U.S. patent application number 10/740584 was filed with the patent office on 2005-06-23 for smoking articles comprising copper-exchanged molecular sieves.
This patent application is currently assigned to Philip Morris USA Inc.. Invention is credited to Fournier, Jay A, Luan, Zhaohua.
Application Number | 20050133053 10/740584 |
Document ID | / |
Family ID | 34677909 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050133053 |
Kind Code |
A1 |
Fournier, Jay A ; et
al. |
June 23, 2005 |
Smoking articles comprising copper-exchanged molecular sieves
Abstract
Smoking articles which involve the use of a copper-exchanged
molecular sieve catalyst that is capable of removing NO and/or
NO.sub.2 from mainstream smoke are provided. The copper-exchanged
molecular sieve catalyst comprises a microporous molecular sieve
substrate having pores with an average diameter of from about 3
.ANG. to about 15 .ANG., where at least some of the pores of the
microporous molecular sieve substrate contain Cu.sup.+2 ions.
Methods for making cigarette filters and smoking articles using the
copper-exchanged molecular sieve catalyst, as well as methods for
smoking a cigarette comprising the copper-exchanged molecular sieve
catalyst, are also provided.
Inventors: |
Fournier, Jay A; (Richmond,
VA) ; Luan, Zhaohua; (Midlothian, VA) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Philip Morris USA Inc.
|
Family ID: |
34677909 |
Appl. No.: |
10/740584 |
Filed: |
December 22, 2003 |
Current U.S.
Class: |
131/334 ;
131/207; 131/342 |
Current CPC
Class: |
A24D 3/166 20130101;
A24D 3/12 20130101; A24D 1/002 20130101 |
Class at
Publication: |
131/334 ;
131/207; 131/342 |
International
Class: |
A24F 001/20; A24D
003/04 |
Claims
What is claimed is:
1. A smoking article comprising a copper-exchanged molecular sieve
catalyst, wherein the copper-exchanged molecular sieve catalyst is
capable of removing NO, NO.sub.2, or both from mainstream smoke
during smoking; wherein the copper-exchanged molecular sieve
catalyst comprises a microporous molecular sieve substrate having
pores with an average pore size of from about 3 .ANG. to about 15
.ANG..
2. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst comprises pores sufficiently small to
substantially exclude constituents in mainstream smoke having more
than 12 carbon atoms.
3. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst is capable of selectively removing more
benzene and 1,3-butadiene from mainstream smoke than molecules
larger than benzene.
4. The smoking article of claim 1, wherein the microporous
molecular sieve substrate has an average pore size of about 8 .ANG.
or smaller.
5. The smoking article of claim 4, wherein the microporous
molecular sieve substrate has an average pore size of about 6 .ANG.
or smaller.
6. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst is in particle form having an average mesh
size from about 20 mesh to about 60 mesh.
7. The smoking article of claim 1, wherein the microporous
molecular sieve substrate is a zeolite selected from the group
consisting of zeolite ZSM-5, zeolite A, zeolite X, zeolite Y,
zeolite K-G, zeolite ZK-5, zeolite Beta, zeolite ZK-4, and mixtures
thereof.
8. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst is Cu(II)-ZSM-5.
9. The smoking article of claim 1, further comprising a second
molecular sieve material, wherein the second molecular sieve
material is capable of selectively removing at least some of at
least one constituent of mainstream smoke that is not substantially
removed by the copper-exchanged molecular sieve catalyst.
10. The smoking article of claim 9, wherein the second molecular
sieve material comprises a catalytic metal other than
copper(II).
11. The smoking article of claim 10, wherein the catalytic metal is
selected from the group consisting of iron, manganese, and mixtures
thereof.
12. The smoking article of claim 1, wherein the smoking article is
selected from the group consisting of a cigarette, a pipe, a cigar
and a non-traditional cigarette.
13. The smoking article of claim 12, wherein the smoking article is
a cigarette.
14. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst is dispersed in the smoking mixture of the
smoking article.
15. The smoking article of claim 1, wherein the copper-exchanged
molecular sieve catalyst is incorporated into a filter portion of
the smoking article.
16. The smoking article of claim 1, comprising from about 10 mg to
about 300 mg of the copper-exchanged molecular sieve catalyst.
17. The smoking article of claim 16, comprising from about 50 to
about 150 mg of the copper-exchanged molecular sieve catalyst.
18. A cigarette filter comprising a copper-exchanged molecular
sieve catalyst, wherein the copper-exchanged molecular sieve
catalyst is capable of removing NO, NO.sub.2, or both from
mainstream smoke; wherein the copper-exchanged molecular sieve
catalyst comprises a microporous molecular sieve substrate having
pores with an average pore size of from about 3 .ANG. to about 15
.ANG.; and further wherein at least some of the pores of the
microporous molecular sieve substrate contain Cu.sup.+2 ions.
