U.S. patent application number 15/338997 was filed with the patent office on 2017-02-16 for method of manufacturing smoking article with activated carbon sorbent and sodium bicarbonate-treated fibers.
The applicant listed for this patent is PHILIP MORRIS USA INC.. Invention is credited to Joel Schendel, Lixin Xue, Liqun Yu.
Application Number | 20170042220 15/338997 |
Document ID | / |
Family ID | 38163301 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170042220 |
Kind Code |
A1 |
Xue; Lixin ; et al. |
February 16, 2017 |
Method of Manufacturing Smoking Article With Activated Carbon
Sorbent and Sodium Bicarbonate-Treated Fibers
Abstract
Filters and smoking articles include sodium bicarbonate-treated
fibers and activated carbon capable of selectively removing one or
more selected constituents from mainstream smoke. Methods for
making cigarette filters and cigarettes using the sodium
bicarbonate-treated fibers and activated carbon, and methods for
treating mainstream smoke comprising the sodium bicarbonate-treated
fibers and activated carbon are also provided.
Inventors: |
Xue; Lixin; (Midlothian,
VA) ; Yu; Liqun; (Midlothian, VA) ; Schendel;
Joel; (Midlothian, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHILIP MORRIS USA INC. |
Richmond |
VA |
US |
|
|
Family ID: |
38163301 |
Appl. No.: |
15/338997 |
Filed: |
October 31, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11636588 |
Dec 11, 2006 |
9491971 |
|
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15338997 |
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60749595 |
Dec 13, 2005 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/048 20130101;
A24D 3/163 20130101; A24D 1/008 20130101; A24D 3/16 20130101; A24C
5/471 20130101; A24D 1/002 20130101; A24D 1/00 20130101; A24D 3/00
20130101; A24D 3/04 20130101 |
International
Class: |
A24D 3/04 20060101
A24D003/04; A24D 3/16 20060101 A24D003/16; A24D 1/00 20060101
A24D001/00; A24C 5/47 20060101 A24C005/47 |
Claims
1. A method of manufacturing a cigarette filter, comprising:
arranging activated carbon between a mouth end and an upstream end
of the cigarette filter; and arranging sodium bicarbonate-treated
fibers between the activated carbon and the mouth end.
2. The method of manufacturing the cigarette filter of claim 1,
wherein the sodium bicarbonate-treated fibers are of cellulose tow,
cellulose acetate tow, mono cellulose, mono acetate, propylene,
polyester, polysulfone or polypropylene.
3. The method of manufacturing the cigarette filter of claim 1,
wherein the filter contains from about 50 mg to about 250 mg of
activated carbon and the sodium bicarbonate-treated fibers contain
a total of from about 5 mg to about 100 mg of sodium
bicarbonate.
4. The method of manufacturing the cigarette filter of claim 1,
wherein the sodium bicarbonate-treated fibers contain about 5 mg to
about 30 mg of sodium bicarbonate.
5. The method of manufacturing the cigarette filter of claim 1,
wherein the sodium bicarbonate-treated fibers contain about 5 mg to
about 15 mg of sodium bicarbonate, the sodium bicarbonate-treated
fibers having been prepared by applying a solution containing
dissolved sodium bicarbonate to cellulose acetate tow fibers,
forming the treated fibers into a plug, and drying the plug.
6. The method of manufacturing the cigarette filter of claim 1,
wherein the activated carbon is in the form of fibers having a
length of from about 100 microns to about 1000 microns, and a
diameter of from about 10 microns to about 25 microns.
7. The method of manufacturing the cigarette filter of claim 6,
wherein the activated carbon is at least one monolithic body.
8. The method of manufacturing the cigarette filter of claim 1,
wherein the sodium bicarbonate-treated fibers are located adjacent
the activated carbon.
9. The method of manufacturing the cigarette filter of claim 1,
further comprising arranging a flavoring section between the sodium
bicarbonate-treated fibers and the mouth end, and/or between the
activated carbon and the sodium bicarbonate-treated fibers.
