U.S. patent application number 13/095447 was filed with the patent office on 2012-01-05 for degradable filter element for smoking article.
Invention is credited to Paul S. Chapman, Robert L. Oglesby, Dennis Potter, Robert J. Pound, Andries D. Sebastian.
Application Number | 20120000481 13/095447 |
Document ID | / |
Family ID | 44514957 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120000481 |
Kind Code |
A1 |
Potter; Dennis ; et
al. |
January 5, 2012 |
DEGRADABLE FILTER ELEMENT FOR SMOKING ARTICLE
Abstract
A filter material configured for use as a filter element of a
smoking article is provided, the filter material including at least
one segment of fibrous tow having a plurality of superabsorbent
objects dispersed therein, the superabsorbent objects comprising a
starch material. Exemplary starch materials include
naturally-occurring starch, hydroxyalkylated starch, starch esters,
ionically modified starch, oxidized starch, hydrolyzed starch,
plasticized starch, gelatinized starch, grafted starch, crosslinked
starch, transglycosylated starch, starch ethers, and mixtures
thereof, as well as blends of starch with other polymers. Filter
elements and smoking articles, such as cigarettes, that contain the
filter material are also provided. A method of preparing polymer
fibers for use in filter elements is also provided, the method
including adding the starch material to a fiber precursor solution
prior to fiber extrusion or dry-blending the starch material with
the polymer material to be formed into fibers.
Inventors: |
Potter; Dennis;
(Kernersville, NC) ; Oglesby; Robert L.;
(Kernersville, NC) ; Chapman; Paul S.;
(Winston-Salem, NC) ; Sebastian; Andries D.;
(Clemmons, NC) ; Pound; Robert J.; (Kernersville,
NC) |
Family ID: |
44514957 |
Appl. No.: |
13/095447 |
Filed: |
April 27, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61360201 |
Jun 30, 2010 |
|
|
|
Current U.S.
Class: |
131/332 ;
131/331 |
Current CPC
Class: |
A24D 3/14 20130101; A24D
3/068 20130101; A24D 3/10 20130101 |
Class at
Publication: |
131/332 ;
131/331 |
International
Class: |
A24D 3/08 20060101
A24D003/08; A24D 3/06 20060101 A24D003/06 |
Claims
1. A filter material configured for use as part of a smoking
article, comprising: at least one segment of fibrous tow at least
one degradation-enhancing object, the degradation-enhancing object
configured to be activated by contact with moisture in a disposal
environment.
2. The filter material of claim 1, wherein the at least one
degradation-enhancing object comprises a superabsorbent material
configured to volumetrically expand upon contact with moisture and
thereby to exert mechanical force against the fibrous tow.
3. The filter material of claim 2, wherein the superabsorbent
material comprises a material selected from the group consisting of
sodium polyacrylate) polyacrylamide copolymer, ethylene maleic
anhydride copolymer, cross-linked carboxy-methyl-cellulose,
polyvinyl alcohol copolymer, cross-linked polyethylene oxide,
hydrogel, starch-grafted copolymer of polyacrylonitrile,
polyacrylate with poly(ethylene glycol), alginate-poly(sodium
acrylate-coacrylamide), alginate-g-poly(sodium acrylate)/kaolin,
carboxymethylchitosan-g-poly(acrylic acid) copolymer,
copolymerizate of acrylic acid and maleic anhydride,
polyvinylalcohol-phosphate, acrylic acid-polyvinyl alcohol
copolymer, polyacrylamide,
acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethyl carbamoyl)acrylic
acid, poly(acrylamide-co-methyl methacrylate),
polyacrylamide/sodium alginate, polyacrylic acid, poly(sodium
acrylate) cross-linked with modified poly(ethylene glycol),
sulfonated polystyrene, hydrolysed acrylonitrile sulfonated
polystyrene, poly(ethylene oxide), n-vinyl-2-pyrrolidone with
partially neutralized acrylic acid, poly(tartaramide)s,
poly(ester-amide)s with oxyethylene segments, poly(aspartic acid),
poly(aspartic acid) derivative, poly(acrylic
acid)/attapulgite/sodium humate, and any combination thereof.
4. The filter material of claim 2, wherein the superabsorbent
material is configured as a selected one of a capsule, pellet, or
thread.
5. The filter material of claim 2, wherein the superabsorbent
material is configured, dimensioned, and disposed such that
volumetric expansion thereof will spread apart the filter
material.
6. The filter material of claim 1, further comprising at least one
of plug wrap material and tipping material circumscribing the
fibrous tow.
7. The filter material of claim 6, wherein the
degradation-enhancing object is disposed between the fibrous tow
and the circumscribing material.
8. The filter material of claim 1, wherein the fibrous tow
comprises a plurality of individual filaments, and wherein a
plurality of degradation-enhancing objects are disposed between the
individual filaments.
9. The filter material of claim 1, wherein the at least one
degradation-enhancing object comprises a coating.
10. The filter material of claim 9, wherein the coating is
configured to be disruptable by moisture.
11. The filter material of claim 1, wherein the fibrous tow
comprises cellulose acetate tow, polyolefin tow, or a combination
thereof.
12. A filter element for a smoking article comprising one or more
segments of fibrous tow filter material according to claim 1.
13. The filter element of claim 12, comprising a first segment of
fibrous tow filter material and a second segment of fibrous tow
filter material, wherein the first segment of fibrous tow filter
material comprises a superabsorbent material and the second segment
is devoid of superabsorbent material.
14. The filter material of claim 1, further comprising at least one
degradability-promoting feature selected from the group consisting
of microbial agents, cellulase, and fungal agents.
15. A cigarette comprising: a tobacco rod having a smokable filler
material contained within a circumscribing wrapping material and a
filter element connected to the tobacco rod at one end of the
tobacco rod, said filter element comprising at least one segment of
fibrous tow having at least one degradation-enhancing object
disposed therein, the degradation-enhancing object configured to be
activated by contact with water.
16. The cigarette of claim 15, wherein the at least one
degradation-enhancing object comprises a superabsorbent material
configured to volumetrically expand upon contact with moisture and
thereby to exert mechanical force against the fibrous tow
sufficient to disperse the fibrous tow.
17. The cigarette of claim 16, wherein the superabsorbent material
comprises a material selected from the group consisting of sodium
polyacrylate) polyacrylamide copolymer, ethylene maleic anhydride
copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol
copolymer, cross-linked polyethylene oxide, hydrogel,
starch-grafted copolymer of polyacrylonitrile, polyacrylate with
poly(ethylene glycol), alginate-poly(sodium acrylate-coacrylamide),
alginate-g-poly(sodium acrylate)/kaolin,
carboxymethylchitosan-g-poly(acrylic acid) copolymer,
copolymerizate of acrylic acid and maleic anhydride,
polyvinylalcohol-phosphate, acrylic acid-polyvinyl alcohol
copolymer, polyacrylamide,
acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethyl carbamoyl)acrylic
acid, poly(acrylamide-co-methyl methacrylate),
polyacrylamide/sodium alginate, polyacrylic acid, poly(sodium
acrylate) cross-linked with modified poly(ethylene glycol),
sulfonated polystyrene, hydrolysed acrylonitrile sulfonated
polystyrene, poly(ethylene oxide), n-vinyl-2-pyrrolidone with
partially neutralized acrylic acid, poly(tartaramide)s,
poly(ester-amide)s with oxyethylene segments, poly(aspartic acid),
poly(aspartic acid) derivative, poly(acrylic
acid)/attapulgite/sodium humate, and any combination thereof.
18. The cigarette of claim 16, wherein the superabsorbent material
is configured as a selected one of a capsule, pellet, or
thread.
19. The cigarette of claim 16, further comprising at least one of
plug wrap material and tipping material circumscribing the fibrous
tow, and where the mechanical force is sufficient to disrupt the at
least one plug wrap material and/or tipping material.
20. The cigarette of claim 15, wherein the at least one
degradation-enhancing object is disposed in a location selected
from the group consisting of: between fibers of the fibrous tow,
between the fibrous tow and an overlying wrapping material, between
segments of fibrous tow, and any combination thereof.