19. The cigarette filter of claim 18, wherein the microporous
molecular sieve substrate comprises pores sufficiently small enough
to substantially exclude constituents in mainstream smoke having
more than 12 carbon atoms.
20. The cigarette filter of claim 18, wherein the copper-exchanged
molecular sieve catalyst is capable of selectively removing benzene
and 1,3-butadiene from mainstream smoke, without removing molecules
larger than benzene.
21. The cigarette filter of claim 18, wherein the microporous
molecular sieve substrate has an average pore size of about 8 .ANG.
or smaller.
22. The cigarette filter of claim 21, wherein the microporous
molecular sieve substrate has an average pore size of about 6 .ANG.
or smaller.
23. The cigarette filter of claim 18, wherein the copper-exchanged
molecular sieve catalyst is in particle form having an average mesh
size from about 20 mesh to about 60 mesh.
24. The cigarette filter of claim 18, wherein the microporous
molecular sieve substrate is a zeolite selected from the group
consisting of zeolite ZSM-5, zeolite A, zeolite X, zeolite K-G,
zeolite ZK-5, zeolite Beta, zeolite ZK-4, and mixtures thereof.
25. The cigarette filter of claim 18, wherein the copper-exchanged
molecular sieve catalyst is Cu(II)-ZSM-5.
26. The cigarette filter of claim 18, further comprising a second
molecular sieve material, wherein the second molecular sieve
material is capable of selectively removing at least some of at
least one constituent of mainstream smoke that is not substantially
removed by the copper-exchanged molecular sieve catalyst.
27. The cigarette filter of claim 26, wherein the second molecular
sieve material comprises a catalytic metal other than
copper(II).
28. The cigarette filter of claim 27, wherein the catalytic metal
is selected from the group consisting of iron, manganese, and
mixtures thereof.
29. The cigarette filter of claim 18, comprising from about 10 mg
to about 300 mg of the copper-exchanged molecular sieve
catalyst.
30. The cigarette filter of claim 29, comprising from about 50 mg
to about 150 mg of the copper-exchanged molecular sieve
catalyst.
31. A method of making a cigarette filter, the method comprising
incorporating a copper-exchanged molecular sieve catalyst into a
cigarette filter, wherein the copper-exchanged molecular sieve
catalyst is capable of removing NO, NO.sub.2 or both from
mainstream smoke; wherein the copper-exchanged molecular sieve
catalyst comprises a microporous molecular sieve substrate having
pores with an average diameter of from about 3 .ANG. to about 15
.ANG.; and further wherein at least some of the pores of the
microporous molecular sieve substrate contain Cu.sup.+2 ions.
32. A method of making a cigarette, the method comprising: (i)
providing a cut filler comprising a copper(II) exchanged molecular
sieve catalyst interspersed in the cut filler to a cigarette making
machine to form a tobacco column; (ii) placing a paper wrapper
around the tobacco column to form a tobacco rod; and (iii)
attaching a cigarette filter to the tobacco rod to form the
cigarette.
33. A method of smoking the cigarette of claim 13, comprising
lighting or heating the cigarette to form smoke and drawing the
smoke through the cigarette, wherein during the smoking of the
cigarette, the copper-exchanged molecular sieve catalyst reduces
the concentration of at least one of NO and NO.sub.2 in the
mainstream smoke.
Description
BACKGROUND
[0001] Certain filter materials have been suggested for
incorporation into cigarette filters, including cotton, paper,
cellulose, and certain synthetic fibers. However, such filter
materials generally only remove particulate and condensable
components from tobacco smoke. Thus, they are usually not optimal
for the removal of certain gaseous components from tobacco smoke,
e.g., volatile organic compounds.
SUMMARY
[0002] Copper-exchanged molecular sieve catalysts for the removal
of NO.sub.2 and/or NO from mainstream smoke are provided.
[0003] In one embodiment, smoking articles, filters and/or cut
filler are provided, which comprise copper-exchanged molecular
sieve catalyst, wherein the copper-exchanged molecular sieve
catalyst is capable of removing at least one of NO and NO.sub.2
from mainstream smoke, wherein the copper-exchanged molecular sieve
catalyst comprises a microporous molecular sieve substrate having
pores with an average pore size of from about 3 .ANG. to about 15
.ANG., and further wherein at least some of the pores of the
microporous molecular sieve substrate contain Cu.sup.+2 ions.
[0004] In another embodiment, the microporous molecular sieve
substrate comprises pores sufficiently small enough to
substantially exclude constituents in mainstream smoke having more
than 12 carbon atoms. In another preferred embodiment, the
copper-exchanged molecular sieve catalyst is capable of selectively
removing more benzene and/or 1,3-butadiene from mainstream smoke,
than molecules larger than benzene. Preferably, the microporous
molecular sieve substrate has pores with an average pore size of
about 8 .ANG. or smaller and more preferably about 6 .ANG. or
smaller. In a further embodiment, the copper-exchanged molecular
sieve catalyst is in particle form having an average mesh size of
from about 20 mesh to about 60 mesh.