10. The method of manufacturing the cigarette filter of claim 1,
wherein the sodium bicarbonate-treated fibers are present in an
amount effective to remove at least a portion of at least one
sulfur-containing compound from mainstream smoke in the filter
during smoking of a tobacco rod attached to the cigarette
filter.
11. A method of manufacturing a cigarette, comprising: attaching a
tobacco column to a cigarette filter with tipping paper, the
cigarette filter comprising a mouth end, activated carbon, and
sodium bicarbonate-treated fibers located between the activated
carbon and the mouth end.
12. The method of manufacturing the cigarette of claim 11, wherein
the sodium bicarbonate-treated fibers are of cellulose tow,
cellulose acetate tow, mono cellulose, mono acetate, propylene,
polyester, polysulfone or polypropylene.
13. The method of manufacturing the cigarette of claim 11, wherein
the filter contains from about 50 mg to about 250 mg of activated
carbon and the sodium bicarbonate-treated fibers contain a total of
from about 5 mg to about 100 mg of sodium bicarbonate, the sodium
bicarbonate-treated fibers having been prepared by applying a
solution containing dissolved sodium bicarbonate to cellulose
acetate tow fibers, forming the treated fibers into a plug, and
drying the plug.
14. The method of manufacturing the cigarette of claim 11, wherein
the activated carbon is in the form of fibers having a length of
from about 100 microns to about 1000 microns, and a diameter of
from about 10 microns to about 25 microns.
15. The method of manufacturing the cigarette of claim 11, wherein
the activated carbon is at least one monolithic body or the sodium
bicarbonate-treated fibers are located adjacent the activated
carbon.
16. The method of manufacturing the cigarette of claim 11, further
comprising arranging a flavoring section between the sodium
bicarbonate-treated fibers and the mouth end of the filter and/or
between the activated carbon and the sodium bicarbonate-treated
fibers.
17. The method of manufacturing the cigarette of claim 11, wherein
the sodium bicarbonate-treated fibers are effective to remove at
least a portion of least one sulfur-containing compound in the
cigarette.
18. A method of manufacturing a cigarette, comprising: applying a
solution of dissolved sodium bicarbonate to fiber surfaces to form
treated fibers; forming the treated fibers into a discrete section
of sodium bicarbonate-treated fibers; arranging the discrete
section of sodium bicarbonate-treated fibers in a cigarette filter;
placing a paper wrapper around a tobacco column; and attaching the
cigarette filter to the tobacco column to form the cigarette.
19. The method of manufacturing the cigarette of claim 18, further
comprising arranging a discrete sorbent section comprising
activated carbon upstream of the discrete section of sodium
bicarbonate-treated fibers; and arranging a discrete flavoring
section downstream of the discrete sorbent section.
20. The method of manufacturing the cigarette of claim 18, wherein
the discrete sorbent section comprises carbon fibers.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of U.S.
patent application Ser. No. 11/636,588, filed Dec. 11, 2006 and
claims priority under 35 U.S.C. .sctn.119(e) to U.S. Provisional
Application No. 60/749,595, filed on Dec. 13, 2005 (now expired),
the entire contents of which are incorporated herein by
reference.
BACKGROUND
[0002] A variety of filter materials have been suggested for
incorporation into cigarette filters for treating tobacco smoke.
Such materials include, e.g., cellulose acetate cotton, paper and
synthetic fibers. Different forms of carbon have also been
described.
SUMMARY
[0003] Filters, smoking articles and methods for removing selected
constituents from mainstream smoke using activated carbon and
sodium bicarbonate are provided. A preferred embodiment of the
filters comprises activated carbon and sodium bicarbonate-treated
fibers, which can selectively remove constituents from mainstream
smoke. The activated carbon is provided upstream in the filter from
the sodium bicarbonate-treated fibers.
[0004] In another embodiment, a flavoring section is provided
downstream of the sodium bicarbonate-treated fibers and/or between
the activated carbon and the sodium bicarbonate-treated fibers.
[0005] In another preferred embodiment, a smoking article comprises
activated carbon and sodium bicarbonate-treated fibers. An optional
flavoring section can be provided along the filter of the smoking
article. The smoking article is preferably a traditional lit-end
cigarette or a non-traditional cigarette.
