously employed in cigarettes do not have the specific power to scrub the gas phase." While most varieties of activated carbon will adsorb certain constituents found in tobacco smoke, it has been found, pursuant to the present invention, that optimum adsorption of the volatile organic components of the smoke is realized by the use of only certain activated carbons which have the pore size distribution requisite to efficient adsorption over the entire spectrum of the many molecular configurations in the smoke.
Activated carbon is a complex network of pores of varied shapes and sizes, the pore sizes ranging from diameters of less than 10 A. to over 100,000 A. The pore size distributions will depend to a great extent on the raw material source and on the method and extent of activation. The power of activated carbon to adsorb the volatile organic components, i.e., "gas or vapor phase," and/or the nongaseous "liquid phase" constituents of cigar smoke is definitely related to the pore volume and the pore diameter distribution within the carbon.
A typical analysis of the pore diameter and pore volume distribution of activated carbon samples derived from petroleum base and lignite base raw materials is summarized in table 1 and points out the variations that can be generally expected between gas phase and liquid phase carbons.
TABLE 1
Pore Volume Distribution
Gas phase carbon Liquid phase carbon Pore diameter Petroleum base Lignite base Angstroms (A.) Volume (cm. 3 /g.) Volume (cm. 3 /g.) ____________________________________________________________ ______________ 100,000-10,000 0.042 0.071 10,000-1,000 0.012 0.121 1,000-200 0.012 0.104 200-40 0.015 0.145 40-10 0.380 0.190 10-0 0.084 0.050 ____________________________________________________________ ______________
The activated carbons suitable for use in accordance with the practice of the present invention are those carbons having a pore volume of at least about 0.25 cm. 3 /g. and preferably at least about 0.3 cm. 3 /g. in the pore diameter range of between about 10 A. and 40 A. Such activated carbons have been found to exhibit an unusually high adsorptive capacity for those volatile components of cigar smoke which impart an unpleasant taste or flavor to cigar smoke, and, thus, are most advantageously employed as a filter material for improvement of the taste and flavor of cigar smoke. Petroleum-based materials are generally the most desirable source for said activated carbons, which can be prepared by any one of various known procedures.
Activated carbons suitable for use in accordance with the present invention generally contain small amounts of adsorbed moisture as a result of normal contact with the atmosphere. However, it has been discovered, further, that it is particularly advantageous to humidify the activated carbon to the extent that said carbon contains from about 8 percent to about 35 percent by weight and, better yet, between about 20 percent and 30 percent by weight of adsorbed moisture based on the weight of the activated carbon. Activated carbon which has been so humidified not only has been found to remove certain objectionable volatile organic constituents from cigar smoke effectively, thereby improving its flavor and taste, but, further, the taste is improved by said addition of moisture. Still another advantage derived from the humidification of the activated carbon pursuant to the present invention is the maintenance of freshness and softness of the smoking article for extended periods when the humidified activated-carbon filter material is packaged as an integral part of the smoking article.
Illustrative of the effectiveness of the activated carbon cigar smoke filter material of the present invention in removing volatile organic constituents from cigar tobacco smoke are the results summarized in table II obtained from a laboratory "smoking machine."
TABLE II
wt. of tobacco Puffs* Wt. of carbon in smoking 5-13 14-22 23-30 Avg. in filter (g.) Article (g.) Total Organic Volatiles %** ____________________________________________________________ ______________ 0 3.5 1.9 2.0 2.2 2.0 1.7 1.7 1.9 1.8 0.4 3.5 0.9 1.1 1.3 1.1 0.7 0.9 ____________________________________________________________ ______________ *A puff taken every minute; alternate puffs measured. **Total organic volatiles expressed as equivalent % methane.
The activated carbon employed in the above evaluation was produced from petroleum-based raw materials and had a pore volume of 0.380 cm. 3 /g. in the pore diameter range of 10 A. to 40 A. It is available commercially as WITCO GRADE 637.
Smoker Test Panel evaluation of smoking articles using the combination of activated carbon, cigar tobacco and weight proportions described in table II, which combination removes about 50 percent of the volatile organic material from the cigar smoke, determined that a mild, pleasant smoke was obtained of improved quality over that of the unfiltered cigar.
It has been found advantageous to employ activated carbon as hereinabove described as a filter material for cigar smoke in accordance with the practice of the present invention in amounts ranging between about 0.04 and 0.17 and preferably between about 0.1 and 0.15 weight parts of carbon per weight part of cigar tobacco. Cigar filters utilizing activated carbon in accordance with the present invention may be prepared in various ways well known in the art. The filter, for example, may be prepared from very finely divided carbon combined with cellulose acetate to form a filter plug, or coarse granules of carbon may be retained in a filter tip between two wads of cellulose acetate, cotton and the like, or incorporated in one end of a cigar by rolling the tobacco leaf around it during the cigar manufacture.