21. The cigarette of claim 20, wherein the at least one
degradation-enhancing object comprises a coating.
22. The cigarette of claim 21, wherein the coating is configured to
be disruptable by moisture.
23. The cigarette of claim 21, wherein the fibrous tow comprises
cellulose acetate tow, polyolefin tow, or a combination
thereof.
24. A cigarette including a filter configured to degrade at an
enhanced rate in a disposal environment where moisture is
contacted, the cigarette comprising: a tobacco rod circumscribed by
a wrapping material; and a filter attached to the tobacco rod by a
tipping material, the filter comprising: a fibrous tow material
circumscribed by plug wrap material contacting the tipping
material; and at least one superabsorbent degradation-enhancing
object contacting at least one of the tow material, the plug wrap
material, and the tipping material, the object configured to
volumetrically expand upon contact with moisture in a disposal
environment.
25. The cigarette of claim 24, wherein the volumetric expansion of
the object is configured as sufficient to exert mechanical force
against the fibrous tow that will disperse the fibrous tow and
disrupt at least a portion of the plug wrap, the tipping material,
or both the plug wrap and tipping material.
26. The cigarette of claim 24, wherein at least one of the plug
wrap and the tipping paper further comprises a biodegradable
adhesive.
27. A cigarette including a filter configured to degrade at an
enhanced rate in a disposal environment where moisture is
contacted, the cigarette comprising: a tobacco rod circumscribed by
a wrapping material; and a filter attached to the tobacco rod by a
tipping material, the filter comprising: a gathered web filters
made using a selected one of paper, non-woven fabric, or
combination thereof, circumscribed by plug wrap material contacting
the tipping material; and at least one superabsorbent
degradation-enhancing object contacting at least one of the tow
material, the plug wrap material, and the tipping material, the
object configured to volumetrically expand upon contact with
moisture in a disposal environment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application which
claims priority to U.S. provisional application Ser. No.
61/360,201, filed Jun. 30, 2010, which is incorporated by reference
herein in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to products made or derived
from tobacco, or that otherwise incorporate tobacco, and are
intended for human consumption, and in particular, to filters for
cigarettes. The invention is directed to additives for filter
elements configured for increasing the rate of degradation.
BACKGROUND
[0003] Popular smoking articles, such as cigarettes, have a
substantially cylindrical rod-shaped structure and include a
charge, roll or column of smokable material, such as shredded
tobacco (e.g., in cut filler form), surrounded by a paper wrapper,
thereby forming a so-called "smokable rod" or "tobacco rod."
Normally, a cigarette has a cylindrical filter element aligned in
an end-to-end relationship with the tobacco rod. Typically, a
filter element comprises plasticized cellulose acetate tow
circumscribed by a paper material known as "plug wrap." Certain
filter elements can incorporate polyhydric alcohols. Typically, the
filter element is attached to one end of the tobacco rod using a
circumscribing wrapping material known as "tipping paper." It also
has become desirable to perforate the tipping material and plug
wrap, in order to provide dilution of drawn mainstream smoke with
ambient air. Descriptions of cigarettes and the various components
thereof are set forth in Tobacco Production, Chemistry and
Technology, Davis et al. (Eds.) (1999). A cigarette is employed by
a smoker by lighting one end thereof and burning the tobacco rod.
The smoker then receives mainstream smoke into his/her mouth by
drawing on the opposite end (e.g., the filter end) of the
cigarette, until the tobacco rod is partially or completely
consumed, after which the remaining cigarette portion is
discarded.
[0004] The discarded portion of the cigarette rod is primarily
composed of the filter element. In general, cigarette filters
include solvent cross linked cellulose acetate fiber bundles
wrapped in two layers of paper. The first layer of paper, often
referred to as plug wrap, holds the fiber bundle together in a rod
form and may include a glue line to anchor the fiber bundle to the
plug wrap paper; the second layer, often referred to as the
tipping, is fully adhered to the plug wrap and attaches the filter
tube to the wrapping material surrounding the cigarette's tobacco
rod. Cigarette filters are slow to degrade or disperse in the
environment. This is generally attributed to the tightly bound
nature of the filter plug's design which is configured to provide a
specified filtering effect, but which insulates the majority of the
filter from environmental effects upon disposal. Studies have shown
that once the paper layers (e.g., plug wrap and tipping material)
have been fully breached and the cellulose acetate fibers opened
and exposed to environmental effects, the degradation and
dispersion of the filter elements will progress at a much
accelerated rate, rather than taking months or even years to
degrade.
[0005] A number of approaches have been used in the art to promote
an increased rate of degradation of filter elements. One approach
involves incorporation of additives (e.g., water soluble cellulose
materials, water soluble fiber bonding agents, photoactive
pigments, or phosphoric acid) into the cellulose acetate material
in order to accelerate polymer decomposition. See U.S. Pat. No.
5,913,311 to Ito et al.; U.S. Pat. No. 5,947,126 to Wilson et al.;
U.S. Pat. No. 5,970,988 to Buchanan et al.; and U.S. Pat. No.
6,571,802 to Yamashita. In some cases, conventional cellulose
acetate has been replaced with other materials, such as moisture
disintegrative sheet materials, extruded starch materials, or
polyvinyl alcohol. See U.S. Pat. No. 5,709,227 to Arzonico et al;
U.S. Pat. No. 5,911,224 to Berger; U.S. Pat. No. 6,062,228 to
Loercks et al.; and U.S. Pat. No. 6,595,217 to Case et al.
Incorporation of slits into a filter element has been proposed for
enhancing biodegradability, such as described in U.S. Pat. No.
5,947,126 to Wilson et al. and U.S. Pat. No. 7,435,208 to
Garthaffner. U.S. Pat. No. 5,453,144 to Kauffman et al. describes
use of a water sensitive hot melt adhesive to adhere the plug wrap
in order to enhance biodegradability of the filter element upon
exposure to water. U.S. Pat. No. 6,344,239 to Asai et al. proposes
to replace conventional cellulose acetate filter elements with a
filter element comprising a core of a fibrous or particulate
cellulose material coated with a cellulose ester to enhance
biodegradability. Each of these references is incorporated herein
by reference.
[0006] There remains a need in the art for a smoking article filter
exhibiting enhanced environmental degradation properties,
particularly where the filter can be manufactured with only minor
modification of conventional filter rod production equipment.
BRIEF SUMMARY
[0007] Embodiments of the present invention relate to a smoking
article and associated methods, and in particular, a rod-shaped
smoking article (e.g., a cigarette). The smoking article includes a
lighting end (i.e., an upstream end) and a mouth end (i.e., a
downstream end). A mouth end piece is located at the extreme mouth
end of the smoking article, and the mouth end piece allows the
smoking article to be placed in the mouth of the smoker to be drawn
upon. The mouth end piece has the form of a filter element
comprising a fibrous tow filter material. The fibrous tow filter
material may incorporate an effective amount of a degradable starch
material (or other degradable polymer material) configured for
increasing the rate of degradation of the filter material upon
disposal. Dispersal of a degradable material throughout the fibrous
tow can enhance degradation by creating voids within the fibrous
tow as the degradable material decomposes, thus increasing
available surface area within the fibrous tow for contact with the
environment.
[0008] In one aspect, the invention provides a filter material
configured for use as a filter element of a smoking article,
comprising at least one segment of fibrous tow (e.g., cellulose
acetate tow or polyolefin tow, or a combination thereof) including
at least one (up to and potentially including a plurality of)
superabsorbent object(s) dispersed therein (including being
disposed within or between individual fibers of the filter
material), the superabsorbent object comprising a superabsorbent
material, the volume of which increases when it is exposed to water
or other liquid. Exemplary superabsorbent materials may include one
or more of polyacrylic acid sodium salt (a/k/a sodium
polyacrylate), polyacrylamide copolymer, ethylene maleic anhydride
copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol
copolymers, cross-linked polyethylene oxide, various hydrogels, and
starch-grafted copolymer of polyacrylonitrile, or any other
suitable superabsorbent polymer or non-polymeric material that will
volumetrically expand upon contact with material, such as--for
example--water, that may commonly be located in cigarette filter
disposal locations, and mixtures thereof.