[0006] A preferred embodiment of a method of making a cigarette
filter comprises incorporating activated carbon, sodium
bicarbonate-treated fibers and a flavoring section into a
filter.
[0007] A preferred embodiment of a method of making a cigarette
comprises placing a paper wrapper around a tobacco column, and
attaching a cigarette filter to the tobacco column to form the
cigarette, wherein the cigarette filter includes activated carbon,
sodium bicarbonate-treated fibers and a flavoring section.
[0008] A preferred embodiment of methods of treating mainstream
smoke comprises heating or lighting tobacco in a cigarette to form
smoke, and drawing the smoke through the cigarette. Activated
carbon and sodium bicarbonate-treated fibers in the cigarette
remove selected constituents from the mainstream smoke. Optionally,
after the smoke passes through the sodium bicarbonate-treated
fibers, flavoring is added to the smoke in a flavoring section of
the cigarette.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0009] FIG. 1 illustrates a preferred embodiment of a cigarette
comprising a filter element including sodium bicarbonate-treated
fibers, activated carbon and an optional flavoring section.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0010] Cigarette filters and cigarettes are described that include
sorbent materials capable of removing selected constituents from
mainstream smoke. Methods of making the filters and cigarettes, as
well as methods of treating mainstream smoke in cigarettes that
include the filters, are also described.
[0011] In a preferred embodiment, the sorbent material comprises
activated carbon and sodium bicarbonate-treated fibers. The
activated carbon is disposed in the cigarette filter upstream from
the sodium bicarbonate-treated fibers, i.e., closer to the mouth
end of the cigarette filter than the activated carbon. Activated
carbon can remove certain constituents from mainstream smoke. It
has been determined, however, that activated carbon can produce a
less than totally satisfactory smoke subjective character. This
effect on the smoke subjective character can result from activated
carbon removing certain mainstream smoke constituents and
consequently changing the balance of the constituents in the
mainstream smoke that affect smoke subjective character.
[0012] It has further been determined that sodium
bicarbonate-treated fibers (i.e., NaHCO.sub.3-treated fibers) can
selectively remove selected constituents from mainstream cigarette
smoke that are partially removed by activated carbon. Moreover,
smoke may develop an activated carbon taste from passing through
the activated carbon.
[0013] The cigarette filter can optionally contain a flavoring
section. Mainstream smoke picks up flavoring in the flavoring
section, thereby affecting the subjective (organoleptic) character
of the smoke.
[0014] As used herein, the term "sorption" includes filtration by
adsorption and/or adsorption. Sorption encompasses interactions on
the outer surface of the sorbent, as well as interactions within
the pores and channels of the sorbent. In other words, a "sorbent"
is a substance that can condense or hold molecules of other
substances on its surface, and/or can take up other substances,
i.e., through penetration of the other substances into its inner
structure, or into its pores. Accordingly, the term "sorbent" as
used herein refers to either an adsorbent, an absorbent, or a
substance that can function as both an adsorbent and an
absorbent.
[0015] As used herein, the term "remove" refers to adsorption
and/or absorption of at least some portion of at least one
constituent of mainstream smoke.
[0016] The term "mainstream" tobacco smoke includes the mixture of
gases, solid particulate and aerosol that passes down the tobacco
column and is drawn through the filter end of a cigarette during a
puff.
[0017] Depending on its pore structure, activated carbon can be
characterized as being microporous, mesoporous and/or macroporous.
The term "microporous" generally refers to such materials with pore
sizes of about 2 nanometer (nm) or less. The term "mesoporous"
generally refers to such materials with pore sizes of about 2-50
nm. Materials with pore sizes of about 500 angstrom (.ANG.) or
larger may be referred to as "macroporous." See, for example, Pure
Appl. Chem., Vol. 73, No. 2, pp. 381-394 (2001). Microporous,
mesoporous and/or macroporous activated carbon can be chosen based
on the selected constituents that are desired to be removed from
mainstream smoke.