[0005] In an embodiment, the microporous molecular sieve substrate
may be a zeolite selected from the group consisting of zeolite
ZSM-5, zeolite A, zeolite X, zeolite Y, zeolite K-G, zeolite ZK-5,
zeolite Beta, zeolite ZK-4, and mixtures thereof. In a preferred
embodiment, the cooper-exchanged molecular sieve catalyst is
Cu(II)-ZSM-5.
[0006] In an embodiment, smoking articles, cigarette filters and/or
cut filler may further comprise a second molecular sieve material,
wherein the second molecular sieve material is capable of
selectively removing at least some of at least one constituent of
mainstream smoke that is not substantially removed by the
copper-exchanged molecular sieve catalyst. Preferably, the second
molecular sieve material comprises a catalytic metal other than
copper(II). Preferably, the catalytic metal is selected from the
group consisting of iron, manganese, copper oxide, and mixtures
thereof.
[0007] Examples of smoking articles that may comprise the
copper-exchanged molecular sieve catalyst include, but are not
limited to, the group consisting of cigarettes, pipes, cigars and
non-traditional cigarettes. Preferably, the smoking article is a
cigarette. In a preferred embodiment, the copper-exchanged
molecular sieve catalyst is incorporated into the smoking mixture
and/or a filter portion of the smoking article.
[0008] In an embodiment, the smoking articles and filters may
comprise from about 10 mg to about 300 mg of the copper-exchanged
molecular sieve catalyst, or preferably from about 50 mg to about
150 mg of the copper-exchanged molecular sieve catalyst.
[0009] In another embodiment, methods for making a cigarette filter
are provided, which comprise incorporating a copper-exchanged
molecular sieve catalyst into a cigarette filter, wherein the
copper-exchanged molecular sieve catalyst is capable of removing at
least one of NO and NO.sub.2 from mainstream smoke, wherein the
copper-exchanged molecular sieve catalyst comprises a microporous
molecular sieve substrate having pores with an average pore size of
from about 3 .ANG. to about 15 .ANG., and further wherein at least
some of the pores of the microporous molecular sieve substrate
contain Cu.sup.+2 ions.
[0010] In another embodiment, methods for smoking a cigarette
comprising a copper-exchanged molecular sieve catalyst are
provided, which involve lighting the cigarette to form smoke and
drawing the smoke through the cigarette, wherein during the smoking
of the cigarette, the copper-exchanged molecular sieve catalyst
removes NO and/or NO.sub.2 from the mainstream smoke.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a partially exploded perspective view of a
cigarette incorporating one embodiment wherein folded paper
containing copper-exchanged molecular sieve catalyst is inserted
into a hollow portion of a tubular filter element of the
cigarette.
[0012] FIG. 2 is partially broken-away perspective view of another
embodiment wherein copper-exchanged molecular sieve catalyst is
incorporated in folded paper and inserted into a hollow portion of
a first free-flow sleeve of a tubular filter element next to a
second free-flow sleeve.
[0013] FIG. 3 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a plug-space-plug filter element.
[0014] FIG. 4 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a three-piece filter element having
three plugs.
[0015] FIG. 5 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a four-piece filter element having a
plug-space-plug arrangement and a hollow sleeve.
[0016] FIG. 6 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a three-part filter element having two
plugs and a hollow sleeve.
[0017] FIG. 7 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a two-part filter element having two
plugs.
[0018] FIG. 8 is a partially broken-away perspective view of
another embodiment wherein copper-exchanged molecular sieve
catalyst is incorporated in a filter element which may be used in a
smoking article.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] Copper-exchanged molecular sieve catalysts for selective and
effective removal of certain selected constituents of mainstream
tobacco smoke are provided. Preferably, other constituents in
mainstream smoke, such as those relating to flavor, will preferably
not be removed to any great extent. By "removed" is meant that the
concentration of at least some of the NO.sub.x constituents in
mainstream smoke is lowered. This can be accomplished by a variety
of mechanisms. For example, the NO.sub.x constituents may
chemically react with the copper-exchanged molecular sieve
catalysts, i.e., be reduced directly by the copper ion.
Alternatively, the copper-exchanged molecular sieve catalyst may
catalyze the conversion of the NO.sub.x constituents into other
compounds. Further, the NO.sub.x constituents may be sequestered
within the pores of the microporous molecular sieve substrate, thus
removed from mainstream tobacco smoke before reaching the smoker.
By combining catalytic and sorbent materials, tailored or optimized
for a particular selectivity, a desired removal of multiple
selected constituents from mainstream smoke can be achieved.
[0020] The term "sorption" denotes filtration through absorption
and/or adsorption. Sorption is intended to cover interactions on
the outer surface of the sorbent, as well as interactions within
the pores, such as channels or cavities of the sorbent. In other
words, a sorbent is a substance that has the ability to condense or
hold molecules of other substances on its surface and/or the
ability to take up another substance, i.e., through penetration of
the other substance into its inner structure or into its pores. The
term adsorption also denotes filtration through physical sieving,
i.e., capture of certain constituents in the pores of the
carbon-modified sorbent. The term "sorbent" as used herein refers
to either an adsorbent, an absorbent, or a substance that functions
as both an adsorbent and an absorbent.