Evaluation of the taste and flavor of cigar smoke by a taste panel of five members experienced in the art of describing and evaluating the taste and aroma of tobacco smoke was carried out generally according to the description in Perfumery and Essential Oil Record, 49,130 (1958) and in an article by E. I. Salzman in Bulletin Corseta, No. 1961-1. Each member of the panel evaluated the desirable, i.e., sweet fragrance and smoothness, and undesirable taste elements, i.e., bitter taste and irritation, on a scale of 1 to 5 where 1 indicates the taste and flavor of unfiltered smoke and 5 indicates substantial improvement in taste and flavor. The average of the numerical ratings by the panel members is calculated and recorded as the Taste Panel Rating. The panel also evaluated the draw resistance for each sample since this is another significant factor in smoker enjoyment and acceptance, and recorded their determination as satisfactory (S) or unsatisfactory (U).
The following examples are given by way of illustration and not of limitation.
Two styles of cigars available to the public were used in this example. One style weighed 9 grams and is hereinafter called H, the other style weighed 3.5 grams and is hereinafter called L. A plastic cigar holder capable of holding each size of cigar was used as a retainer for the activated carbon filter material.
The following samples were prepared:
1.H: A 9-gram cigar inserted in cigar holder without any filter material.
1L: A 3.5-gram cigar inserted in cigar holder without any filter material.
2H: A 9-gram cigar inserted in cigar holder containing 1.25 grams of activated carbon which consisted of 1 gram of activated carbon and 0.25 gram of adsorbed moisture. The activated carbon used in this sample had a pore volume of 0.380 cm. 3 /g. in the pore diameter range of 10 to 40 A. and is available under the Trade Name WITCO GRADE 637.
2l: a 3.5-gram cigar inserted in a cigar holder containing 0.5 gram of activated carbon which consisted of 0.4 gram of carbon and 0.1 gram of adsorbed moisture. The activated carbon used in sample 2H was used in this sample.
3H: A 9-gram cigar inserted in cigar holder containing 2.5 grams of the activated carbon which consisted of 2 grams of the activated carbon of sample 2H and 0.5 gram of adsorbed moisture.
4H: A 9-gram cigar inserted in cigar holder containing 0.6 gram of activated carbon consisting of 0.5 gram of the activated carbon of sample 2H and 0.1 gram of adsorbed moisture.
5H: A 9-gram cigar inserted in cigar holder containing 1.25 grams of activated carbon consisting of 1 gram of activated carbon have a pore volume of 0.190 cm. 3 /g. in the pore diameter range of 10 to 40 A. and 0.25 gram of adsorbed moisture.
6H: A 9-gram cigar inserted in cigar holder containing 2.5 grams of activated carbon consisting of 2 grams of the activated carbon of Sample 5H and 0.5 gram of adsorbed moisture.
7H: A 9-gram cigar inserted in cigar holder containing 1 gram of the dry-activated carbon of sample 2H.
Results of the taste panel evaluation of the samples of this example are given in table III.
table iii
sample 1H 1L 2H 2L 3H 4H 5H 6H 7H Smoke quality 1 1 5 5 3 3 2 2 4 Draw Resistance S S S S U S S U S ____________________________________________________________ ______________
the filter material of the present invention, a "gas-phase" activated carbon, is markedly superior to the "liquid phase" type of activated carbon for improving the taste and flavor of cigar smoke and such improvement can be realized without adversely affecting the draw resistance of the cigars.
Although various embodiments have been described in the foregoing discussion and experiments for purpose of illustration, many modifications will occur to those skilled in the art and can be made without departing from the scope of this invention except as is limited in the appended claims.
It has long been recognized that activated carbon has a certain utility as a filter material for tobacco smoke, being nontoxic and inexpensive and having a high absorptive capacity for the noxious elements of tobacco smoke. Various tobacco filter elements using activated carbon and other materials have been proposed as disclosed, for instance, in U.S. Pat. Nos. 1,985,840; 2,792,006; 2,933,420; 2,988,088; 3,054,410; 3,236,244; 3,251,365, and 3,319,629. Such filters and filter materials, generally speaking, are concerned chiefly with the elimination of tar and other undesirable materials from tobacco smoke. It has been noted in U.S. Pat. Nos. 1,985,840 and 3,251,365, however, that when highly adsorbing materials such as activated carbon are incorporated in a tobacco smoke filter in sufficient quantities to reduce significantly the levels of undesirable smoke constituents, the taste and flavor of the smoke are adversely affected. Hence, a careful balance has had to be attained between maximum removal of harmful materials and minimum alteration of taste.