[0018] FIG. 1 illustrates a preferred embodiment of a cigarette 10
comprising a tobacco column 12 and a filter 14 attached to the
tobacco column by tipping paper. The filter 14 includes a first
plug 16, activated carbon 18, and sodium bicarbonate-treated fibers
20 downstream from the activated carbon 18. In the embodiment, the
filter 14 also includes a flavoring section 22 downstream from the
sodium bicarbonate-treated fibers, and a mouth end plug 24.
[0019] The embodiment of the cigarette depicted in FIG. 1 is a
traditional cigarette. However, activated carbon,
sodium-bicarbonate-treated fibers and flavoring section can also be
incorporated in non-traditional cigarettes. Non-traditional
cigarettes include, for example, smoking articles that include
combustible heat sources, such as the smoking articles described in
commonly-assigned U.S. Pat. No. 4,966,171, and cigarettes of
electrical smoking systems as described in commonly-assigned U.S.
Pat. Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,526; 5,692,525;
5,666,976 and 5,499,636, each of which is incorporated herein by
reference in its entirety.
[0020] The activated carbon can be in any suitable form in the
filter. For example, the activated carbon can be fibers, beads,
granules, one or more monolithic bodies and/or provided as a
coating on a substrate. The amount of beaded activated carbon in
the cigarette is preferably from about 50 mg to about 250 mg.
[0021] In a preferred embodiment, the activated carbon is in the
form of spherical beads to achieve a desired resistance-to-draw
(RTD). The beads can typically have an average diameter of from
about 0.2 mm to about 1 mm, with 0.3 mm to 0.5 mm beads being
preferred to achieve a desired RTD.
[0022] In another preferred embodiment, monolithic bodies of
activated carbon can have a cylindrical shape, as well as various
other shapes that may include oval or polygonal cross sectional
shapes, sheet-like, spherical, honeycomb, or other monolithic
shapes, and the like. The monolithic bodies can have different
sizes. For example, when used in monolithic form in a cigarette
filter, the activated carbon can be disc-shaped or cylindrical, and
preferably has a length of from about 2 mm to about 20 mm and a
diameter slightly less than the diameter the filter portion of the
cigarette. The monolithic body preferably has a pore size
distribution and size, e.g., a length or thickness, to provide a
suitably low RTD value during smoking of a cigarette.
[0023] In a preferred embodiment, the monolithic body is oriented
in a cigarette filter so that the body extends lengthwise along the
length dimension of the cigarette. Such orientation of the
activated carbon increases the length of the flow path through the
activated carbon traveled by mainstream smoke, thus exposing the
smoke to an increased total surface area of pores of activated
carbon. For a disc-shaped monolithic body, the inlet and outlet of
the disc (i.e., the opposed major surfaces) are preferably oriented
perpendicular to the longitudinal axis of the cigarette.
[0024] In a preferred embodiment, the carbon is in the form of
fibers having a diameter of from about 10 microns to about 25
microns, and a length of from about 100 microns to about 1000
microns, preferably from about 100 microns to about 500 microns.
The fibers can be intermingled with fiber tow material,
incorporated in paper, or form a plug.
[0025] In a preferred embodiment, the activated carbon can be
incorporated in the filter portion of a cigarette in various ways,
including, for example, with various materials, such as paper,
fibers and other materials, and/or the activated carbon can be
incorporated in a space, and/or void (cavity). For example,
carbon-containing paper can be inserted into a hollow portion of
the cigarette filter. The paper is preferably in the form of a
sheet material, such as crepe paper, filter paper or tipping paper.
However, other suitable materials, such as organic or inorganic
cigarette compatible materials, can also be used.
[0026] The activated carbon can be produced by processing a
suitable carbonaceous material or carbon-yielding precursor. For
example, the activated carbon can be produced from carbon beads, or
from natural or synthetic organic materials. In another preferred
embodiment, the activated carbon can be produced using isotropic
fibers derived from a suitable isotropic pitch precursor. The
manufacture of such carbon fibers is described, for example, in
U.S. Pat. No. 6,030,698, which is incorporated herein by reference
in its entirety. Other types of carbon fibers, such as fibers
derived from coal tar pitch, rayon, or heavy oils also can be used.
