U.S. patent application number 11/641003 was filed with the patent office on 2007-07-26 for corrugated catalytic cigarette paper and cigarettes comprising the same.
This patent application is currently assigned to Philip Morris USA Inc.. Invention is credited to Shalva Gedevanishvili, Ping Li, Firooz Rasouli, Weijun Zhang.
Application Number | 20070169786 11/641003 |
Document ID | / |
Family ID | 38441500 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070169786 |
Kind Code |
A1 |
Li; Ping ; et al. |
July 26, 2007 |
Corrugated catalytic cigarette paper and cigarettes comprising the
same
Abstract
A catalyst-modified corrugated cigarette paper wrapper comprises
a fibrous web, an optional web-filler material supported by the
web, and catalyst particles supported by the web and/or the
web-filler material. In cigarettes comprising the catalyst-modified
corrugated cigarette paper, the corrugations define
axially-extending channels that can run the length of a tobacco
rod. The corrugations can increase the catalytic efficiency of
catalyst particles that are incorporated within the
catalyst-modified corrugated cigarette paper wrapper.
Inventors: |
Li; Ping; (Glen Allen,
VA) ; Rasouli; Firooz; (Midlothian, VA) ;
Gedevanishvili; Shalva; (Richmond, VA) ; Zhang;
Weijun; (Richmond, VA) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Philip Morris USA Inc.
Richmond
VA
|
Family ID: |
38441500 |
Appl. No.: |
11/641003 |
Filed: |
December 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60754897 |
Dec 30, 2005 |
|
|
|
Current U.S.
Class: |
131/365 ;
131/360 |
Current CPC
Class: |
A24B 15/28 20130101;
A24B 15/286 20130101; A24B 15/282 20130101; A24B 15/288 20130101;
A24B 15/287 20130101; A24D 1/02 20130101 |
Class at
Publication: |
131/365 ;
131/360 |
International
Class: |
A24B 1/00 20060101
A24B001/00 |
Claims
1. A cigarette comprising: a tobacco rod wrapped in a cigarette
wrapper, wherein the cigarette wrapper comprises a
catalyst-modified corrugated cigarette paper wrapper comprises a
fibrous web, an optional web-filler material supported by the
fibrous web, and catalyst particles supported by the fibrous web
and/or the web-filler material.
2. The cigarette of claim 1, wherein the catalyst-modified
corrugated cigarette paper wrapper comprises a plurality of
channels that run axially along the length of the cigarette; and/or
is formed around a gas permeable inner wrapper.
3. The cigarette of claim 1, wherein the catalyst-modified
corrugated cigarette paper wrapper is wrapped by a non-corrugated
paper wrapper together forming a composite wrapper.
4. The cigarette of claim 3, wherein the non-corrugated paper
wrapper is substantially free of catalyst particles; or
incorporates catalyst particles on an inner surface of the
non-corrugated paper wrapper in an amount effective for reducing
the concentration of carbon monoxide and/or nitric oxide in
mainstream smoke during smoking of the cigarette.
5. The cigarette of claim 1, wherein the catalyst particles have an
average particle size of less than about 500 nanometer; and/or
comprise a transition metal oxide, a transition metal hydroxide,
and/or a transition metal oxyhydroxide.
6. A catalyst-modified corrugated cigarette paper comprising: a
fibrous web; an optional web-filler material supported by the
fibrous web; and catalyst particles supported by the fibrous web
and/or the web-filler material.
7. The catalyst-modified corrugated cigarette paper of claim 6,
wherein the catalyst particles are coated on an exposed surface of
the catalyst-modified corrugated cigarette paper; and/or are
supported within the fibrous web of the catalyst-modified
corrugated cigarette paper.
8. The catalyst-modified corrugated cigarette paper of claim 6,
wherein the catalyst particles have an average particle size of
less than about 500 nanometers; or less than about 50
nanometers.
9. The catalyst-modified corrugated cigarette paper of claim 6,
wherein the catalyst particles comprise a transition metal oxide, a
transition metal hydroxide, a transition metal oxyhydroxide, iron
oxide, and/or iron hydroxide.
10. The catalyst-modified corrugated cigarette paper of claim 6,
wherein the web filler material is not optional and comprises
calcium carbonate.
11. The catalyst-modified corrugated cigarette paper of claim 6
having corrugations that are uniformly spaced at a distance less
than their height, from peak to valley.
12. The catalyst-modified corrugated cigarette paper of claim 6,
wherein the paper has a permeability of between about 5 and 80
Coresta units.
13. A method of making a cigarette containing a catalyst-modified
corrugated cigarette paper wrapper, the method comprising: (i)
optionally supporting catalyst particles on a web-filler material
to form a catalyst-modified web-filler; (ii) incorporating catalyst
particles and/or catalyst-modified web-filler in the cigarette
paper to form a catalytic cigarette paper; (iii) forming
corrugations in the cigarette paper to form a corrugated cigarette
paper; (iv) providing a cut filler comprising tobacco to a
cigarette-making machine; and (v) placing the corrugated cigarette
paper around the cut filler to form a tobacco rod portion of the
cigarette.
14. The method of claim 13, wherein the corrugated cigarette paper
is a first wrapper and the method further comprises (vi) placing a
non-corrugated second wrapper around the first wrapper; or the
corrugated cigarette paper is a second wrapper and the method
further comprises (vi) placing a first gas permeable wrapper around
the cut filler prior to step (v).
15. The method of claim 14, wherein the second wrapper is free of
catalyst particles; or incorporates catalyst particles on an inner
surface of the second wrapper.
16. The method of claim 13, wherein the catalyst particles comprise
nanoscale particles.