[0021] As an example, the combination of specialized sorbents in
different portions of a smoking article, such as in the tobacco rod
and in the filter portion of a cigarette, a multi-stage
multifunctional system is provided wherein a plurality of selected
constituents may be more effectively accomplished by a combination
of selective materials than by any single broadly catalytic or
sorbent material or a combination of more broadly sorbent
materials.
[0022] Preferably, the smoking articles, tobacco compositions and
filters will incorporate copper-exchanged molecular sieves having
pore sizes and other characteristics that will remove selected
constituents from mainstream smoke. By incorporating a second
molecular sieve material that is tailored for removal of at least
some of a different selected constituent of mainstream smoke in a
smoking article, the composition of the mainstream smoke may be
adjusted. A combination of different materials can be used to
achieve improved multifunctional removal of selectively targeted
constituents of mainstream smoke, while allowing other smoke
constituents (such as flavor constituents) to remain in the
mainstream smoke.
[0023] The abbreviation "NO.sub.x" as used herein includes either
or both of NO and NO.sub.2. Molecular sieve materials containing
copper ions, such as copper-exchanged zeolite, have been found to
be a highly efficient and selective catalyst of the conversion of
ammonia and NO.sub.x to molecular nitrogen and water at moderately
high temperatures, i.e., 400.degree. C., through reactions such as
the following:
4NH.sub.3+4NO+O.sub.2.fwdarw.4N.sub.2+6H.sub.2O;
and
4NH.sub.3+2NO+2NO.sub.2.fwdarw.4N.sub.2+6H.sub.2O.
[0024] However, copper-exchanged zeolite catalysts can be affected
by common constituents of smoke. In particular, these catalysts can
be inactivated by the presence of SO.sub.2, and may be inactivated
by organic compounds that are adsorbed in the pores of some
molecular sieve materials. For example, where the pores of the
molecular sieve are large enough to admit larger organic compounds,
such as components larger than benzene which can form tar, these
compounds can block the pores of the molecular sieve so that the
catalytic reduction of NO.sub.x is impaired. In a preferred
embodiment, molecular sieve materials that exclude high molecular
weight organic compounds can achieve highly effective and selective
reduction of NO and NO.sub.2 in mainstream tobacco smoke.
[0025] The term "molecular sieve" as used herein refers to an
ordered porous material, such as crystalline aluminosilicates,
commonly called zeolites, or crystalline aluminophosphates,
mesoporous silicates, and mesoporous aluminosilicates. A molecular
sieve as used herein further refers to a material having pores with
dimensions less than about 500 .ANG., preferably less than 300
.ANG., including microporous and mesoporous molecular sieves. The
term "microporous molecular sieves" generally refers to such
materials having pore sizes below about 20 .ANG. while the term
"mesoporous molecular sieves" generally refers to such materials
with pore sizes of about 20-500 .ANG., preferably 20 to 300
.ANG..
[0026] In a copper-exchanged molecular sieve, ions of copper are
incorporated into the molecular sieve substrate by displacing ions
of the substrate and thereby become part of the molecular matrix of
the substrate.
[0027] Pores of the preferred zeolite molecular sieve substrate may
be more or less uniform and may have pore dimensions over a range
of sizes. Synthetic zeolite materials may have more uniform pore
dimensions and a more ordered structure. Various zeolite types are
described, for example, in U.S. Pat. No. 3,702,886 (zeolite ZSM-5),
U.S. Pat. No. 2,882,243 (zeolite A), U.S. Pat. No. 2,882,244
(zeolite X), U.S. Pat. No. 3,130,007 (zeolite Y), U.S. Pat. No.
3,055,654 (zeolite K-G), U.S. Pat. No. 3,247,195 (zeolite ZK-5),
U.S. Pat. No. 3,308,069 (zeolite Beta), U.S. Pat. No. 3,314,752
(zeolite ZK-4). A source of natural zeolite in North America is the
St. Cloud Mining Company, Truth or Consequences, N. Mex.