Suitable carbon fibers are commercially available from Ashland
Petroleum Company, located in Ashland, Ky., and from Anshan East
Asia Carbon Company, located in Anshan, China.
[0027] Carbonaceous materials are subjected to an activation
process to produce activated carbon having a desired pore
structure. Porous carbon materials are subjected to activation to
modify their existing pore structure by forming additional pores
and changing the existing pore size distribution.
[0028] The activation step utilizes any suitable oxygen-containing
environment, for example, steam, carbon dioxide, oxygen or
potassium hydroxide solution, at an elevated temperature, e.g.,
from about 400.degree. C. to about 900.degree. C. The environment
can also contain other gases, such as nitrogen. These gases react
with the carbon to produce a desired porous carbon structure.
Oxygen and nitrogen can also be chemically attached to the carbon
surface to enhance gas filtration selectivity based on
chemisorption, i.e., the formation of a covalent bond.
[0029] In a preferred embodiment, the carbonaceous material is
activated to a desired level of burn-off. The "burn-off" represents
the weight loss (i.e., weight loss=initial weight-final weight) of
the carbon that occurs during the activation process. During
activation, burn-off is preferably controlled to control the pore
size and pore surface area of the activated carbon. The BET
(Brunauer, Emmett and Teller) surface area of the activated carbon
is preferably from about 1000 m.sup.2/g to about 3,000
m.sup.2/g.
[0030] Sodium bicarbonate-treated fibers are provided in the
cigarette filter to remove selected constituents that remain in
mainstream smoke after the smoke has passed through the activated
carbon. For example, it has been determined that sulfur compounds
and acidic compounds that may be present in mainstream smoke may
not be effectively removed by activated carbon and consequently
remain in mainstream smoke after passing through the activated
carbon. It has further been determined that sodium
bicarbonate-treated fibers can remove such constituents from the
mainstream smoke, especially when the fibers are placed downstream
of the activated carbon in a cigarette filter.
[0031] By providing the sodium bicarbonate on fibers, the surface
area of the sodium bicarbonate to which mainstream smoke is exposed
in the cigarette can be enhanced. The fibers on which sodium
bicarbonate is provided can be of any suitable material. For
example, the fibers can be of materials including, but not limited
to, cellulose tow, cellulose acetate tow, mono cellulose, mono
acetate, propylene, polyester, polysulfone or polypropylene (e.g.,
Triad.RTM. polypropylene micro-cavity fibers available from
Honeywell International Inc. located in Morristown, N.J.). The
polymeric fibers preferably contain micro-cavities.
[0032] The fibers can be provided in the filter in any suitable
form. For example, the fibers can be in the form of a continuous
bundle, a mat, or the fibers can be cut into desired lengths, e.g.,
from about 0.5 mm to about 5 mm. The fibers preferably have a
diameter of from about 1 micron to about 100 microns, more
preferably from about 30 microns to about 60 microns.
[0033] The amount of sodium bicarbonate on the treated fibers in
the filter is preferably sufficient to effectively counteract, at
least in part, the perceived taste deficit associated with an
activated carbon by American smokers. In addition, the amount of
the sodium bicarbonate provided on the treated fibers is preferably
sufficient to be capable of removing a desired amount of selected
constituents, e.g., sulfur compounds (e.g., hydrogen sulfide and/or
carbonyl sulfide) and acidic compounds. Preferably, the amount of
sodium bicarbonate provided on the fibers is from about 5 mg to
about 100 mg per cigarette filter, more preferably 5 mg to 30 mg
and even more preferably 5 mg to 15 mg. Not wishing to be bound by
theory, it is believed that activated carbon in a cigarette filter
has lower selectivity (lower affinity) for sulfur containing
constituents of mainstream smoke, with a result that activated
carbon causes the relative amount (proportion) of sulfur compounds
in the filtered smoke to be altered (increased), and that change in
constituency contributes to the perceived taste deficit associated
with an activated carbon by American smokers. Thus, by placing
sodium bicarbonate downstream of the activated carbon in the
filter, it is believed that the relative amount of sulfur compounds
in the tobacco smoke can be reduced and thus render the smoke more
acceptable to the smoker.