17. A method of manufacturing catalyst-modified corrugated
cigarette paper, the method comprising: (i) forming cigarette
paper; (ii) forming corrugations in the cigarette paper; and (iii)
incorporating catalyst particles with the cigarette paper.
18. The method of claim 17, wherein step (ii) precedes step (iii);
or step (iii) precedes step (ii).
19. The method of claim 17, wherein the incorporating comprises
spraying or printing the catalyst particles on the cigarette
paper.
20. The method of claim 17, wherein the steps of forming cigarette
paper and incorporating catalyst particles in the cigarette paper
comprise: supplying cellulosic material and catalyst particles to a
head box in a forming section of a papermaking machine, the
catalyst particles comprising unsupported catalyst particles and/or
catalyst modified web-filler; depositing an aqueous slurry
including the cellulosic material and the catalyst particles onto
the forming section of the paper-making machine to form a base web
with the catalyst particles distributed therein; and removing water
from the base web so as to form a sheet of catalytic paper.
21. The method of claim 17, wherein the steps of forming cigarette
paper and incorporating catalyst,particles in the cigarette paper
comprise: supplying cellulosic material to a head box in a forming
section of a papermaking machine; depositing an aqueous slurry
including the cellulosic material onto the forming section of the
papermaking machine to form a base web; distributing catalyst
particles on the base web; and removing water from the base web so
as to form a sheet of catalyst-modified paper.
22. The method of claim 17, wherein the catalyst particles are
supported directly on the paper cigarette.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) to U.S. provisional Application No. 60/754,897, filed
on Dec. 30, 2005, the entire content of which is incorporated
herein by reference.
BACKGROUND
[0002] In the description that follows reference is made to certain
structures and methods, however, such references should not
necessarily be construed as an admission that these structures and
methods qualify as prior art under the applicable statutory
provisions. Applicants reserve the right to demonstrate that any of
the referenced subject matter does not constitute prior art.
[0003] Cigarettes produce both mainstream smoke during a puff and
sidestream smoke during static burning. Constituents of both
mainstream smoke and sidestream smoke are carbon monoxide (CO) and
nitric oxide (NO). There is an interest in reducing the
concentration of carbon monoxide and nitric oxide in mainstream and
sidestream smoke.
SUMMARY
[0004] A cigarette comprises a tobacco rod wrapped in a cigarette
wrapper, wherein the cigarette wrapper comprises a
catalyst-modified corrugated cigarette paper wrapper having a
fibrous web, an optional web-filler material supported by the web,
and catalyst particles supported by the web and/or the web-filler
material. Catalyst-modified corrugated cigarette paper comprises a
fibrous web, an optional web-filler material supported by the web,
and catalyst particles supported by the web and/or the web-filler
material.
[0005] The catalyst-modified corrugated cigarette paper wrapper
defines a plurality of channels that run axially along the length
of the cigarette. The corrugations are preferably sized such that
their spacing, peak to valley, is less than their height. A
preferred catalyst-modified corrugated cigarette paper wrapper is a
composite wrapper further comprising a non-corrugated paper wrapper
wrapped around the catalyst-modified corrugated paper wrapper. The
non-corrugated outer wrapper can be substantially free of catalyst
particles or can comprise catalyst particles on an inner surface
thereof. A further preferred composite wrapper comprises a gas
permeable inner wrapper.
[0006] The catalyst particles (e.g., nanoscale catalyst particles)
can be incorporated in the catalyst-modified corrugated cigarette
paper wrapper in an amount effective to reduce the concentration in
mainstream smoke of carbon monoxide and/or nitric oxide during
smoking of a cigarette comprising the wrapper.
[0007] Preferred catalyst particles, which can be coated on an
exposed surface of the paper or supported within the fibrous web of
the paper (e.g., supported on web-filler material such as calcium
carbonate), comprise a transition metal oxide and/or a transition
metal hydroxide such as oxides and/or hydroxides of iron. Preferred
catalyst-modified corrugated cigarette paper has a permeability of
between about 5 and 80 Coresta units.
[0008] A method of making a cigarette comprising a
catalyst-modified corrugated cigarette paper wrapper comprises (i)
optionally supporting catalyst particles on a web-filler material
to form a catalyst-modified web-filler, (ii) incorporating catalyst
particles and/or catalyst-modified web-filler in cigarette paper to
form catalytic cigarette paper, (iii) forming corrugations in
cigarette paper to form a corrugated cigarette paper, (iv)
providing cut filler comprising tobacco to a cigarette making
machine, and (v) placing the corrugated cigarette paper around the
cut filler to form a tobacco rod portion of the cigarette.
Optionally, a non-corrugated second wrapper can be placed around
the catalyst-modified corrugated cigarette paper wrapper. The
non-corrugated second wrapper can be free of catalyst particles or
can have catalyst particles incorporated on an inner surface
thereof. In a further embodiment, a gas permeable inner wrapper can
be formed around the cut filler prior to forming the
catalyst-modified corrugated cigarette paper wrapper around the cut
filler.
[0009] A method of manufacturing catalyst-modified corrugated
cigarette paper comprises (i) forming cigarette paper, (ii) forming
corrugations in the cigarette paper, and (iii) incorporating
catalyst particles in the cigarette paper. The steps of forming
corrugations in the paper and incorporating catalyst particles in
the paper can be performed in either order.
[0010] A first preferred method of manufacturing catalyst-modified
corrugated cigarette paper comprises supplying cellulosic material
and catalyst particles to a head box in a forming section of a
papermaking machine, the catalyst particles comprising unsupported
catalyst particles and/or catalyst modified web-filler; depositing
an aqueous slurry including the cellulosic material and the
catalyst particles onto the forming section of the papermaking
machine to form a base web with the catalyst particles distributed
therein; and removing water from the base web so as to form a sheet
of catalytic paper.