[0028] Molecular sieve materials derive their name from the ability
to selectively exclude or adsorb molecules from or within pores
including interior channels depending on the dimensions of the
molecules. A copper-exchanged molecular sieve having a pore size
that is small enough to substantially exclude higher molecular
weight components of tobacco smoke provides improved selectivity
and effectiveness for selective catalytic reduction of NO.sub.x
from mainstream tobacco smoke. The molecular sieve material may be
chosen according to its pore diameter as determined by x-ray or
neutron diffraction methods. For example a microporous molecular
sieve may be chosen with a mean pore size of less than about 15
.ANG., e.g., less than about 8 .ANG., preferably less than about 6
.ANG.. Such molecular sieves effectively exclude compounds with a
larger molecular dimension. Alternatively, a molecular sieve
material may be chosen by measurements under conditions that
simulate the environment in which it will function. For example, a
molecular sieve may be chosen which significantly or substantially
excludes organic molecules having 4, 6, 8, 10, 12 or more carbon
atoms. Alternatively, a molecular sieve material may be chosen by
its ability to significantly or substantially exclude hydrocarbon
molecules which comprise the tar component of tobacco smoke. Or, a
molecular sieve material may be chosen by its ability to
significantly or substantially exclude a selected category of
organic molecules such as cyclic hydrocarbons of more than four
carbons, aromatic hydrocarbons (i.e., benzene), larger alkanes or
the like. The ability of a molecular sieve material to exclude
molecules can be determined by measuring adsorption of a given
compound in a conventional test apparatus.
[0029] The adsorption or exclusion of a given molecule can be
expressed relative to adsorption of a standard molecular compound
such as N.sub.2. When comparing the adsorption of molecular sieve
materials of a given compound as a function of pore size, one
generally observes a sharp drop in adsorption of a compound as the
pore size of the molecular sieve materials approaches a cut-off
size. The cut-off pore size for a given compound may be identified
by comparing similarly structured materials with a range of pore
sizes. The cut-off pore size corresponds to the maximum pore size
at which less than about 95% of the maximum adsorption of that
compound is adsorbed in a range of similar porous materials having
pore sizes both larger and smaller than the molecular dimension of
the compound. Similar materials means materials of similar atomic
composition, i.e., zeolites.
[0030] For purposes of categorizing the molecular sieves, to
significantly exclude a certain molecular compound means that a
molecular sieve material adsorbs an amount of that compound at or
below the midpoint of a size exclusion curve, i.e., it adsorbs less
than about 50% of the maximal adsorption of that compound by a
similar molecular sieve material with a pore size substantially
larger than the cutoff size pore size. To substantially exclude a
certain molecular compound means that a molecular sieve material
adsorbs less than about 10% of the maximal adsorption of that
compound by similar molecular sieve material with a pore size
substantially larger than the cut off pore size for that
compound.
[0031] By choosing, or modifying, a molecular sieve material to
have a pore size that exclude organic compounds of about the size
of octane or larger compounds, or to exclude molecules the size of
benzene and larger, the interior pores of the molecular sieve can
be maintained sufficiently free of organic compounds to achieve
improved effectiveness for the reduction of NO.sub.x.
[0032] In an alternative embodiment, the selective reduction of
NO.sub.x may be combined with selective adsorption of selected
small organic compounds by use of a molecular sieve substrate
having pores that admit molecules of selected constituents, e.g.,
benzene or 1,3-butadiene, while excluding larger constituents of
mainstream smoke. By selectively adsorbing smaller molecules that
do not substantially impair NO.sub.x reduction, a desirable
multifunctional capability is achieved with effective selective
reduction of NO.sub.x.
[0033] In a preferred embodiment, the copper-exchanged molecular
sieve material is provided in particle form which may be mixed into
the smoking mixture of the tobacco rod of a cigarette where the
increased temperature of the zone adjacent to the burning zone of
the tobacco rod promotes catalytic activity.
[0034] In another embodiment, a plurality of selective molecular
sieve materials may be incorporated in a smoking article to achieve
multifunctional reduction of selected components of mainstream
smoke. For example, molecular sieve materials exchanged with
different catalytic metals, including oxide forms of copper, which
can provide improved selective catalysis of CO to CO.sub.2, may be
combined in the tobacco rod with copper ion exchanged molecular
sieve. In alternative embodiments, copper ion exchanged molecular
sieve materials may be combined with molecular sieve materials
comprising zinc, vanadium, chromium, manganese, iron, cobalt,
rhodium, palladium, platinum, and/or molybdenum; with manganese and
iron being preferred. Molecular sieve materials having pore sizes
that admit higher molecular weight compounds may be incorporated
into smoking articles in combination with copper ion exchanged
materials having smaller pore sizes. For example, molecular sieve
materials having pore sizes of about 15 .ANG. or larger can be
further incorporated into smoking articles.
[0035] The preferred molecular sieve substrates for making a
material designed for the removal of NO.sub.x include at least one
of ZSM-5 and Y-type zeolite ion exchanged with Cu.sup.+2 ions.
ZSM-5 type zeolite is most preferred because it has well ordered
pores of less than about 6 .ANG.. The copper ion exchanged form of
ZSM-5 is designated Cu(II)-ZSM-5 and is the most preferred copper
ion exchanged molecular sieve material.
[0036] The copper-exchanged molecular sieve may be made by any
suitable method. In a preferred method, the metal may be dispersed
as a salt solution and impregnated into the molecular sieve where
it is incorporated by cation exchange. For example, to make a
Cu(II)-ZSM-5 molecular sieve material, the zeolite molecular sieve
may be soaked for several hours (e.g., 8-24 hours) in a solution
(i.e., 1 M) of CuCl.sub.2 after which the molecular sieve is
briefly washed and thoroughly dried at elevated temperature (e.g.,
100-400.degree. C. for 2-24 hours).