[0009] The invention also provides filter elements for smoking
articles such as cigarettes, wherein the filter element comprises
one or more segments of fibrous tow filter material as described
herein. For example, the filter element can comprise a first
segment of fibrous tow filter material and a second segment of
fibrous tow filter material, wherein the first segment of fibrous
tow filter material comprises a superabsorbent material as
described herein and the second segment is devoid of superabsorbent
material.
[0010] In another aspect, the invention provides a cigarette
comprising a tobacco rod having a smokable filler material
contained within a circumscribing wrapping material and a filter
element connected to the tobacco rod at one end of the tobacco rod,
the filter element comprising at least one segment of fibrous tow
having at least one superabsorbent object dispersed therein.
[0011] In yet another aspect, the invention provides a method of
preparing a cigarette filter having a superabsorbent material
disposed therein. Methods for including a superabsorbent material
into a smoking article filter may include but are not limited to:
capsule insertion technology, pellet insertion technology, thread
insertion technology using a hydrogel or other superabsorbent
polymer or other material formed into a thread/strand or by
adhering grains of hydrogel to a carrier thread, sprinkling of
grains into tow band, and/or inclusion into filter tow with a
plasticizer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In order to assist the understanding of embodiments of the
invention, reference will now be made to the appended drawings,
which are not necessarily drawn to scale. The drawings are
exemplary only, and should not be construed as limiting the
invention.
[0013] FIG. 1 is an exploded perspective view of a smoking article
having the form of a cigarette, showing the smokable material, the
wrapping material components, and the filter element of the
cigarette;
[0014] FIG. 2 is a cross-sectional view of one embodiment of a
filter element;
[0015] FIG. 3 is a cross-sectional view of another embodiment of a
filter element;
[0016] FIG. 4A is a cross-sectional view of another embodiment of a
filter element;
[0017] FIG. 4B is a longitudinal section view of embodiment of FIG.
4A, including internal expanding elements having expanded to
disrupt the filter element and its overlying wrapping layers;
[0018] FIG. 5 is an exploded perspective view of a smoking article
having the form of a cigarette, showing the smokable material, the
wrapping material components, and the filter element of the
cigarette;
[0019] FIG. 5A shows one embodiment of a tipping material with
holes;
[0020] FIG. 5B shows another embodiment of a tipping material with
holes;
[0021] FIGS. 6A and 6B show, respectively, "before" and "after"
images of cigarettes exposed to water, including a control and two
cigarettes embodying aspects of the present invention;
[0022] FIG. 7 shows a longitudinal section view of a cigarette, the
filter of which includes a capsule of a degradation-enhancing
material;
[0023] FIG. 8 shows a longitudinal section view of a cigarette, the
filter of which includes an elongate pellet of a
degradation-enhancing material;
[0024] FIG. 9 shows a longitudinal section view of a cigarette, the
filter of which includes a plurality of capsules;
[0025] FIG. 10 shows a longitudinal section view of a cigarette,
the filter of which includes a rod of a degradation-enhancing
material; and
[0026] FIG. 11 shows a longitudinal section view of a cigarette,
the filter of which includes a plurality of threads of a
degradation-enhancing material.
DETAILED DESCRIPTION
[0027] Embodiments of the invention are described with reference to
the drawings in which like elements are generally referred to by
like numerals. The relationship and functioning of the various
elements of this invention may be better understood by reference to
the following detailed description. However, the embodiments of
this invention are not limited to the embodiments illustrated in
the drawings. It should be understood that the drawings are not
necessarily to scale, and in certain instances details may have
been omitted which are not necessary for an understanding of the
present invention, such as conventional fabrication and assembly.
As used in this specification and the claims, the singular forms
"a," "an," and "the" include plural referents unless the context
clearly dictates otherwise.
[0028] As shown in FIG. 1, a smoking article 100 may be embodied as
a cigarette. The cigarette 100 includes a generally cylindrical rod
102 of a charge or roll of smokable filler material contained in a
circumscribing wrapping material 106. The rod 102 is conventionally
referred to as a "tobacco rod." The ends of the tobacco rod 102 are
open to expose the smokable filler material. The cigarette 100 is
shown as having one optional band 122 (e.g., a printed coating
including a film-forming agent, such as starch, ethylcellulose, or
sodium alginate) applied to the wrapping material 106, and that
band circumscribes the cigarette rod in a direction transverse to
the longitudinal axis of the cigarette. That is, the band 122
provides a cross-directional region relative to the longitudinal
axis of the cigarette. The band 122 can be printed on the inner
surface of the wrapping material (i.e., facing the smokable filler
material), or less preferably, on the outer surface of the wrapping
material. Although the cigarette can possess a wrapping material
having one optional band, the cigarette also can possess wrapping
material having further optional spaced bands numbering two, three,
or more.
[0029] A filter element 126 is disposed at the mouth end 120 of the
tobacco rod 102, and the lighting end 118 is positioned at the
opposite end. The filter element 126 is axially aligned in an
end-to-end relationship with and preferably abutting the tobacco
rod 102. Filter element 126 may have a generally cylindrical shape,
and its diameter may be substantially the same as the diameter of
the tobacco rod. The proximal and distal ends 126a, 126b
(respectively) of the filter element 126 preferably permit the
passage of air and smoke therethrough.
[0030] One exemplary filter element 126 configuration is shown in
longitudinal section in FIG. 2. The filter includes a first filter
segment 232 that is positioned immediately adjacent one end of the
tobacco rod 102. The first filter segment 232 includes filter
material 240 (e.g., cellulose acetate tow impregnated with
plasticizer, such as triacetin). A plurality of
degradation-enhancing objects (e.g., expandable members), here
embodied as superabsorbent objects 250, is disposed within the
filter material 240 of the first segment. If desired, the filter
element may also incorporate other components that have the ability
to alter the properties of the mainstream smoke that passes
throughout the filter element, such as adsorbent materials or
flavorants. Exemplary adsorbent materials include activated carbon
and ion exchange resins, and exemplary flavorants include
flavorant-containing capsules and solid botanical additives such as
peppermint or spearmint leaves or other plant-based flavorants in
particulate form. See, for example, U.S. Pat. No. 6,041,790 to
Smith et al. and U.S. Pat. Application Publication Nos.
2004/0237984 to Figlar et al.; 2005/0268925 to Schluter et al.;
2006/0130861 to Luan et al.; and 2006/0174899 to Luan et al., each
of which is incorporated herein by reference.
[0031] Exemplary superabsorbent materials included sodium
(polyacrylate) polyacrylamide copolymer, ethylene maleic anhydride
copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol
copolymers, cross-linked polyethylene oxide, various hydrogels
including so-called "hydrogel crystals," and starch-grafted
copolymer of polyacrylonitrile, or any other suitable
superabsorbent polymer or non-polymeric material. Preferred
superabsorbent materials will volumetrically expand upon contact
with material, such as--for example--water, that may commonly be
located in cigarette filter disposal locations. Volumetric
expansion of preferred superabsorbent materials will preferably be
by a multiplicative factor of at least two, but volumetric
expansion of preferred materials may be about 6.times. to about
8.times. or greater. In a typical disposal situation where a filter
is properly disposed of into a receptacle and makes its way into a
landfill, contact with moisture such as water or other materials in
a typical waste-disposal site will allow and enable the volumetric
expansion. Then, the volumetric expansion will disrupt and spread
apart the filter fibers, and will also break open the plug wrap 128
and tipping material 146, each of which is configured as a paper or
paper-like material subject to ripping, tearing, bursting, and/or
other disruption when subjected to mechanical force--particularly
in the presence of moisture. (see, e.g. FIG. 4B).