[0011] A second preferred method of manufacturing catalyst-modified
corrugated cigarette paper comprises supplying cellulosic material
to a head box in a forming section of a papermaking machine;
depositing an aqueous slurry including the cellulosic material onto
the forming section of the papermaking machine to form a base web;
distributing catalyst particles on the base web; and removing water
from the base web so as to form a sheet paper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a perspective view of a cigarette comprising a
catalyst-modified corrugated cigarette paper wrapper according to
one embodiment.
[0013] FIG. 2(a) is an axial view of the cigarette of FIG. 1, and
FIG. 2(b) shows a magnified view.
[0014] FIG. 3 shows a cigarette comprising a catalyst-modified
corrugated cigarette paper wrapper and a second outer wrapper.
[0015] FIG. 4(a) shows an axial view of the cigarette of FIG. 3,
and FIG. 4(b) shows a magnified view.
[0016] FIG. 5 shows an axial view of a cigarette comprising a
catalyst-modified corrugated cigarette paper wrapper according to a
further embodiment.
[0017] FIG. 6 is a schematic illustration of a papermaking machine
for making a catalytic cigarette paper.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] A catalyst-modified corrugated cigarette paper wrapper
comprises a fibrous web, an optional web-filler material supported
by the web, and catalyst particles supported by the web and/or the
web-filler material. Catalyst-modified corrugated cigarette paper
can be used to manufacture a cigarette and is typically consumed
during smoking of the cigarette. In cigarettes comprising a
catalyst-modified corrugated paper wrapper, the concentration in
mainstream and sidestream smoke of carbon monoxide and/or nitric
oxide can be reduced.
[0019] In cigarettes comprising catalyst-modified corrugated
cigarette paper wrappers, the catalyst particles can promote the
conversion of carbon monoxide (CO) to carbon dioxide (CO.sub.2) via
catalysis and/or oxidation mechanisms. As an example, the catalyst
particles can promote the oxidation of carbon monoxide by a gaseous
source of oxygen according to the reaction
MO.sub.x+2CO+O.sub.2=MO.sub.x+2CO.sub.2, where MO.sub.x represents
a transition metal oxide catalyst, or a mixture of transition metal
oxide catalysts (M=a transition metal such as Ti, V, Cr, Mn, Fe,
Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ce, Ta, W, Re, Os,
Ir, Pt or Au), and x is a positive real number. Further, it is
believed that subsequent to the catalytic reaction, the catalyst
particles can oxidize carbon monoxide by donating an oxygen atom to
a carbon monoxide molecule according to the equation
MO.sub.x+CO=MO.sub.x-1+CO.sub.2. The oxidation of CO can proceed in
the presence or absence of a gaseous source of oxygen. In addition
to converting CO to CO.sub.2, the catalyst particles can promote
the conversion of nitric oxide to nitrogen via catalysis and/or
reduction mechanisms.
[0020] The catalyst particles can comprise transition metal oxides
and/or transition metal hydroxides. Exemplary catalyst particles
comprise iron oxide, iron hydroxide and/or iron oxyhydroxide.
Preferred catalyst particles include .alpha.-Fe.sub.2O.sub.3,
.gamma.-Fe.sub.2O.sub.3, FeOOH, and mixtures thereof. For instance,
MACH I, Inc., King of Prussia, PA markets nanoscale particles under
the trade names NANOCAT.RTM. Superfine Iron Oxide (SFIO) and
NANOCAT.RTM. Magnetic Iron Oxide. The NANOCAT.RTM. Superfine Iron
Oxide comprises amorphous ferric oxide (e.g., Fe.sub.2O.sub.3) in
the form of a free-flowing powder with an average particle size of
about 3 nm, a specific surface area of about 250 m.sup.2/g, and a
bulk density of about 0.05 g/cm.sup.3. The Superfine Iron Oxide is
synthesized by a vapor-phase process, which renders it
substantially free of impurities that may be present in
conventional catalysts, and is suitable for use in food, drugs, and
cosmetics. The NANOCAT.RTM. Magnetic Iron Oxide is a free-flowing
powder with a particle size of about 25 nm and a surface area of
about 40 m.sup.2/g. The catalyst particles can have a shape that is
spherical, cubical, and/or acicular.
[0021] Other exemplary catalyst particles comprise ceria-based
catalyst particles. Ceria-based catalyst particles can oxidize CO
at near ambient (i.e., room) temperatures. Suitable ceria-based
catalyst particles are disclosed in commonly-owned U.S. Pat. No.
6,857,431, the entire content of which is herein incorporated by
reference. Still further exemplary catalyst particles comprise
doped metal oxides such as yttria doped with zirconium, manganese
oxide doped with palladium, or mixtures of metal oxides, doped
metal oxides, etc., which are disclosed in commonly-owned U.S.
Patent Publication No. 2003/0131859, the entire content of which is
herein incorporated by reference.
[0022] In a preferred embodiment, the catalyst particles can
comprise nanoscale particles. By "nanoscale" is meant that the
catalyst particles have an average particle size of less than about
500 nanometers, preferably less than about 100 nanometers, most
preferably less than about 10 nanometers. A bulk density of the
catalyst particles is preferably less than about 0.3 g/cm.sup.3,
more preferably less than 0.1 g/cm.sup.3. The Brunauer, Emmett, and
Teller (BET) surface area of preferred catalyst particles is
greater than about 10 m.sup.2/g (e.g., greater than 50,100 or 200
m.sup.2/g).