[0037] In one embodiment, copper-exchanged molecular sieve material
is incorporated into cut tobacco filler or other smoking material,
which may then be included in the tobacco rod of a cigarette. The
copper-exchanged molecular sieve can be incorporated into the
smoking mixture in a number of ways. For example, the
copper-exchanged molecular sieve can be added as a powder to the
cut filler material supplied to a cigarette making machine.
[0038] The amount of copper-exchanged molecular sieve incorporated
into the smoking mixture can be selected as a function of the
amount of constituents in the tobacco smoke to be removed. As an
example, the smoking mixture may contain from 1% to 50% by weight
of the copper-exchanged molecular sieve, preferably from about 5%
to about 15% by weight. In a method for making cigarettes, the
method comprises: (i) providing a cut filler comprising the
copper-exchanged molecular sieve preferably in the form of powder
to a cigarette making machine to form a tobacco column; (ii)
placing a paper wrapper around the tobacco column to form a tobacco
rod; and (iii) attaching the cigarette filter to the tobacco rod to
form the cigarette.
[0039] Examples of suitable types of tobacco materials that may be
used include flue-cured, Burley, Maryland 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. The tobacco
materials may include tobacco substitutes.
[0040] In cigarette manufacture, the tobacco is normally employed
in the form of cut filler, i.e., in the form of shreds or strands
cut into widths ranging from about {fraction (1/10)} inch to about
{fraction (1/20)} inch or even {fraction (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, etc.).
[0041] 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. Generally, a regular cigarette is about 70 mm long, a
"King Size" is about 85 mm long, a "Super King Size" is about 100
mm long, and a "Long" is usually about 120 mm in length. The
circumference is from about 15 mm to about 30 mm in circumference,
and preferably around 25 mm. The packing density is typically
between the range of about 100 mg/cm.sup.3 to about 300
mg/cm.sup.3, and preferably 150 mg/cm.sup.3 to about 275
mg/cm.sup.3.
[0042] Yet another embodiment relates to methods of smoking the
cigarettes described above, which involve lighting a cigarette to
form smoke and drawing the smoke through the cigarette, wherein
during the smoking of the cigarette, the metal exchanged molecular
sieve is capable of catalytically reducing and optionally adsorbing
one or more selected components from mainstream smoke.
[0043] "Smoking" of a cigarette means the heating or combustion of
the cigarette to form smoke, which can be drawn through the
cigarette, e.g., via a smoking machine or person. 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 therein undergoes a
combustion reaction. However, the cigarette need not be combusted.
For example, the cigarette may be smoked by heating the cigarette
using an electrical heater, as described in commonly-assigned U.S.
Pat. Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,525; 5,666,976;
and 5,499,636, for example.
[0044] In a preferred embodiment, a copper-exchanged molecular
sieve sorbent as described above is incorporated into or onto a
support such as lightly or tightly folded paper inserted into a
hollow portion of the cigarette filter. The support is preferably
in the form of a sheet material such as crepe paper, filter paper,
or tipping paper. However, other suitable support materials such as
organic or inorganic cigarette compatible materials can also be
used.
[0045] The copper-exchanged molecular sieve catalyst material may
be located in a filter portion of a smoking article in which it can
act as a sorbent.
[0046] Any conventional or modified filter design may be used,
which comprises the copper-exchanged molecular sieve catalyst.
Examples of filter designs include, but are not limited to a mono
filter, a dual filter, a triple filter, a cavity filter, a recessed
filter or a free-flow filter. Mono filters typically contain a
variety of cellulose acetate tow or cellulose paper materials. Pure
mono cellulose filters or paper filters offer good tar and nicotine
retention, and are highly degradable. The copper-exchanged
molecular sieve catalyst may be incorporated into the cellulose
filters or paper filters. Dual filters usually comprise a cellulose
acetate mouth side and a pure cellulose segment or cellulose
acetate segment, with copper-exchanged molecular sieve catalyst on
the smoking material or tobacco side. The length and pressure drop
of the two segments of the dual filter can be adjusted to provide
optimal adsorption, while maintaining acceptable draw resistance.
Triple filters may have mouth and smoking material or tobacco side
segments, while the middle segment comprises a material or paper
containing the copper-exchanged molecular sieve catalyst. Cavity
filters have two segments, e.g., acetate-acetate, acetate-paper or
paper-paper, separated by a cavity containing the copper-exchanged
molecular sieve catalyst. Recessed filters have an open cavity on
the mouth side, and typically incorporate the copper-exchanged
molecular sieve sorbent into the plug material. The filters may
also optionally be ventilated, and/or comprise additional sorbents
(such as charcoal or magnesium silicate), catalysts, flavors, or
other like additives.