[0032] Other examples of materials useful to form or be included in
(alone, or in combination with other materials) absorbent/expanding
filter inserts include polyacrylate with poly(ethylene glycol),
alginate-poly(sodium acrylate-coacrylamide), alginate-g-poly(sodium
acrylate)/kaolin, carboxymethylchitosan-g-poly(acrylic acid)
copolymer, acrylic acid and maleic anhydride-copolymerizate,
polyvinylalcohol-phosphate, acrylic acid-polyvinyl alcohol
copolymer, polyacrylamide,
acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethyl carbamoyl)acrylic
acid, poly(acrylamide-co-methyl methacrylate),
polyacrylamide/sodium alginate, polyacrylic acid, poly(sodium
acrylate) cross-linked with modified poly(ethylene glycol),
sulfonated polystyrene, hydrolysed acrylonitrile sulfonated
polystyrene, poly(ethylene oxide), n-vinyl-2-pyrrolidone and
partially neutralized acrylic acid, poly(tartaramide)s,
poly(ester-amide)s containing oxyethylene segments, poly(aspartic
acid) and its derivatives, and/or poly(acrylic
acid)/attapulgite/sodium humate.
[0033] All of these disruptive actions combine to allow for easier
dispersal and degradation of the filter material. Certain microbes,
including various bacteria and fungi are known to degrade
superabsorbent polymers, which--when provided in certain
embodiments--may also assist in the degradation of a disposed
filter. For example, certain strains of the fungus Trichoderma
reesei have the ability to secrete large quantities of cellulotic
(e.g., cellulase and hemicellulase) enzymes. Some cellulase enzymes
may break down cellulose components into water-soluble sugars
including, for example, glucose. As another example, the white rot
fungus Phanerochaete chrysosporium is known to biodegrade
polyacrylates and polyacrylate/polyacryalamide copolymers. (see,
e.g.,
[0034] Biodegradation of Superabsorbent polymers in soil, James
Stahl et al, Environ. Sci. & Pollut., Research 7(2) 83-88
(2000)). As another example, starch-grafted-polyacrylonitrile
superabsorbent polymers have been shown to be biodegraded by
naturally occurring, gram-positive cocco-bacillary rod shaped
bacterial cultures (see, e.g., Microbial degradation of
Superabsorbent HSPAN Gel by an Indigenously Isolated Bacterial
Culture, Gosavi et al, Macromolecules, 1999, 32 (13) PP 4264-4271).
One or more of these may be provided.
[0035] Although it is not desirable or preferred, some cigarette
filters are disposed of by being flushed into water disposal lines
or by being left in an open/exposed environment. In these and other
disposal circumstances, the volumetric expansion facilitated in
embodiments described herein will also hasten the degradation of
disposed filters by disrupting the filter and thereby increasing
the access of degradation-enhancing environmental components to the
filter elements.
[0036] The term "degradation-enhancing object" should be understood
within the present specification to refer to discrete objects
disposed upon and/or within fibrous filter tow material. These
discrete objects will expand upon contact with moisture in a
disposal environment, and/or that will actively disperse and/or
degrade fibrous filter tow material and that may also actively
disperse and/or degrade material such as plug wrap or tipping paper
around the filter tow. As such, the term excludes materials such as
starches that are taught as being themselves degradable for
enhancing filter degradation without the expansion characteristics
of the presently-disclosed materials.
[0037] The filter 126 may include a second filter segment 236
longitudinally disposed relative to the first segment 232 and
positioned at the mouth end 120 of the cigarette 100. The second
filter segment 236 includes filter material 248 (e.g., cellulose
acetate tow impregnated with plasticizer, such as triacetin). In
the embodiment shown in FIG. 2, the second filter segment 236 does
not include the superabsorbent objects 250; however, such objects
can be present in and/or on all filter segments, if desired. A
filter segment may be considered devoid of the superabsorbent
objects when it includes no more than about 0.5 weight percent of
the superabsorbent objects, based on the total weight of the filter
segment.
[0038] The filter element 126 is circumscribed along its outer
circumferential surface and/or or longitudinal periphery by a layer
of outer plug wrap 128. In the embodiment of FIG. 2, outer plug
wrap 128 overlies each of the first filter segment 232 and the
second filter segment 236, so as to provide a combined, two-segment
filter element. However, it should be appreciated that a
single-segment filter element and/or multi-segment filter elements
having two or more segments (one or more of which includes at least
one superabsorbent objects) may also be made and used within the
scope of the present invention.
[0039] The filter element 126 is attached to the tobacco rod 102
using tipping material 146 (e.g., essentially air impermeable
tipping paper), that circumscribes both the entire length of the
filter element 126 and an adjacent region of the tobacco rod 102.
In certain preferred embodiments, the inner surface of the tipping
material 146 may be fixedly secured to the outer surface of the
plug wrap 128 and the outer surface of the wrapping material 106 of
the tobacco rod using a suitable adhesive, which attaches the
filter element and the tobacco rod to one another.
[0040] A ventilated or air diluted smoking article can be provided
with an optional air dilution means, such as a series of
perforations 130, each of which extend through the tipping material
and plug wrap. The optional perforations 130, shown in FIG. 1, may
be made by various techniques known to those of ordinary skill in
the art, such as laser perforation techniques. Alternatively,
so-called off-line air dilution techniques can be used (e.g.,
through the use of porous paper plug wrap and pre-perforated
tipping paper). For cigarettes that are air diluted or ventilated,
the amount or degree of air dilution or ventilation can vary.
Frequently, the amount of air dilution for an air diluted cigarette
may be greater than about 10 percent, generally may be greater than
about 20 percent, and sometimes is greater than about 40 percent.
The upper level for air dilution for an air diluted cigarette may
be less than about 80 percent, and often is less than about 70
percent. As used herein, the term "air dilution" is the ratio
(expressed as a percentage) of the volume of air drawn through the
air dilution means to the total volume and air and smoke drawn
through the cigarette and exiting the extreme mouth end portion of
the cigarette.
[0041] During use, the smoker typically lights the lighting end 118
of the cigarette 100 using a match or cigarette lighter, whereupon
the smokable material 102 begins to burn. The mouth end 120 of the
cigarette 100 is placed in the lips of the smoker. Thermal
decomposition products (e.g., components of tobacco smoke)
generated by the burning smokable material 102 are drawn through
the cigarette 100, through the filter element 126, and into the
mouth of the smoker. Following use of the cigarette 100, the filter
element 126 and any residual portion of the tobacco rod 102 may be
discarded.
[0042] As described above, the presence of the superabsorbent
objects can increase the rate of degradation of the filter element
126. Expansion of the superabsorbent objects through and pushing
against the surrounding fibrous tow material, plug wrap, and
tipping paper/material will disrupt the tight, typically
water-resistant construction of the filter element 126, allowing
spaces/voids between those components. The voids provide additional
surface area within the filter element 126 for contact with
environmental elements such as moisture and air, which may enhance
the rate of degradation of the filter.
[0043] Other filter element arrangements may be used without
departing from the invention. For example, the filter element could
include more than the two segments set forth in FIG. 2. The filter
element could also include a cavity formed between two filter
material segments. Still further, the filter segment comprising the
dispersed superabsorbent objects and/or other degradation-enhancing
object(s) can be more centrally located within the filter element
with one or more filter segments that do not contain the particles
on each side. Alternatively, all filter segments could include the
superabsorbent objects.
[0044] Another embodiment is shown in FIG. 3, which illustrates a
three-segment filter 326. As shown in FIG. 3, a first filter
segment 331 is disposed immediately adjacent the tobacco rod 102
and held thereto by plug wrap 128 and tipping material 146. The
first segment 331 includes superabsorbent objects 350 disposed at
the interface between the plug wrap 128 and the filter material
240, and preferably configured, like the other objects described
herein, to exert sufficient mechanical force when in contact with
moisture in a disposal environment to disrupt the plug wrap and/or
tipping material, as well as spreading apart the fibers of fibrous
filter tow. A second filter segment 332 is disposed immediately
adjacent the first segment 331, nearer the mouth end. It includes a
plurality of superabsorbent objects embodied as crystal shaped
particles 351 dispersed through the filter material 240.
[0045] FIGS. 4A and 4B depict a two-segment filter 426. As shown in
FIG. 4A, a first filter segment 432 is disposed immediately
adjacent the tobacco rod 102 and held thereto by plug wrap 128 and
tipping material 146. The first segment 432 includes a
superabsorbent object 450 embodied as a first capsule 450. A second
filter segment 436 is disposed adjacent and slightly spaced apart
from the first segment 432, nearer the mouth end. It includes a
superabsorbent object 454 embodied as a second capsule 454
incorporated into the filter material 240. FIG. 4B shows the filter
426 after it has been exposed to moisture or another
instrumentality activating the superabsorbent objects 450, 454.