[0034] In a preferred embodiment, the cigarette filter optionally
contains a flavoring (flavor release) section. The smoke picks up
flavoring in the flavoring section, thereby affecting the
subjective (organoleptic) character of the smoke. In a preferred
embodiment, the flavoring section is located downstream of the
sodium bicarbonate-treated fibers. In this embodiment, the
flavoring is released during passage of the mainstream smoke
through the flavoring section, thereby affecting the subjective
character of the mainstream smoke.
[0035] In other preferred embodiments, flavoring can be provided at
one or more different locations of the filter and/or the tobacco
column. For example, the flavoring section can be located between
the activated carbon and sodium bicarbonate-treated fibers, and/or
in the tobacco column.
[0036] The optional flavoring provided in the cigarette filter is
preferably at least one of menthol and mint. The amount of
flavoring is preferably sufficient to provide a desired amount of
flavoring into mainstream smoke that passes through the flavoring
section during smoking of a cigarette, so as to provide the desired
flavor to the smoke. For example, in a preferred embodiment, the
flavoring section can contain from about 5 mg to about 50 mg of
flavoring, such as menthol.
[0037] In a preferred embodiment, the flavoring is incorporated in
the flavoring section in a form that preferably minimizes release
and migration of the flavoring in the cigarette prior to smoking,
e.g., at ambient conditions, and preferably minimizes deactivation
of the activated carbon and sodium bicarbonate-treated fibers by
the flavoring. Consequently, the flavoring preferably enhances
subjective characteristics of the cigarette while not negatively
affecting the ability of the sorbent material to remove gas-phase
constituents from mainstream smoke. For example, the flavoring can
be encapsulated and provided in the form of a flavoring-release
additive, as described in commonly-assigned U.S. Application No.
2004/0129280, filed on Oct. 30, 2003, which is incorporated herein
by reference in its entirety. The flavoring-release additives can
be in the form of beads, films and inclusion complexes, and the
flavoring-release additives can be released at different minimum
temperatures. Accordingly, in a preferred embodiment, one or more
flavoring-release additives are located at one or more locations in
the cigarette at which at least the minimum temperate for release
of the flavoring is achieved during smoking.
[0038] An exemplary embodiment of a method of making a filter
comprises incorporating activated carbon and sodium
bicarbonate-treated fibers into a cigarette filter and/or a tobacco
column. In a preferred embodiment, flavoring is also incorporated
into the filter. Any conventional or modified method of making
cigarette filters may be used to incorporate the activated carbon,
sodium bicarbonate-treated fibers and flavoring in cigarettes.
[0039] Embodiments of methods for making cigarettes comprise
placing tipping paper around a tobacco rod, and attaching a
cigarette filter to the tobacco column to form the cigarette. The
cigarette filter contains activated carbon and sodium
bicarbonate-treated fibers. In a preferred embodiment, the filter
also contains flavoring.
[0040] Examples of suitable types of tobacco materials that may be
used include flue-cured, Burley, Md. or Oriental tobaccos, rare or
specialty tobaccos and blends thereof. The tobacco material can be
provided in the form of tobacco lamina; processed tobacco
materials, such as volume expanded or puffed tobacco, processed
tobacco stems, such as cut-rolled or cut-puffed stems,
reconstituted tobacco materials, or blends thereof. Tobacco
substitutes may also be used.
[0041] In cigarette manufacture, the tobacco is normally in the
form of cut filler, i.e., in the form of shreds or strands cut into
widths ranging from about 1/10 inch to about 1/20 inch, or even
1/40 inch. The lengths of the strands range from between about 0.25
inches to about 3.0 inches. The cigarettes may further comprise one
or more flavorants or other additives (e.g., burn additives,
combustion modifying agents, coloring agents, binders and the
like).
[0042] The resulting cigarettes can be manufactured to any desired
specification using standard or modified cigarette making
techniques and equipment. The cigarettes may range from about 50 mm
to about 120 mm in length.