[0023] The ratio, in weight percent, of web-filler material to
catalyst particles can be any suitable ratio ranging from 0% to
99%. The web-filler material, if provided, can include an oxide,
carbonate or hydroxide of a Group II, Group III or Group IV metal,
or the web-filler material can be selected from the group
consisting of CaCO.sub.3, TiO.sub.2, SiO.sub.2, Al.sub.2O.sub.3,
MgCO.sub.3, MgO, and/or Mg(OH).sub.2. A preferred average particle
size of the web-filler material is from about 0.1 to 10
micrometers, more preferably less than about 2 micrometers.
[0024] A catalyst-modified corrugated cigarette paper wrapper can
increase the firmness and rigidity of a cigarette. Furthermore, a
catalyst-modified corrugated cigarette paper wrapper can increase
the catalytic efficiency of catalyst particles incorporated in the
wrapper.
[0025] An embodiment of a cigarette having a catalyst-modified
corrugated cigarette paper wrapper is shown in FIG. 1. Cigarette
100 has a tobacco rod portion 110 and a filtering tip portion 120.
Optionally, embodiments of the cigarette 100 can be practiced
without a filtering tip. The tobacco rod portion 110 comprises a
column of tobacco 112 that is wrapped with a cigarette paper
wrapper 130. The cigarette paper wrapper 130 preferably comprises a
thin, flexible corrugated layer 140.
[0026] An axial view of cigarette 100 is shown in FIG. 2(a). As
shown in the expanded view in FIG. 2(b), the catalyst-modified
corrugated cigarette paper wrapper 140 includes a web 142 of
fibrous cellulosic material in which is preferably dispersed
particles of web-filler material 144 such as calcium carbonate
(CaCO.sub.3). Incorporated in the catalyst-modified corrugated
paper wrapper 140 are catalyst particles 146. The catalyst
particles 146 can be supported directly on the paper web 142, or in
an alternate embodiment, the catalyst particles can be supported on
particles of the web-filler material 144. The terms "incorporated
in" means that the catalyst particles can be surrounded by the
matrix of cellulosic material (i.e., embedded between fibers of
cellulosic material), or coated on at least one exposed surface of
the paper web.
[0027] The corrugations provide a plurality of channels 150
adjacent to the tobacco column that run axially along the length of
the cigarette. Thus, smoke (e.g., mainstream and/or sidestream
smoke) flowing down the channels can pass over a relatively large
area of the corrugated paper wrapper, and when compared to
non-corrugated wrappers, the smoke can be in contact with a larger
volume of catalyst particles that are incorporated in the
wrapper.
[0028] In practice, the gas permeability (i.e., porosity) of
cigarette paper can be controlled using the web-filler material
144. The permeability is measured in units of Coresta, which is
defined as the volume of air, measured in cubic centimeters, that
passes through one square centimeter of material in one minute at a
pressure gradient of 1 kilopascal.
[0029] The permeability of the catalyst-modified corrugated
cigarette paper wrapper is preferably from about 5 Coresta units to
about 80 Coresta units, and more preferably from about 30 to 35
Coresta units. Other permeabilities of the wrapper can be selected
based on the application and location of the wrapper. Further, the
catalyst-modified corrugated cigarette paper wrapper can have a
basis weight of from about 18 g/m.sup.2 to 60 g/m.sup.2, more
preferably from about 30 g/m.sup.2 to about 45 g/m.sup.2. However,
any suitable basis weight for the corrugated wrapper can be
selected. The paper wrapper can have a thickness of from about 15
to 100 micrometers, more preferably from 20 to 50 micrometers.
[0030] Optionally, the catalyst-modified corrugated cigarette paper
wrapper can comprise a multi-layer (e.g., composite) wrapper.
Additional layers in a multilayer wrapper can be from 0.1 to 10
times the permeability of the first layer, and can have a thickness
of from 0.1 to 2 times the thickness of the first layer. In
embodiments where a composite wrapper is provided (e.g., a
conventional wrapper formed around a catalyst-modified corrugated
cigarette paper wrapper), both the permeability and the thickness
of the inner layer and the outer layer can be selected to achieve a
desired total air permeability and total thickness for the
cigarette.
[0031] A preferred cigarette comprises a composite
catalyst-modified corrugated cigarette paper wrapper. An embodiment
of a cigarette having a composite cigarette paper wrapper is shown
in FIGS. 3 and 4(a)-(b). Cigarette 300 includes a tobacco rod
portion 310 including a tobacco column 312 and a filtering tip
portion 320. Embodiments of the cigarette 300 can be practiced
without a filtering tip. The tobacco rod portion 310 comprises a
column of tobacco 312 wrapped with a composite cigarette paper
wrapper 330. The composite cigarette paper wrapper 330 comprises a
thin, flexible corrugated layer 340 and an outer layer 345 of sheet
material that surrounds the catalyst-modified corrugated cigarette
paper wrapper 340.
[0032] An axial view of the cigarette 300 is shown in FIG. 4(a).
Inner channels 350 are formed between the tobacco column 312 and
the catalyst-modified corrugated cigarette paper 340, and outer
channels 352 are formed between the catalyst-modified corrugated
cigarette paper 340 and the outer layer of sheet material 345. As
in the previous embodiment, compared to a non-corrugated wrapper,
the plurality of channels in the catalyst-modified corrugated
cigarette paper wrapper can increase the contact area between
mainstream and/or sidestream smoke and the catalyst particles
incorporated in the wrapper.