Those objects have volumetrically expanded, forcing rupturing of
the plug wrap 128 and the tipping material 146. In addition, this
volumetric expansion will have loosened the fibers of the filter
material 240, allowing them to be more easily dispersed and
degraded. In these and/or other embodiments, a
degradation-enhancing object such as superabsorbent object 454 may
also be disposed in a space between filter segments.
[0046] Certain embodiments may include perforation through the
tipping material and/or plug wrap of a cigarette, as is described
with reference to FIG. 5, which shows an exploded view of a
cigarette 500. A cigarette embodiment 500 may be constructed
including a tobacco rod 502, circumscribed by a wrapping material
506. A filter 126 made of acetate tow or other filter material
providing for longitudinal passage of air therethrough may be
circumscribed by plug wrap (not shown separately), which may in
turn be circumscribed by tipping material 546, configured to attach
the filter portion to the tobacco rod portion of the cigarette 500.
As described above, the plug wrap and/or tipping material 546 may
include a circumferential or other pattern (or non-pattern) of
perforations 530 formed mechanically, by laser (which is generally
preferred), or by some other means. In the cigarette embodiment
500, a generally longitudinal plurality of perforations 533 is also
provided. (The perforations are shown as rather large, but--as
noted above--are not necessarily drawn to scale, and may be
different in both relative and absolute size, geometry, and
dimensions).
[0047] The generally longitudinal plurality of perforations 533 may
be formed substantially co-linear with the central longitudinal
axis of the cigarette 500 as shown. However, the generally
longitudinal plurality of perforations 533 may be formed in a wavy
pattern (FIG. 5A), helical pattern (FIG. 5B), or in any other
generally longitudinal orientation that extends from at or near a
distal/ lighting end of the filter portion to, or at least near to
the mouth-end of the filter portion. In still other embodiments,
the perforations 533 may be formed into a pattern such as, for
example, lettering, logo(s), geometric patterns, or other designs.
The perforations preferably are disposed so as to allow materials
overlying the filter material (e.g., plug wrap, tipping material)
more easily to split or otherwise be disrupted when subjected to
mechanical forces from an expanding object in the filter. Filter
materials such acetate tow commonly exhibit a generally
longitudinal orientation or grain, the end(s) of which are exposed
at the generally cylindrical end(s) of the filter. As a result,
moisture entering the exposed end(s) tends to travel longitudinally
through the filter.
[0048] Then, when one or more expandable objects such as fibrous
materials, inserted objects, or other materials placed in or on the
filter (such as--for example--those items discussed elsewhere in
this specification) expand, the mechanical forces of that expansion
are directed toward the circumference of the filter material 526,
such that at least a portion of the mechanical force (generated by
the expansion of the object(s)) is generally transverse to the
wrapping material 546 and (if present) plug wrap, as well as
generally transverse to the longitudinal orientation or grain of
the filter materials. In each of the embodiments described herein,
the expansive forces of the object(s) in the presence of moisture
will promote rupture of the wrapper (e.g., plug wrap, tipping
material) constraining the filter material and/or will promote
separation of the fibrous and other materials forming the filter,
thereby promotion dispersion and degradation of the filter. The
presence of moisture will also promote weakening of the wrapping
around the filter (e.g., plug wrap, tipping material), which may be
aided by the construction of the filter wrapping as in the
perforated embodiments of FIGS. 5-5B and/or by the composition of
the filter wrapping (e.g., providing filter wrapping that provides
desirable qualities for the forces and level of moisture
encountered during manufacture, storage, and use of cigarettes,
while allowing permeation and weakening and/or degradation in the
presence of moisture encountered in a disposal environment).
[0049] The generally longitudinal plurality of perforations 533
provides a "tearable portion" of the filter region. When an
expandable material in the filter is activated and exerts radial
force within and/or against the filter material 526 against the
plug wrap and tipping material 546, the generally longitudinal
plurality of perforations 533 preferably is configured such that
swelling or other volumetric expansion of an inner member of the
filter 526 will tear the plug wrap and tipping material 546
therealong. In this and all embodiments including an expandable
member in and/or on the filter material, it is most preferable that
moisture conditions encountered during normal use will not activate
the expandable member sufficiently to adversely affect
functionality of the filter with regard to air flow, flavor
transmission, and integrity of the filter material and surrounding
plug wrap and/or tipping material.
[0050] In addition to the superabsorbent objects described above,
some cigarette embodiments may include one or more pellets,
particles, threads, rods, and/or other-shaped units of a cellulosic
polymer that swells when exposed to moisture. The degree of
swelling/expansion occasioned by smoking a cigarette so embodied
(e.g., from the mouth of the smoker, from moisture/heat generated
by pyrolysis of the tobacco rod) preferably will not occur during
the consumption of the cigarette in a manner that would adversely
affect functionality of the filter with regard to air flow, flavor
transmission, and integrity of the filter material and surrounding
plug wrap and/or tipping material. Cigarettes according to such an
embodiment may be constructed in any manner as described above with
reference to one or more of FIGS. 2 through 5B, or any other manner
appropriate to provide expansion and disruption of the filter
material. In addition, these and other embodiments of a cigarette
may include an adhesive used to adhere one or more of wrapping
material, tipping material, and plug wrap to each other and/or
themselves, where the adhesive is configured to release (e.g., by
degradation or other mechanism) when exposed to a high level of
moisture.
[0051] During manufacture of typical cigarette filters, two types
of adhesives are commonly used: (1) a hot melt adhesive for gluing
the edges of the plug wrap, and (2) an aqueous dispersion based
adhesive for gluing the tipping paper. Although the physical form
of these adhesives may be different, both types typically include
ethylene vinyl acetate as the main polymeric ingredient. Ethylene
vinyl acetate is not generally considered a readily biodegradable
polymer. In formulating cigarette filters for accelerated
degradability (e.g., by employing structures disclosed herein, or
forming a filter from polymers that have demonstrated accelerated
biodegradability), it may be desirable that the adhesive that holds
the fibers together within the two layers of paper are also
biodegradable. Certain biodegradable adhesives may be used in
cigarette filters as hot melts and as aqueous dispersions.
[0052] Commercially available biodegradable polymers that can be
used directly as hot melts or used after blending with commonly
used plasticizers and tackifiers include, for example,
thermoplastic starches (e.g., Biograde polymers from Biograde Ltd.,
Biolice polymer from Limgrane, Biomax from DuPont, Bioplast from
Biotec, Cereloy Bio polymer from Cerestech Inc., Getrex polymer
from IGV, Grace Bio GB 100 polymer from Grace Biotech, Mater-Bi
polymers from Novamont, Plantic polymers from Plantic, Re-New
polymers from Starch Tech, Solanyl BP from Rodenburg Biopolymers);
lends of thermoplastic starches and polyolefins (e.g., BioCeres
polymers from FuturaMat, Biograde polymers from Biograde Ltd.,
Cereloy Eco from Cerestech Inc., CP-Bio PP from Cereplast); blends
of thermoplastic starches and polyvinyl alcohol (e.g., Biograde WS
from Biograde); blends of thermoplastic starches and biodegradable
aliphatic polyesters (e.g., Biopar polymers from BiOP Polymer
Technologies, Bioplast polymers from Biotec); and/or blends of
thermoplastic starch and polylactic acid (e.g., CP-EXC, CP-INJ, and
CP-TH series from Cereplast). Biodegradable polymers that may be
applied as aqueous dispersions can be used as tipping glue after
converting them to dispersions by one or more of several
methods.