[0047] FIG. 1 illustrates an exemplary cigarette 2 including a
tobacco rod 4, a filter portion 6, and a mouthpiece filter plug 8.
As shown, copper-exchanged molecular sieve catalyst can be loaded
onto folded paper 10 inserted into a hollow cavity, such as the
interior of a free-flow sleeve 12 forming part of the filter
portion 6.
[0048] FIG. 2 shows a cigarette 2 including a tobacco rod 4 and a
filter portion 6, wherein folded paper 10 is located in the hollow
cavity of a first free-flow sleeve 13 located between the
mouthpiece filter 8 and a second free-flow sleeve 15. The paper 10
can be used in forms other than as a folded sheet. For instance,
the paper 10 can be deployed as one or more individual strips, a
wound roll, or the like. In whichever form, a desired amount of
copper-exchanged molecular sieve catalyst can be provided in the
cigarette filter portion by a combination of the coated amount of
reagent/area of the paper and/or the total area of coated paper
employed in the filter (e.g., higher amounts of copper-exchanged
molecular sieve catalyst can be provided using larger pieces of
coated paper). In the cigarettes shown in FIGS. 1 and 2, the
tobacco rod 4 and the filter portion 6 are joined together with
tipping paper 14. In both cigarettes, the filter portion 6 may be
held together by filter overwrap 11.
[0049] Copper-exchanged molecular sieve catalyst can be
incorporated into the filter paper in a number of ways. For
example, copper-exchanged molecular sieve catalyst can be mixed
with water to form a slurry. The slurry can then be coated onto
pre-formed filter paper and allowed to dry. The filter paper can
then be incorporated into the filter portion of a cigarette in the
manner shown in FIGS. 1 and 2. Alternatively, dried paper can be
wrapped into a plug shape and inserted into a filter portion of the
cigarette. For example, the paper can be wrapped into a plug shape
and inserted as a plug into the interior of a free-flow filter
element such as a polypropylene or cellulose acetate sleeve. In
another arrangement, the paper can comprise an inner liner of such
a free-flow filter element.
[0050] Alternatively and preferably, copper-exchanged molecular
sieve catalyst is added to the filter paper during the paper-making
process. For example, copper-exchanged molecular sieve catalyst can
be mixed with bulk cellulose to form a cellulose pulp mixture. The
mixture can be formed into filter paper by any suitable method.
[0051] In another preferred embodiment, copper-exchanged molecular
sieve catalyst is incorporated into the fibrous material of the
cigarette filter portion itself. Such filter materials include, but
are not limited to, fibrous filter materials including paper,
cellulose acetate fibers, and polypropylene fibers. This embodiment
is illustrated in FIG. 3, which shows a cigarette 2 comprised of a
tobacco rod 4 and a filter portion 6 in the form of a
plug-space-plug filter having a mouthpiece filter 8, a plug 16, and
a space 18. The plug 16 can comprise a tube or solid piece of
material, such as polypropylene or cellulose acetate fibers. The
tobacco rod 4 and the filter portion 6 are joined together with
tipping paper 14. The filter portion 6 may include a filter
overwrap 11. The filter overwrap 11 containing traditional fibrous
filter material and copper-exchanged molecular sieve catalyst can
be incorporated in or on the filter overwrap 11, such as by being
coated thereon. Alternatively, copper-exchanged molecular sieve
catalyst can be incorporated in the mouthpiece filter 8, in the
plug 16, and/or in the space 18. Moreover, copper-exchanged
molecular sieve catalyst can be incorporated in any element of the
filter portion of a cigarette. For example, the filter portion may
consist only of the mouthpiece filter 8 and copper-exchanged
molecular sieve catalyst can be incorporated in the mouthpiece
filter 8 and/or in the tipping paper 14.
[0052] FIG. 4 shows a cigarette 2 comprised of a tobacco rod 4 and
filter portion 6. This arrangement is similar to that of FIG. 3
except the space 18 contains copper-exchanged molecular sieve
catalyst or a plug 15 made of material such as fibrous
polypropylene or cellulose acetate containing copper-exchanged
molecular sieve catalyst. As in the previous embodiment, the plug
16 can be hollow or solid and the tobacco rod 4 and filter portion
6 are joined together with tipping paper 14. There is also a filter
overwrap 11.
[0053] FIG. 5 shows a cigarette 2 comprised of a tobacco rod 4 and
a filter portion 6 wherein the filter portion 6 includes a
mouthpiece filter 8, a filter overwrap 11, tipping paper 14 to join
the tobacco rod 4 and filter portion 6, a space 18, a plug 16, and
a hollow sleeve 20. Copper-exchanged molecular sieve catalyst can
be incorporated into one or more elements of the filter portion 6.
For instance, copper-exchanged molecular sieve catalyst can be
incorporated into the sleeve 20, or copper-exchanged molecular
sieve catalyst can be filled into the space within the sleeve 20.