[0033] Because the addition of catalyst particles can discolor
cigarette paper, e.g., a paper wrapper becomes non-white or brown,
in a preferred embodiment, an outer wrapper that is a conventional
color, e.g., white, can be placed around an inner corrugated
wrapper having catalyst particles incorporated therein. The outer
wrapper is preferably not a corrugated wrapper and can be free of
catalyst particles so as to provide a smooth outward appearance to
the cigarette that is not affected by any coloration from the
catalyst particles. Alternatively, catalyst particles can be
incorporated in the outer wrapper. For example, catalyst particles
can be coated on an inner surface of the outer wrapper in order to
minimize discoloration of the outer surface of the outer
wrapper.
[0034] FIG. 4(b) shows an expanded view of the cigarette shown in
FIG. 4(a). The catalyst-modified corrugated cigarette paper wrapper
340 includes a web of fibrous cellulosic material 342 in which is
optionally dispersed particles of web-filler material 344. Catalyst
particles 346 are incorporated in the corrugated wrapper 340, and
the catalyst particles can be supported directly on the paper web
342 or on particles of web-filler material 344, if provided.
[0035] In the embodiment illustrated in FIGS. 3 and 4(a)-(b), the
inner corrugated wrapper and the outer wrapper are preferably
individual wrappers formed in separate papermaking processes and
later wrapped around a column of tobacco cut filler to from a
cigarette tobacco rod. The corrugated inner wrapper, the outer
wrapper or both wrappers can include catalyst particles (or
catalyst-modified web-filler). In examples where catalyst particles
are incorporated in both wrappers, the catalyst composition,
particle shape, size and loading in each wrapper can be the same or
different. Both the inner corrugated wrapper and the outer wrapper
can be selected to give a desired performance with respect to
cigarette properties, such as puff count, tar, burn rate, and ash
appearance. As shown and described, for example, in FIGS. 3 and
4(a)-(b), the preferred embodiments of cigarettes and methods of
making cigarettes include a tobacco rod portion of a cigarette with
a composite wrapper. A preferred composite wrapper comprises an
inner catalyst-modified corrugated cigarette paper wrapper and an
outer wrapper that is substantially free of catalyst particles.
[0036] A composite catalyst-modified corrugated cigarette paper
wrapper can optionally further comprise an inner layer of sheet
material adapted to be formed between the tobacco column and the
corrugated layer. The inner layer, if provided, is preferably
permeable to smoke either by virtue of a relatively porous
structure or by the formation of perforations therethrough. When an
inner layer of sheet material is provided, inner channels are
formed between the inner layer of sheet material and the
catalyst-modified corrugated cigarette paper.
[0037] FIG. 5 shows a cigarette comprising a catalyst-modified
corrugated cigarette paper wrapper having a higher density of
corrugations than the previous embodiments illustrated in FIGS.
1-4. In the embodiment illustrated in FIG. 5, the catalyst-modified
corrugated cigarette paper wrapper 564 comprises corrugations that
bend back upon themselves and form loops, each of which touches the
preceding and the following loop of the corrugation near the
optional outer layer 566 and again near the tobacco column 502. In
this embodiment, the corrugations can be glued or otherwise
attached at least at those points where they contact each other
near the outer and inner circumference of the wrapper. Such a
corrugated wrapper can be made sufficiently flexible for use with
cigarette making machines. By omitting the outer layer 566 of sheet
material, the cigarette can have an outward appearance different
from that of a standard cigarette.
[0038] In each of the aforementioned embodiments, it is
particularly preferred that the catalyst-modified corrugated
cigarette paper wrapper have a thickness that is less than a radius
of the tobacco rod (i.e., such that the wrapper represents 50% or
less of the diameter of a cigarette comprising the wrapper). It is
further preferred that the corrugations be uniformly spaced, peak
to valley, at a distance less than their height, so that a tangent
to their sloping portions, assuming a regular sinusoidal waveform,
makes an angle of less than about 45.degree. (e.g., less than about
40.degree., 35.degree. or 30.degree.) with respect to a radial axis
line of a cigarette comprising the wrapper.
[0039] The axially extending channels defined by the corrugations
in the various embodiments may be either opened or closed and, if
closed, may be closed at the mouth end of the cigarette, filter end
of the cigarette, or both. If the channels are closed, it may be
desirable to perforate the wrapper when dilution is desired.
Closing either the inner channels or the outer channels while
leaving the others open can be accomplished prior to manufacturing
the cigarette.
[0040] In preferred embodiments, the channels are open. If, for
example, flavoring is added to the catalyst-modified corrugated
cigarette paper, smoke and air may be drawn along the open channels
toward the mouth end.
[0041] Catalyst-modified corrugated cigarette paper can be made by
incorporating catalyst particles in corrugated cigarette paper. For
example, a liquid dispersion of catalyst particles can be spray
coated on at least one surface of corrugated paper. Alternatively,
catalyst-modified corrugated cigarette paper can be made by forming
corrugations in catalytic cigarette paper. Catalytic paper
comprises catalyst particles that are incorporated in the paper.
Preferred methods of forming catalytic paper are described herein
below.
[0042] One method of forming the corrugations comprises passing a
sheet of cigarette paper between two grooved or threaded rollers.
The depth and pitch of the corrugations in the paper can be
controlled by the geometry of the forming rollers and the pressure
applied to them. When threaded rollers are used, one such roller
preferably has a right-handed thread and the other such roller
preferably has a left-handed thread, and they are rotated in an
opposite sense so that the paper can be fed between the two
rollers. The number of corrugations can be controlled by varying
the number of grooves or threads on the forming rollers and may
range from about 10 to about 60 per inch. The depth of the
corrugations may range from about 0.01 to 0.1 inch.