[0053] With a solvent-antisolvent approach, the polymer is first
dissolved in a water miscible organic solvent. The precipitation of
the polymer into dispersion is induced by mixing the solution with
water. Another approach includes evaporative precipitation in to a
dispersion, where the polymer is dissolved in an organic solvent
which is not miscible with water, and the polymer solution is then
sprayed into heated water resulting in an immediate evaporation of
the organic solvent, which immediately forms the polymer particles
are formed into a dispersion. During a wet ball milling process,
micronized powder of the polymer is charged in to ball mill
containing milling media (e.g., zirconium dioxide beads, silicium
nitride beads, polystyrene beads) with an aqueous stabilizer, which
is typically a surfactant. The moving milling media generates high
shear forces and causes attrition of the original polymer particles
to form a dispersion. High pressure homogenization is a process
performed at room temperature with a piston gap homogenizer in an
aqueous medium. During this process, a coarse suspension is formed
through a very tiny homogenization gap. The particle size reduction
to a dispersion is caused by cavitation forces, shear forces, and
particle collision. During a microfluidics particle size reduction
method, the polymeric material is subjected to ultra high shear
forces to break down to smaller sizes that can be dispersed in
water and stabilized with a surfactant. Another method uses
supercritical fluid technology where a supercritical fluid such as
CO2 is used to effect a particle size reduction of the starting
polymer that can then be dispersed into aqueous media. During a
spray drying process, the polymer is first spray dried to obtain a
powder and then dispersed and stabilized in water with a
surfactant. These or other methods may be used to apply one or more
of the biodegradable adhesives noted herein, or other adhesive(s)
to secure tipping paper and/or plug wrap. The tipping paper and/or
plug wrap thus secured will be more easily released to expose
underlying filter materials to biodegradation or other degradation
processes.
[0054] In addition to the filter-disrupting elements described
herein, some embodiments may include other degradability/
biodegradability features such as disposition of one or more
non-hazardous agents, distinct from the degradation-enhancing
objects of the present specification. These other features (e.g.,
microbial agents, cellulase and/or other enzymatic agents) may be
selected for being non-hazardous and for being able to lie dormant
during normal storage, transport, and--optionally--smoking
conditions, then activated to propagate and consume one or more of
the materials forming the cigarette (e.g., filter tow, other filter
material, plug wrap, tipping material, wrapping material) when
exposed to moisture.
[0055] FIGS. 6A-6B illustrate a comparative example using a
standard cigarette 680 (a Camel.RTM. Wide), a first
capsule-containing cigarette embodiment 660, and a second
capsule-containing cigarette embodiment 670 (also Camel.RTM. Wide
cigarettes). The cigarettes are substantially alike in all aspects,
except that the first and second capsule-containing embodiments
660, 670 each have a superabsorbent capsule 665 (not visible in
FIG. 6A) inserted into the filter tow 692 making up the filter,
with care having been exercised not to disrupt the tipping material
693 encircling the filter tow 692. (It is expected that--in
longitudinal section--these cigarettes, before smoking, would
appear substantially similar to those shown in FIG. 7). The capsule
used was a commercially available water-storing gel bead (JRM
Chemical, Inc. of Cleveland, Ohio). All three cigarettes 660, 670,
680 were smoked under the same standard conditions for about the
same amount of time. Then they were substantially simultaneously
placed into a container 695 of water. After about 10 minutes, as
shown in FIG. 6A, one of the capsule-containing embodiments 670
already showed signs of the tipping paper 693 starting to open
along its seam 694, but the "control cigarette" 680 shows no sign
of change.
[0056] After about 30 minutes, as shown in FIG. 6B (where the
cigarettes are rotated to more clearly show the effect), the
tipping paper 693 of each of the capsule-containing embodiments
660, 670 is substantially open along its seam, but the "control
cigarette" 680 still shows no sign of change along its seam. After
this time, the standard cigarette 680 was substantially unaffected
other than having gotten wet, while the superabsorbent capsule 665
of the first and second capsule-containing embodiments 660, 670
have volumetrically expanded so much that they have split open the
tipping paper seams 694 and started spreading out the filter tow
692. As shown in FIG. 6B, the wrapping material overlying the
filter tow 692 of both of the capsule-containing cigarettes 660,
670 was disrupted from within by the mechanical forces exerted by
volumetric expansion of the capsule therein. As a result, the
filter tow is already being spread apart such that it may more
readily be dispersed and/or degraded. Over a longer time, the
expansion will increase, and--in many disposal environments--the
filter tow of cigarettes equipped with such a
volumetrically-expanding degradation-enhancing element will
disperse in a far more rapid time than would the filter material of
the standard cigarette.
[0057] The splitting at seam 694 in this and other embodiments may
be enhanced by use of a water-soluble (or at least water-sensitive
or water-degradable) adhesive along the plug wrap seam 694.
Examples of appropriate adhesives include those described in U.S.
Pat. Nos. 5,453,144 and 5,498,224 to Kauffman et al. and U.S. Pat.
No. 5,709,227 to Arzonico et al., each of which is incorporated by
reference herein.
[0058] FIG. 7 shows a cigarette 710 including a one-segment filter
726. The material 740 (e.g., acetate tow or other appropriate
material) making up the filter 726 surrounds a capsule 750 of a
degradation-enhancing material such as, for example, a compound
configured to volumetrically expand upon contacting moisture. The
filter material 740 may be encompassed by plug wrap 728 and tipping
material 746, and be attached to a wrapping material-encompassed
tobacco rod 702.
[0059] FIG. 8 shows a cigarette 810 including a one-segment filter
826. The material 840 (e.g., acetate tow or other appropriate
material) making up the filter 826 surrounds an elongate pellet 850
of a degradation-enhancing material such as, for example, a
compound configured to volumetrically expand upon contacting
moisture. The filter material 840 may be encompassed by plug wrap
828 and tipping material 846, and be attached to a wrapping
material-encompassed tobacco rod 802.
[0060] FIG. 9 shows a cigarette 910 including a one-segment filter
926. The material 940 (e.g., acetate tow or other appropriate
material) making up the filter 926 surrounds a trio of capsules 950
of a degradation-enhancing material such as, for example, a
compound configured to volumetrically expand upon contacting
moisture. The filter material 940 may be encompassed by plug wrap
928 and tipping material 946, and be attached to a wrapping
material-encompassed tobacco rod 902.
[0061] FIG. 10 shows a cigarette 1010 including a one-segment
filter 1026. The material 1040 (e.g., acetate tow or other
appropriate material) making up the filter 1026 generally encircles
a rod 1050 of a degradation-enhancing material such as, for
example, a compound configured to volumetrically expand upon
contacting moisture. The filter material 1040 may be encompassed by
plug wrap 1028 and tipping material 1046, and be attached to a
wrapping material-encompassed tobacco rod 1002.
[0062] FIG. 11 shows a three-segment filter 1126 of a cigarette.
The material 1140 (e.g., acetate tow or other appropriate material)
making up the central segment of the filter 1126 surrounds a
plurality of threads 1150 of a degradation-enhancing material such
as, for example, a compound configured to volumetrically expand
upon contacting moisture and/or another material as described
herein. The filter material 1140 may be encompassed by plug wrap
1128 and tipping material 1146, and be attached to a wrapping
material-encompassed tobacco rod.
[0063] Each of the embodiments included herein may include a
coating around the expandable/ expanding objects and/or
degradability-enhancing features, where the coating is configured
to protect the coated feature from moisture for a certain amount of
time and/or moisture-volume exposure. Moisture-soluble and moisture
disruptable coatings are well-known in the confectionary and
pharmaceutical arts. As one example, a thin gelatin coating may be
used to coat the expandable and/or other degradation-enhancing
features in a cigarette filter, where the thin gelatin coating will
generally withstand moisture levels associated with typical
transport, storage, and use of a cigarette without adversely
affecting the cigarette, but will be dissolved or otherwise
disrupted upon contact with a level of moisture encountered in a
disposal environment thereby exposing the coated feature and
allowing its activation.
[0064] The dimensions of a representative cigarette 100 may vary.
Preferred cigarettes are rod-shaped, and can have diameters of
about 7.5 mm (e.g., circumferences of about 20 mm to about 27 mm,
often about 22.5 mm to about 25 mm); and can have total lengths of
about 70 mm to about 120 mm, often about 80 mm to about 100 mm. The
length of the filter element 30 can vary. Typical filter elements
can have total lengths of about 15 mm to about 40 mm, often about
20 mm to about 35 mm. For a typical dual-segment filter element,
the downstream or mouth end filter segment often has a length of
about 10 mm to about 20 mm; and the upstream or tobacco rod end
filter segment often has a length of about 10 mm to about 20
mm.