[0043] Other preferred embodiments relate to methods of treating
mainstream smoke in a cigarette described above, which involve
selectively removing sulfur-containing compounds and/or acidic
compounds from the mainstream smoke by contacting the mainstream
smoke with bicarbonate treated fibers. The cigarette can contain
flavoring, which is released into the mainstream smoke.
[0044] "Smoking" of a cigarette means the heating or combustion of
the cigarette to form tobacco smoke. Generally, smoking of a
cigarette involves lighting one end of the cigarette and drawing
the cigarette smoke through the mouth end of the cigarette, while
the tobacco contained in the tobacco column undergoes a combustion
reaction. However, the cigarette may also be smoked by heating the
cigarette using an electrical heater, as described, for example, in
any one of commonly-assigned U.S. Pat. Nos. 6,053,176; 5,934,289;
5,591,368 and 5,322,075, each of which is incorporated herein by
reference in its entirety.
EXAMPLE
[0045] Tests were conducted to demonstrate the effectiveness of a
modified cigarette containing activated carbon and sodium
bicarbonate-treated fibers for removing certain gas-phase
constituents from mainstream smoke. Reference cigarettes were made
by incorporating 180 mg of activated carbon derived from coconut
shells into a cigarette.
[0046] Model 1 cigarettes were made by dissolving sodium
bicarbonate solid into a 20% aqueous solution and then applying the
solution onto cellulose acetate tow fibers in plugs located
adjacent the mouth end plug of the filter. The plugs had a length
of 9 mm. Excess liquid was removed from the plugs and the plugs
were allowed to dry at room temperature for 24 hours in a
convective oven. The plugs increased in weight by about 33 mg to 37
mg. The treated plugs were reinserted in the same cigarettes.
[0047] Model 2 cigarettes were made by incorporating 50 mg of
sodium bicarbonate powder downstream from 180 mg of activated
carbon in the filter.
[0048] 1R4F cigarettes, the reference cigarettes and the Model 1
and 2 cigarettes were tested under standard FTC conditions. No
significant change was observed for the RTD and dilution ratio for
the Model 1 and 2 cigarettes. Table 1 shows the test results for
the fourth puff for certain smoke constituents. The average
delivery values for the reference cigarettes are the percentage of
the 1R4F cigarette total delivery. For example, the reference
cigarettes provided 42.6% of the 1,2-propadiene delivery of the
1R4F cigarettes. As shown in Table 1, the Model 2 cigarettes
containing sodium bicarbonate powder did not yield any significant
change for the selected constituents with respect to the reference
cigarettes. In contrast, the composition of the smoke for the Model
1 cigarettes containing sodium bicarbonate-treated fibers was
significantly modified relative to the reference cigarettes.
Particularly, the Model 1 cigarettes significantly reduced various
smoke constituents, especially sulfur-containing compounds, such as
hydrogen sulfide and carbonyl sulfide. As a result of effectively
removing such sulfur-containing compounds from the smoke, the smoke
subjective character may have been improved.
TABLE-US-00001 TABLE 1 Reference Ave. Model 1 % Model 1 Model 2 %
Model 2 Delivery Reference Constituent Change STD (%) Change STD
(%) (%) STD (%) 1,2-propadiene -46 1 -8 1 42.6 0.4 1,3-butadiene
-95 5 -18 28 2.1 0.9 Acetaldehyde -100 0 -27 9 4.0 0.8 Acrolein N/A
-- NA -- 0 0 carbon dioxide -4 0.1 3 0 103.8 0.04 Propene -62 2 -1
2 20.1 0.5 Chloromethane -52 2 2 3 18.2 0.4 hydrogen -84 4 -9 3 5.6
0.8 cyanide Ethane -22 0.3 2 0 70.8 0.1 Hydrogen -52 2 -25 6 6.4
0.7 sulfide Carbonyl -56 1 -16 1 34.7 0.4 sulfide
[0049] While the invention has been described in detail with
reference to preferred embodiments thereof, it will be apparent to
one skilled in the art that various changes can be made, and
equivalents employed, without departing from the scope of the
invention.
* * * * *