In accordance with the present invention, I have discovered that the taste and flavor of cigar smoke can be substantially improved by using filtering material for said tobacco smoke comprising certain activated carbons hereinafter described. The said filtering materials not only remove undesirable constituents from tobacco smoke but also afford a means for introducing advantageous quantities of moisture into the smoke and the smoking article.
It is known that activated carbons differ markedly in various of their adsorption characteristics, these differences being not only dependent upon the physical form of the carbon, but, even more so, on the method of manufacturing and the source and type of raw material from which the activated carbon is prepared.
The report of the Advisory Committee to the Surgeon General of the U.S. Public Health Service, "Smoking and Health," Public Health Service Publication No. 1103, advises on p. 61 that "activated carbons differ markedly in their adsorption characteristics. Carbon filters previously employed in cigarettes do not have the specific power to scrub the gas phase." While most varieties of activated carbon will adsorb certain constituents found in tobacco smoke, it has been found, pursuant to the present invention, that optimum adsorption of the volatile organic components of the smoke is realized by the use of only certain activated carbons which have the pore size distribution requisite to efficient adsorption over the entire spectrum of the many molecular configurations in the smoke.
Activated carbon is a complex network of pores of varied shapes and sizes, the pore sizes ranging from diameters of less than 10 A. to over 100,000 A. The pore size distributions will depend to a great extent on the raw material source and on the method and extent of activation. The power of activated carbon to adsorb the volatile organic components, i.e., "gas or vapor phase," and/or the nongaseous "liquid phase" constituents of cigar smoke is definitely related to the pore volume and the pore diameter distribution within the carbon.
A typical analysis of the pore diameter and pore volume distribution of activated carbon samples derived from petroleum base and lignite base raw materials is summarized in table 1 and points out the variations that can be generally expected between gas phase and liquid phase carbons.
TABLE 1
Pore Volume Distribution
Gas phase carbon Liquid phase carbon Pore diameter Petroleum base Lignite base Angstroms (A.) Volume (cm. 3 /g.) Volume (cm. 3 /g.) ____________________________________________________________ ______________ 100,000-10,000 0.042 0.071 10,000-1,000 0.012 0.121 1,000-200 0.012 0.104 200-40 0.015 0.145 40-10 0.380 0.190 10-0 0.084 0.050 ____________________________________________________________ ______________
The activated carbons suitable for use in accordance with the practice of the present invention are those carbons having a pore volume of at least about 0.25 cm. 3 /g. and preferably at least about 0.3 cm. 3 /g. in the pore diameter range of between about 10 A. and 40 A. Such activated carbons have been found to exhibit an unusually high adsorptive capacity for those volatile components of cigar smoke which impart an unpleasant taste or flavor to cigar smoke, and, thus, are most advantageously employed as a filter material for improvement of the taste and flavor of cigar smoke. Petroleum-based materials are generally the most desirable source for said activated carbons, which can be prepared by any one of various known procedures.
Activated carbons suitable for use in accordance with the present invention generally contain small amounts of adsorbed moisture as a result of normal contact with the atmosphere. However, it has been discovered, further, that it is particularly advantageous to humidify the activated carbon to the extent that said carbon contains from about 8 percent to about 35 percent by weight and, better yet, between about 20 percent and 30 percent by weight of adsorbed moisture based on the weight of the activated carbon. Activated carbon which has been so humidified not only has been found to remove certain objectionable volatile organic constituents from cigar smoke effectively, thereby improving its flavor and taste, but, further, the taste is improved by said addition of moisture. Still another advantage derived from the humidification of the activated carbon pursuant to the present invention is the maintenance of freshness and softness of the smoking article for extended periods when the humidified activated-carbon filter material is packaged as an integral part of the smoking article.
Illustrative of the effectiveness of the activated carbon cigar smoke filter material of the present invention in removing volatile organic constituents from cigar tobacco smoke are the results summarized in table II obtained from a laboratory "smoking machine."
TABLE II
wt. of tobacco Puffs* Wt. of carbon in smoking 5-13 14-22 23-30 Avg. in filter (g.) Article (g.) Total Organic Volatiles %** ____________________________________________________________ ______________ 0 3.5 1.9 2.0 2.2 2.0 1.7 1.7 1.9 1.8 0.4 3.5 0.9 1.1 1.3 1.1 0.7 0.9 ____________________________________________________________ ______________ *A puff taken every minute; alternate puffs measured. **Total organic volatiles expressed as equivalent % methane.
The activated carbon employed in the above evaluation was produced from petroleum-based raw materials and had a pore volume of 0.380 cm. 3 /g. in the pore diameter range of 10 A. to 40 A. It is available commercially as WITCO GRADE 637.