[0065] Various types of cigarette components, including tobacco
types, tobacco blends, top dressing and casing materials, blend
packing densities and types of paper wrapping materials for tobacco
rods, can be employed. See, for example, the various representative
types of cigarette components, as well as the various cigarette
designs, formats, configurations and characteristics, that are set
forth in Johnson, Development of Cigarette Components to Meet
Industry Needs, 52nd T.S.R.C. (September, 1998); U.S. Pat. No.
5,101,839 to Jakob et al.; U.S. Pat. No. 5,159,944 to Arzonico et
al.; U.S. Pat. No. 5,220,930 to Gentry and U.S. Pat. No. 6,779,530
to Kraker; U.S. Pat. Publication Nos. 2005/0016556 to Ashcraft et
al.; 2005/0066986 to Nestor et al.; 2005/0076929 to Fitzgerald et
al.; 2006/0272655 to Thomas et al.; 2007/0056600 to Coleman, III et
al.; and 2007/0246055 to Oglesby, each of which is incorporated
herein by reference. Most preferably, the entire smokable rod is
composed of smokable material (e.g., tobacco cut filler) and a
layer of circumscribing outer wrapping material.
[0066] The filter material can vary, and can be any material of the
type that can be employed for providing a tobacco smoke filter for
cigarettes. Preferably a traditional cigarette filter material is
used, such as cellulose acetate tow, gathered cellulose acetate
web, polypropylene tow, gathered cellulose acetate web, gathered
paper, strands of reconstituted tobacco, or the like. This may
include gathered web filters using paper and/or one or more
non-woven fabrics. Especially preferred is filamentary or fibrous
tow such as cellulose acetate, polyolefins such as polypropylene,
or the like. One filter material that can provide a suitable filter
rod is cellulose acetate tow having 3 denier per filament and
40,000 total denier. As another example, cellulose acetate tow
having 3 denier per filament and 35,000 total denier can provide a
suitable filter rod. As another example, cellulose acetate tow
having 8 denier per filament and 40,000 total denier can provide a
suitable filter rod. For further examples, see the types of filter
materials set forth in U.S. Pat. No. 3,424,172 to Neurath; U.S.
Pat. No. 4,811,745 to Cohen et al.; U.S. Pat. No. 4,925,602 to Hill
et al.; U.S. Pat. No. 5,225,277 to Takegawa et al. and U.S. Pat.
No. 5,271,419 to Arzonico et al.; each of which is incorporated
herein by reference.
[0067] Normally a plasticizer such as triacetin or carbowax is
applied to the filamentary tow in traditional amounts using known
techniques. In one embodiment, the plasticizer component of the
filter material comprises triacetin and carbowax in a 1:1 ratio by
weight. The total amount of plasticizer is generally about 4 to
about 20 percent by weight, preferably about 6 to about 12 percent
by weight. Other suitable materials or additives used in connection
with the construction of the filter element will be readily
apparent to those skilled in the art of cigarette filter design and
manufacture. See, for example, U.S. Pat. No. 5,387,285 to Rivers,
which is incorporated herein by reference.
[0068] Filamentary tow, such as cellulose acetate, is processed
using a conventional filter tow processing unit such as a
commercially available E-60 supplied by Arjay Equipment Corp.,
Winston-Salem, N.C. Other types of commercially available tow
processing equipment, as are known to those of ordinary skill in
the art, may similarly be used.
[0069] As illustrated in FIG. 2 and some other figures, the filter
elements disclosed herein may include a plurality of
longitudinally-extending segments. Each segment can have varying
properties and may include various materials capable of filtration
or adsorption of particulate matter and/or vapor phase compounds.
Typically, a filter element of the invention will include 1 to 6
segments, and frequently may include 2 to 4 segments. In preferred
embodiments, the degradation-enhancing objects such as, for
example--superabsorbent objects, will not be disposed in the
tobacco rod.
[0070] In addition to degradation-enhancing objects (e.g.,
superabsorbent objects) the filter may include materials
constructed to speed or otherwise facilitate breakdown of the
filter. These materials (which are distinct from the
degradation-enhancing objects) can be made of any filler material
that is itself degradable, meaning the material is capable of
undergoing degradation or decomposition, for example through
chemical reaction that breaks down the particles into decomposition
products, particularly under environmental conditions associated
with disposal of the filter material. One exemplary type of
degradation is biodegradation. As used herein, the term
"biodegradable particle" refers to a particulate material that
degrades under aerobic and/or anaerobic conditions in the presence
of bacteria, fungi, algae, and other microorganisms to carbon
dioxide/methane, water and biomass, although materials containing
heteroatoms can also yield other products such as ammonia or sulfur
dioxide. "Biomass" generally refers to the portion of the
metabolized materials incorporated into the cellular structure of
the organisms present or converted to humus fractions
indistinguishable from material of biological origin.
[0071] Biodegradability can be measured, for example, by placing a
sample in environmental conditions expected to lead to
decomposition, such as placing a sample in water, a
microbe-containing solution, a compost material, or soil. The
degree of degradation can be characterized by weight loss of the
sample over a given period of exposure to the environmental
conditions. Exemplary rates of degradation for certain filter
element embodiments of the invention include a weight loss of at
least about 20% after burial in soil for 60 days or a weight loss
of at least about 30% after 15 days of exposure to a typical
municipal composter. However, rates of biodegradation can vary
widely depending on the type of degradable particles used, the
remaining composition of the filter element, and the environmental
conditions associated with the degradation test. U.S. Pat. No.
5,970,988 to Buchanan et al. and U.S. Pat. No. 6,571,802 to
Yamashita provide exemplary test conditions for degradation
testing.
[0072] Exemplary biodegradable materials include, without
limitation, starch, cellulosic or other organic plant-derived
fibrous materials (e.g., cotton, wool, cedar, hemp, bamboo, kapok,
or flax), polyvinyl alcohol, aliphatic polyesters, aliphatic
polyurethanes, cis-polyisoprene, cis-polybutadiene, polyhydroxy
alkanoates, polyanhydrides, and copolymers and blends thereof. The
term "aliphatic polyester" refers to polymers having the structure
--[C(O)--R--O].sub.n--, wherein n is an integer representing the
number of monomer units in the polymer chain and R is an aliphatic
hydrocarbon, preferably a C1-C10 alkylene, more preferably a C1-C6
alkylene (e.g., methylene, ethylene, propylene, isopropylene,
butylene, isobutylene, and the like), wherein the alkylene group
can be a straight chain or branched. Exemplary aliphatic polyesters
include polyglycolic acid (PGA), polylactic acid (PLA) (e.g.,
poly(L-lactic acid) or poly(DL-lactic acid)), polyhydroxy butyrate
(PHB), polyhydroxy valerate (PHV), polycaprolactone (PCL), and
copolymers thereof. These degradable (including biodegradable)
materials may include, for example, any of the materials described
in pending U.S. patent application Ser. No. 12/539,226, which is
incorporated herein by reference.
[0073] The particle size of the degradable particles (e.g., starch
particles) can vary, but is typically small enough to ensure
uniform dispersion throughout the fibrous tow filter material
without unduly affecting the desirable filtration and mechanical
properties of the fibrous tow. As used herein, reference to
"particles" or "particulate" materials simply refers to discrete
units of relatively small size but does not restrict the
cross-sectional shape or overall geometry of the material, which
can be characterized as spherical, oblong, ovoid, flake-like,
irregular or the like without departing from the invention. The
degradable particles usually have a particle size range of about
100 nm to about 20 microns, more typically about 400 nm to about
800 nm, and most often about 400 nm to about 600 nm. In certain
embodiments, the particle size of the degradable particles can be
characterized as less than about 20 microns, less than about 800
nm, or less than about 600 nm. Certain embodiments of the
degradable particles can be characterized as having a particle size
of more than about 100 nm or more than about 400 nm.