The plug 16 and sleeve 20 can be made of material, such as fibrous
polypropylene or cellulose acetate containing copper-exchanged
molecular sieve catalyst. As in the previous embodiment, the plug
16 can be hollow or solid.
[0054] FIGS. 6 and 7 show further modifications of the filter
portion 6. In FIG. 6, cigarette 2 is comprised of a tobacco rod 4
and filter portion 6. The filter portion 6 includes a mouthpiece
filter 8, a filter overwrap 11, a plug 22, and a sleeve 20.
Copper-exchanged molecular sieve catalyst can be incorporated in
one or more of these filter elements. In FIG. 7, the filter portion
6 includes a mouthpiece filter 8 and a plug 24. Copper-exchanged
molecular sieve catalyst can be incorporated in one or more of
these filter elements. Like the plug 16, the plugs 22 and 24 can be
solid or hollow. In the cigarettes shown in FIGS. 6 and 7, the
tobacco rod 4 and filter portion 6 are joined together by tipping
paper 14.
[0055] Various techniques can be used to apply copper-exchanged
molecular sieve catalyst to filter fibers or other substrate
supports. For example, copper-exchanged molecular sieve catalyst
can be added to the filter fibers before they are formed into a
filter cartridge, e.g., a tip for a cigarette. Copper-exchanged
molecular sieve catalyst can be added to the filter fibers, for
example, in the form of a dry powder or a slurry. If
copper-exchanged molecular sieve catalyst is applied in the form of
a slurry, the fibers are allowed to dry before they are formed into
a filter cartridge.
[0056] In another preferred embodiment, copper-exchanged molecular
sieve sorbent is employed in a hollow portion of a cigarette
filter. For example, some cigarette filters have a plug/space/plug
configuration in which the plugs comprise a fibrous filter material
and the space is a void between the two filter plugs. That void can
contain the copper-exchanged molecular sieve catalyst. An example
of this embodiment is shown in FIG. 3. Copper-exchanged molecular
sieve catalyst can be in granular form, or can be loaded onto a
suitable support, such as a fiber or thread.
[0057] In another embodiment, the copper-exchanged molecular sieve
catalyst is employed in a filter portion of a cigarette for use
with a smoking device as described in U.S. Pat. No. 5,692,525, the
entire content of which is hereby incorporated by reference. FIG. 8
illustrates one type of construction of a cigarette 100 which can
be used with an electrical smoking device. The cigarette 100
includes a tobacco rod 60 and a filter portion 62 joined by tipping
paper 64. The filter portion 62 preferably contains a tubular
free-flow filter element 102 and a mouthpiece filter plug 104. The
free-flow filter element 102 and mouthpiece filter plug 104 may be
joined together as a combined plug 110 with plug wrap 112. The
tobacco rod 60 can have various forms incorporating one or more of
the following items: an overwrap 71, another tubular free-flow
filter element 74, a cylindrical tobacco plug 80 preferably wrapped
in a plug wrap 84, a tobacco web 66 comprising a base web 68 and
tobacco flavor material 70, and a void space 91. The free-flow
filter element 74 provides structural definition and support at the
tipped end 72 of the tobacco rod 60. At the free end 78 of the
tobacco rod 60, the tobacco web 66 together with overwrap 71 are
wrapped about cylindrical tobacco plug 80. Various modifications
can be made to a filter arrangement for such a cigarette
incorporating the copper-exchanged molecular sieve catalyst.
[0058] In such a cigarette, copper-exchanged molecular sieve
catalyst can be incorporated in various ways, such as by being
loaded onto paper or other substrate material which is fitted into
the passageway of the tubular free-flow filter element 102 therein.
It may also be deployed as a liner or a plug in the interior of the
tubular free-flow filter element 102. Alternatively,
copper-exchanged molecular sieve catalyst can be incorporated into
the fibrous wall portions of the tubular free-flow filter element
102 itself. For instance, the tubular free-flow filter element or
sleeve 102 can be made of suitable materials such as polypropylene
or cellulose acetate fibers, and copper-exchanged molecular sieve
catalyst can be mixed with such fibers prior to or as part of the
sleeve forming process.
[0059] In another embodiment, copper-exchanged molecular sieve
catalyst can be incorporated into the mouthpiece filter plug 104
instead of in the element 102. However, as in the previously
described embodiments, copper-exchanged molecular sieve catalyst
may be incorporated into more than one constituent of a filter
portion, such as by being incorporated into the mouthpiece filter
plug 104 and into the tubular free-flow filter element 102. The
filter portion 62 of FIG. 8 can also be modified to create a void
space into which copper-exchanged molecular sieve catalyst can be
inserted. Preferably at least 10%, 20%, 30%, 40%, 50% or more of
the selected constituent is removed from the tobacco smoke by the
catalyst.
[0060] 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.
[0061] All of the above-mentioned references are herein
incorporated by reference in their entirety to the same extent as
if each individual reference was specifically and individually
indicated to be incorporated herein by reference in its
entirety.
* * * * *