Smoker Test Panel evaluation of smoking articles using the combination of activated carbon, cigar tobacco and weight proportions described in table II, which combination removes about 50 percent of the volatile organic material from the cigar smoke, determined that a mild, pleasant smoke was obtained of improved quality over that of the unfiltered cigar.
It has been found advantageous to employ activated carbon as hereinabove described as a filter material for cigar smoke in accordance with the practice of the present invention in amounts ranging between about 0.04 and 0.17 and preferably between about 0.1 and 0.15 weight parts of carbon per weight part of cigar tobacco. Cigar filters utilizing activated carbon in accordance with the present invention may be prepared in various ways well known in the art. The filter, for example, may be prepared from very finely divided carbon combined with cellulose acetate to form a filter plug, or coarse granules of carbon may be retained in a filter tip between two wads of cellulose acetate, cotton and the like, or incorporated in one end of a cigar by rolling the tobacco leaf around it during the cigar manufacture.
Evaluation of the taste and flavor of cigar smoke by a taste panel of five members experienced in the art of describing and evaluating the taste and aroma of tobacco smoke was carried out generally according to the description in Perfumery and Essential Oil Record, 49,130 (1958) and in an article by E. I. Salzman in Bulletin Corseta, No. 1961-1. Each member of the panel evaluated the desirable, i.e., sweet fragrance and smoothness, and undesirable taste elements, i.e., bitter taste and irritation, on a scale of 1 to 5 where 1 indicates the taste and flavor of unfiltered smoke and 5 indicates substantial improvement in taste and flavor. The average of the numerical ratings by the panel members is calculated and recorded as the Taste Panel Rating. The panel also evaluated the draw resistance for each sample since this is another significant factor in smoker enjoyment and acceptance, and recorded their determination as satisfactory (S) or unsatisfactory (U).
The following examples are given by way of illustration and not of limitation.
Two styles of cigars available to the public were used in this example. One style weighed 9 grams and is hereinafter called H, the other style weighed 3.5 grams and is hereinafter called L. A plastic cigar holder capable of holding each size of cigar was used as a retainer for the activated carbon filter material.
The following samples were prepared:
1.H: A 9-gram cigar inserted in cigar holder without any filter material.
1L: A 3.5-gram cigar inserted in cigar holder without any filter material.
2H: A 9-gram cigar inserted in cigar holder containing 1.25 grams of activated carbon which consisted of 1 gram of activated carbon and 0.25 gram of adsorbed moisture. The activated carbon used in this sample had a pore volume of 0.380 cm. 3 /g. in the pore diameter range of 10 to 40 A. and is available under the Trade Name WITCO GRADE 637.
2l: a 3.5-gram cigar inserted in a cigar holder containing 0.5 gram of activated carbon which consisted of 0.4 gram of carbon and 0.1 gram of adsorbed moisture. The activated carbon used in sample 2H was used in this sample.
3H: A 9-gram cigar inserted in cigar holder containing 2.5 grams of the activated carbon which consisted of 2 grams of the activated carbon of sample 2H and 0.5 gram of adsorbed moisture.
4H: A 9-gram cigar inserted in cigar holder containing 0.6 gram of activated carbon consisting of 0.5 gram of the activated carbon of sample 2H and 0.1 gram of adsorbed moisture.
5H: A 9-gram cigar inserted in cigar holder containing 1.25 grams of activated carbon consisting of 1 gram of activated carbon have a pore volume of 0.190 cm. 3 /g. in the pore diameter range of 10 to 40 A. and 0.25 gram of adsorbed moisture.
6H: A 9-gram cigar inserted in cigar holder containing 2.5 grams of activated carbon consisting of 2 grams of the activated carbon of Sample 5H and 0.5 gram of adsorbed moisture.
7H: A 9-gram cigar inserted in cigar holder containing 1 gram of the dry-activated carbon of sample 2H.
Results of the taste panel evaluation of the samples of this example are given in table III.
table iii
sample 1H 1L 2H 2L 3H 4H 5H 6H 7H Smoke quality 1 1 5 5 3 3 2 2 4 Draw Resistance S S S S U S S U S ____________________________________________________________ ______________
the filter material of the present invention, a "gas-phase" activated carbon, is markedly superior to the "liquid phase" type of activated carbon for improving the taste and flavor of cigar smoke and such improvement can be realized without adversely affecting the draw resistance of the cigars.
Although various embodiments have been described in the foregoing discussion and experiments for purpose of illustration, many modifications will occur to those skilled in the art and can be made without departing from the scope of this invention except as is limited in the appended claims.