[0043] According to preferred methods of forming catalytic
cigarette paper, the catalyst particles can be incorporated into
cigarette paper before, during, or after the
papermaking/corrugation processes. According to a first embodiment,
the catalyst particles can be incorporated within the fibrous web
of the paper by first supporting the catalyst particles on
web-filler material to form a catalyst-modified web-filler and then
incorporating the catalyst-modified web-filler in the paper. In a
preferred example, the catalyst-modified corrugated cigarette paper
can comprise CaCO.sub.3 web-filler or other filler material used in
cigarette paper manufacture and nanoscale iron oxide catalyst
particles that are supported on the web-filler material.
[0044] A catalyst-modified web-filler can be prepared by forming an
aqueous slurry of catalyst particles and web-filler material and
drying the slurry. Other techniques for forming a catalyst-modified
web-filler include precipitating catalyst particles from a solution
onto a web-filler material, or depositing (e.g., via vapor phase
deposition) catalyst particles onto a web-filler material. A
catalyst-modified web filler can be used as all or part of the
web-filler material in the paper-making process.
[0045] Advantageously, the web-filler-supported catalyst particles
such as supported nanoscale catalyst particles can exhibit a
reduced tendency to agglomerate with each other during processing
and a reduced tendency to leech out of the catalytic paper during
or after cigarette paper manufacture.
[0046] According to a second embodiment, the catalyst particles can
be incorporated in a cigarette paper by supporting the catalyst
particles directly on the cellulosic fibers of the paper web.
Catalyst particles can be coated (e.g., curtain coated), sprayed,
or printed on a wet or dry base web. A retention aid can be used to
improve the distribution and adhesion of the catalyst particles. In
a further example, the catalyst-modified corrugated cigarette paper
wrapper comprises nanoscale iron oxide particles that are supported
directly on the paper web.
[0047] The catalyst particles and web-filler material, if provided,
can be incorporated in a cigarette paper using conventional
papermaking processes. Catalyst particles and/or catalyst-modified
web filler can be supplied to the papermaking process as an aqueous
slurry or as a dry powder to be slurried. For example, an aqueous
slurry ("furnish") including the catalyst particles and cellulosic
material can be supplied to a head box of a forming section of a
Fourdrinier papermaking machine. The aqueous slurry can be supplied
to the head box by one or more conduits in fluid communication with
a source, such as a storage tank. Optionally, an aqueous slurry
containing catalyst particles and an aqueous slurry of cellulosic
material without catalyst particles or with a different
concentration or type of catalyst particles can be supplied to
separate head boxes.
[0048] An exemplary method deposits aqueous slurry from a head box
onto a forming section so as to form a base web of cellulosic
material. In a typical Fourdrinier machine, the forming section is
a Fourdrinier wire arranged as an endless forming wire immediately
below the head box. An opening defined in a lower portion of the
head box adjacent to the endless wire permits the aqueous slurry to
flow onto the top surface of the endless wire to form a wet base
web.
[0049] Optionally, the aqueous slurry can be deposited onto a
pre-formed support web that is retained within the paper. For
example, a pre-formed support web can be transported through the
forming section of a papermaking machine and can be a foundation on
which the aqueous slurry is deposited. The aqueous slurry dries and
the paper sheet (e.g., finished web) is formed with
catalyst-modified web-filler or catalyst particles embedded
therein. The support web can be a conventional web, such as a flax
support web, or can include a web with an incorporated catalytic
component. If the support web includes a catalytic component, the
incorporated catalytic component can be supported on a web-filler
material, or can be directly supported on the support web without a
web-filler material.
[0050] After depositing the aqueous slurry onto the forming
section, water is removed from the wet base web, and with
additional processing such as further drying and pressing, if
necessary, forms a sheet of catalytic paper (e.g., finished web).
The catalytic paper can be corrugated in an additional processing
step.
[0051] Referring to FIG. 6, a cigarette papermaking machine 600
includes a head box 602 operatively located at one end of a
Fourdrinier wire 604, and source of feed stock slurry such as a run
tank 606 in communication with the head box 602. The head box 602
can be one typically utilized in the papermaking industry for
laying down cellulosic pulp upon the Fourdrinier wire 604. In the
usual context, the head box 602 is communicated to the run tank 606
through a plurality of conduits. The run tank 606 receives furnish
from a furnish supply 618. Preferably, the feed stock from the run
tank 606 is a refined cellulosic pulp such as a refined flax or a
wood pulp commonly practiced in the cigarette papermaking industry.
Preferably, a chalk tank 628 (containing the catalyst modified
filler described above) is communicated with the run tank 606 so as
to establish a desired "chalk" level in the slurry supplied to the
head box 602.
[0052] The Fourdrinier wire 604 carries the laid slurry pulp (e.g.,
base web) from the head box 602 along a path in the general
direction of arrow A in FIG. 6, whereupon water is allowed to drain
from the pulp through the wire 604 by the influence of gravity and
at some locations with the assistance of vacuum boxes 610, 610',
610'' at various locations along the Fourdrinier wire 604. At some
point along the Fourdrinier wire 604, sufficient water is removed
from the base web to establish what is commonly referred to as a
dry line where the texture of the slurry transforms from one of a
glossy, watery appearance to a surface appearance more
approximating that of the finished base web (but in a wetted
condition, e.g., an intermediate web). At and about the dry line,
the moisture content of the pulp material is approximately 85 to
90%, which may vary depending upon operating conditions and the
like.
[0053] Downstream of the dry line, the intermediate web 612
separates from the Fourdrinier wire 604 at a couch roll 614. From
there, the Fourdrinier wire 604 continues on the return loop of its
endless path. Beyond the couch roll 614, the intermediate web 612
continues on through the remainder of the papermaking system which
further dries and presses the intermediate web 612, and surface
conditions it to a desired final moisture content and texture to
form a paper 620 (e.g., finished web). Such drying apparatus is
well known in the art of papermaking, and may include drying
section 616 including drying felts, vacuum devices, rolls, and/or
presses, applied thermal energy, and the like.
[0054] The cigarette making machine 600 can optionally include more
than one head box and/or more than one Fourdrinier wire with either
separate or common furnish supply. The optional second head box
602', suitably integrated with a run-tank and furnish supply, can
lay slurry pulp onto the slurry pulp laid from the first head box
602 and carried along Fourdrinier wire 604. The second and/or
additional head box can be supplied with catalyst modified web
filler to a desired "chalk" level or can be free of catalyst
modified web-filler, as desired based on the number of layers of
slurry pulp to be deposited and/or the use of the wrapper formed
from the papermaking process.
[0055] The optional second Fourdrinier wire 604', suitably
integrated with a head box 602' laying slurry pulp on the
Fourdrinier wire 604' and draining and drying equipment, can form a
second intermediate web 612'. The second intermediate web 612' can
be separated from the second Fourdrinier wire 604' at a second
couch roll 214' and laid on the first intermediate web 612 from the
Fourdrinier wire 604 to be processed into double layer paper.
Multiple optional Fourdrinier wires can be employed to form
multiple layer paper having any desired number of layers, such as
three, four and so forth, up to ten to twelve layers.
[0056] A method of manufacturing catalyst-modified corrugated
cigarette paper comprises forming cigarette paper, forming
corrugations in the cigarette paper, and incorporating catalyst
particles in the cigarette paper. The step of forming corrugations
in the cigarette paper can precede or follow the step of
incorporating catalyst particles in the cigarette paper.
[0057] A first preferred method of manufacturing catalyst-modified
corrugated cigarette paper comprises supplying cellulosic material
and catalyst particles to a head box in a forming section of a
papermaking machine, the catalyst particles comprising unsupported
catalyst particles and/or catalyst modified web-filler; depositing
an aqueous slurry including the cellulosic material and the
catalyst particles onto the forming section of the papermaking
machine to form a base web with the catalyst particles distributed
therein; and removing water from the base web so as to form a sheet
of catalytic paper.
[0058] A second preferred method of manufacturing catalyst-modified
corrugated cigarette paper comprises supplying cellulosic material
to a head box in a forming section of a papermaking machine;
depositing an aqueous slurry including the cellulosic material onto
the forming section of the papermaking machine to form a base web;
distributing catalyst particles on the base web; and removing water
from the base web so as to form a sheet paper.
[0059] The catalyst-modified corrugated cigarette paper can
comprise a laminated, bi-layer or multilayer catalytic paper.
Examples of bi-layer and multilayer paper are disclosed in
commonly-owned U.S. Pat. No. 5,143,098, the entire content of which
is herein incorporated by reference. In an embodiment of a bi-layer
or multilayer catalytic paper, at least one of a first layer and a
second layer can include the catalyst particles described in
embodiments herein.
[0060] Single layer, bi-layer or multilayer catalyst-modified
corrugated cigarette paper may be made using ordinary paper furnish
such as pulped wood, flax fibers, or any standard cellulosic fiber.
Preferably, flax fibers are used. Different fillers, including
different catalytic fillers such as the catalyst modified
web-filler described herein, or different fibers may be used for
each layer and may be contained in different head boxes. For
example, a first head box can hold the materials for a catalytic
paper and a second head box can hold the materials for a
conventional paper wrapper.
[0061] Additional methods of forming catalyst-modified web-filler
material and methods of incorporating web-filler material and
catalyst-modified web-filler material in cigarette paper are
disclosed in commonly-owned U.S. Patent Publication No.
2005/0051185 and U.S. patent application Ser. No. 10/870,449, the
contents of which are hereby incorporated by reference. Additional
examples of papermaking processes include the method for making
banded smoking article wrappers disclosed in commonly-owned U.S.
Pat. No. 5,342,484, the entire content of which is herein
incorporated by reference, and the method for producing paper
having a plurality of regions of variable basis weight in the cross
direction disclosed in commonly-owned U.S. Pat. Nos. 5,474,095 and
5,997,691, the entire contents of which are herein incorporated by
reference.
[0062] Catalyst-modified corrugated cigarette paper can be used as
a wrapper for conventional cigarettes or non-conventional
cigarettes such as cigarettes for electrical smoking systems
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; 5,499,636 and 5,388,594
or non-traditional types of cigarettes having a fuel rod such as
are described in commonly-assigned U.S. Pat. No. 5,345,951, the
entire contents of which are herein incorporated by reference.
[0063] The catalyst-modified corrugated cigarette paper wrapper is
preferably adapted to surround the cut filler to form a tobacco
rod. In addition to cellulose, the wrapper material can comprise
hemp, kenaf, esparto grass, rice straw and mixtures thereof.
Optional filler materials such as flavor additives and burning
additives can be included.
[0064] 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 1/10inch to about 1/20inch or
even 1/40inch. The lengths of the strands typically 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.).
[0065] Any suitable tobacco mixture may be used for the cut filler.
Examples of suitable types of tobacco materials include flue cured,
Burley, Bright, Maryland or Oriental tobaccos, the 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 can also include tobacco
substitutes.
[0066] A method of making a cigarette comprising a
catalyst-modified corrugated cigarette paper wrapper comprises (i)
optionally supporting catalyst particles on a web-filler material
to form a catalyst-modified web-filler, (ii) incorporating catalyst
particles and/or catalyst-modified web-filler in cigarette paper to
form catalytic cigarette paper, (iii) forming corrugations in
cigarette paper to form a corrugated cigarette paper, (iv)
providing cut filler comprising tobacco to a cigarette making
machine; and (v) placing the corrugated cigarette paper around the
cut filler to form a tobacco rod portion of the cigarette.
[0067] During the smoking of a cigarette, oxygen diffuses into the
cigarette through the lit end and through the paper wrapper, and CO
and NO in mainstream smoke flow axially toward the filter end and
radially out of the cigarette through the paper wrapper. After a
typical 2-second puff, CO and NO are concentrated in the periphery
of the cigarette, i.e., proximate to the cigarette wrapper, in
front of the burn zone. The oxygen concentration is high in the
same region as high CO and NO concentrations due to diffusion of
O.sub.2 into the cigarette. Airflow into the tobacco rod is largest
near the burn zone at the periphery of the cigarette and is
approximately proportional to the gradient of temperature, e.g.,
larger airflow is associated with higher temperature gradients.
[0068] In a typical cigarette, the temperature varies from about
850-900.degree. C. near the periphery of the cigarette at the burn
zone to about 300.degree. C. near the center of the cigarette. The
temperature drops further to near ambient temperature at the filter
end. The temperature gradient at the lit end is very large and
within a few of mm in the axial direction of the burn zone, the
temperature drops from about 900.degree. C. to about 200.degree. C.
Further information on airflow patterns, the formation of
constituents in cigarettes during smoking and smoke formation and
delivery can be found in Richard R. Baker, "Mechanism of Smoke
Formation and Delivery", Recent Advances in Tobacco Science, vol.
6, pp. 184-224, (1980) and Richard R. Baker, "Variation of the Gas
Formation Regions within a Cigarette Combustion Coal during the
Smoking Cycle", Beitrage zur Tabakforschung International, vol. 11,
no. 1, pp. 1-17, (1981), the contents of both are incorporated
herein by reference.
[0069] The loading (e.g., amount), type (e.g., composition, size,
shape, etc.) and distribution (e.g., homogeneous or heterogeneous)
of catalyst particles in the catalyst-modified corrugated cigarette
paper wrapper can be selected as a function of the temperature and
airflow characteristics exhibited in a burning cigarette in order
to adjust, i.e., increase, decrease, minimize or maximize, the
conversion rate of CO to CO.sub.2 and/or the conversion rate of NO
to N.sub.2.
[0070] The catalyst-modified corrugated cigarette paper wrapper can
comprise one or more different kinds of catalyst particles. Low
temperature and even room temperature catalysts can extend the
effective region of the reaction zone for CO to C0.sub.2 and/or NO
to N.sub.2 conversion to any desired length along the
cigarette.
[0071] Catalyst-modified corrugated cigarette paper wrappers can be
selected to operate in a given temperature range or in a plurality
of temperature ranges, and the wrapper can be manufactured such
that certain catalyst particles are incorporated into those
portions of the wrapper that are predicted to coincide with the
appropriate temperature for operation of the catalyst. Methods for
selectively incorporating catalyst particles in different regions
of a cigarette paper web and for incorporating different catalyst
particles in a cigarette paper web are disclosed in co-pending,
commonly-owned U.S. Patent Publication No. 2005/0051185, the
content of which is hereby incorporated by reference.
[0072] Although the catalyst is described as having an operating
temperature, the terminology operating temperature refers to the
preferred temperature for conversion of CO to C0.sub.2 and/or NO to
N.sub.2. The catalyst may convert CO and/or NO outside the
described temperature range, but the conversion rate may be
affected.
[0073] In any of the examples described herein, the catalyst
particles can be distributed homogeneously or non-homogeneously
within a catalyst-modified corrugated cigarette paper wrapper.
[0074] In a preferred embodiment, the catalyst particles are
incorporated in the catalyst paper in an amount effective to
convert at least 25% of carbon monoxide to carbon dioxide and at
least 25% of nitric oxide to nitrogen at a temperature of less than
400.degree. C. More preferably, the catalyst particles can convert
at least 50% of carbon monoxide and at least 50% of nitric oxide at
a temperature of less than 400.degree. C.
[0075] Any of the wrappers, cigarettes or methods described herein
can include additional additives conventionally used in wrappers
for cigarettes. These additives can include, for example, additives
to control the appearance, e.g., color, of the wrapper, additives
to control the burn rate of the wrapper, and/or additives to result
in a desired ash appearance.
[0076] The catalyst-modified corrugated cigarette paper wrapper can
be effective to (1) reduce the concentration in mainstream smoke
and/or sidestream smoke of carbon monoxide and/or nitric oxide; (2)
decrease particle entrainment in mainstream smoke because the
catalyst particles are embedded in or adhered to the wrapper and/or
web-filler; (3) increase the catalytic, oxidative and/or reduction
efficiency of the catalyst particles; and/or (4) increase the
mechanical integrity of the wrapper.
[0077] The terminology "mainstream" smoke refers to the mixture of
gases and particles passing down a tobacco rod and issuing through
the filter end, i.e., the amount of smoke issuing or drawn from the
mouth end of a cigarette during smoking of the cigarette.
Mainstream smoke contains smoke drawn in through both the lighted
region and through the cigarette paper wrapper. "Sidestream" smoke
is the smoke given off by a cigarette between puffs (i.e., during
static burning).
[0078] The terms "comprises" and "comprising" as used herein are
taken to specify the presence of stated features, steps, or
components; but the use of these terms does not preclude the
presence or addition of one or more other features, steps,
components, or groups thereof.
[0079] 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.
[0080] While the invention has been described with reference to
preferred embodiments, it is to be understood that variations and
modifications may be resorted to as will be apparent to those
skilled in the art. Such variations and modifications are to be
considered within the purview and scope of the invention as defined
by the claims appended hereto.
* * * * *