[0074] The amount of degradable particles used in a filter element
can vary, but typical weight percentages are in the range of about
5 to about 30% by weight, based on the overall dry weight of the
filter element, more typically about 10 to about 20% by weight. In
certain embodiments, the amount of degradable particles in the
filter element can be characterized as more than about 5% by
weight, more than about 10% by weight, or more than about 15% by
weight, but less than about 60% by weight, less than about 50% by
weight, or less than about 40% by weight.
[0075] In certain embodiments, the degradable particles (e.g.,
starch particles) are characterized as having certain solubility
properties. For example, in certain applications, it may be
desirable for the particles to have a high degree of solubility in
water. In other embodiments, hydrophobicity (i.e., relatively low
water solubility) will be desired. Many polymer materials,
including starch materials, can be chemically modified in order to
increase or reduce water solubility. In some embodiments, the
particles can be viewed as highly soluble in water. In other
embodiments, the particles have a low level of solubility in water
and/or in certain other solvents, such as solvents used in the
cellulose acetate fiber manufacturing process (e.g., the particles
can be insoluble in acetone). As used herein, the term "soluble"
refers to a material with a solubility in the given solvent of at
least about 50 g/L, typically at least about 75 g/L, and often at
least about 100 g/L at 25.degree. C. A material characterized as
"insoluble" refers to a material having a solubility in the given
solvent of no more than about 5 g/L, typically less than about 2
g/L, and often less than about 0.5 g/L at 25.degree. C.
[0076] The process for making filter elements according to the
invention can vary, but a process for making cellulose acetate
filter elements typically begins with forming cellulose fibers. The
first step in conventional cellulose acetate fiber formation is
esterifying a cellulose material. Cellulose is a polymer formed of
repeating units of anhydroglucose. Each monomer unit has three
hydroxyl groups available for ester substitution (e.g., acetate
substitution). Cellulose esters may be formed by reacting cellulose
with an acid anhydride. To make cellulose acetate, the acid
anhydride is acetic anhydride. Cellulose pulp from wood or cotton
fibers is typically mixed with acetic anhydride and acetic acid in
the presence of an acid catalyst such as sulfuric acid. The
esterification process of cellulose will often result in
essentially complete conversion of the available hydroxyl groups to
ester groups (e.g., an average of about 2.9 ester groups per
anhydroglucose unit). Following esterification, the polymer is
typically hydrolyzed to drop the degree of substitution (DS) to
about 2 to about 2.5 ester groups per anhydroglucose unit. The
resulting product is typically produced in flake form that can be
used in subsequent processing.
[0077] To form a fibrous material, the cellulose acetate flake is
typically dissolved in a solvent (e.g., acetone, methanol,
methylene chloride, or mixtures thereof) to form a viscous
solution. The concentration of cellulose acetate in the solution is
typically about 15 to about 35 percent by weight. Additives such as
whitening agents (e.g., titanium dioxide) can be added to the
solution if desired. The resulting liquid is sometimes referred to
as a liquid "dope."
[0078] The cellulose acetate dope is spun into filaments using a
nonwoven fabric melt-spinning technique. The cellulose acetate dope
is spun into filaments by extruding the liquid dope through a
spinneret. The filaments pass through a curing/drying chamber,
which solidifies the filaments prior to collection. The collected
fibers are combined into a tow band, crimped, and dried.
Conventional crimp ratios are in the range of 1.2 to 1.8. The
fibers are typically packaged in bales that are suitable for later
use in filter element formation processes.
[0079] The process of forming the actual filter element typically
involves mechanically withdrawing the cellulose acetate tow from
the bale and separating the fibers into a ribbon-like band. The tow
band is subjected to a "blooming" process wherein the tow band is
separated into individual fibers. Blooming can be accomplished, for
example, by applying different tensions to adjacent sections of the
tow band or applying pneumatic pressure. The bloomed tow band then
passes through a relaxation zone that allows the fibers to
contract, followed by passage into a bonding station. The bonding
station typically applies a plasticizer such as triacetin to the
bloomed fibers, which softens the fibers and allows adjacent fibers
to fuse together. The bonding process forms a homogenous mass of
fibers with increased rigidity. The bonded tow is then wrapped in
plug wrap and cut into filter rods. Cellulose acetate tow processes
are set forth, for example, in U.S. Pat. No. 2,953,838 to Crawford
et al. and U.S. Pat. No. 2,794,239 to Crawford et al., which are
incorporated by reference herein.
[0080] For filter elements including an expandable or other
degradation-enhancing objects embodied as one or more capsules or
pellets, the filter-forming step may include placement of the one
or more capsules and/or pellets into assembled filter tow in a
manner similar to methods now known and used for capsule or pellet
insertion. Methods and machines for completing this assembly step
include those disclosed in U.S. Pat. No. 7,115,085 to Deal et al.
and U.S. Pat. No. 7,479,098 to Thomas et al., each of which is
incorporated by reference. Superabsorbent, otherwise expandable,
and/or other degradation-enhancing objects may be distributed into
filter tow before or during the time it is spread and gathered for
bulking, fed into the filter tow as it is gathered for bulking,
placed into a cavity in the filter (e.g., in the manner used for
providing charcoal granules in charcoal segmented filters), or by
any other method appropriate for distributing one or more
particles, pellets, rods, threads, or other shaped or amorphous
degradation-enhancing objects including superabsorbent and other
expandable objects. Methods for including a superabsorbent material
into a smoking article filter may include but are not limited to:
capsule insertion technology, pellet insertion technology, thread
insertion technology using a hydrogel or other superabsorbent
polymer or other material formed into a thread/strand or by
adhering grains of hydrogel to a carrier thread, sprinkling of
grains into tow band, and/or inclusion into filter tow with a
plasticizer
[0081] Filter element components or segments for filter elements
for multi-segment filtered cigarettes typically are provided from
filter rods that are produced using traditional types of
rod-forming units, such as those available as KDF-2 and KDF-3E from
Hauni-Werke Korber & Co. KG. Typically, filter material, such
as filter tow, is provided using a tow processing unit. An
exemplary tow processing unit has been commercially available as
E-60 supplied by Arjay Equipment Corp., Winston-Salem, NC. Other
exemplary tow processing units have been commercially available as
AF-2, AF-3, and AF-4 from Hauni-Werke Korber & Co. KG. In
addition, representative manners and methods for operating a filter
material supply units and filter-making units are set forth in U.S.
Pat. No. 4,281,671 to Byrne; U.S. Pat. No. 4,862,905 to Green, Jr.
et al.; U.S. Pat. No. 5,060,664 to Siems et al.; U.S. Pat. No.
5,387,285 to Rivers; and U.S. Pat. No. 7,074,170 to Lanier, Jr. et
al. Other types of technologies for supplying filter materials to a
filter rod-forming unit are set forth in U.S. Pat. No. 4,807,809 to
Pryor et al. and U.S. Pat. No. 5,025,814 to Raker; which are
incorporated herein by reference.
[0082] Cigarette filter rods can be used to provide multi-segment
filter rods. The production of multi-segment filter rods can be
carried out using the types of rod-forming units that traditionally
have been employed to provide multi-segment cigarette filter
components. Multi-segment cigarette filter rods can be manufactured
using a cigarette filter rod making device available under the
brand name Mulfi from Hauni-Werke Korber & Co. KG of Hamburg,
Germany. Representative types of filter designs and components,
including representative types of segmented cigarette filters, are
set forth in U.S. Pat. No. 4,920,990 to Lawrence et al.; U.S. Pat.
No. 5,012,829 to Thesing et al.; U.S. Pat. No. 5,025,814 to Raker;
U.S. Pat. No. 5,074,320 to Jones, Jr. et al.; U.S. Pat. No.
5,105,838 to White et al.; U.S. Pat. No. 5,271,419 to Arzonico et
al.; U.S. Pat. No. 5,360,023 to Blakley et al.; U.S. Pat. No.
5,396,909 to Gentry et al.; and U.S. Pat. No. 5,718,250 to Banerjee
et al; U.S. Pat. Appl. Pub. Nos. 2002/0166563 to Jupe et al.,
2004/0261807 to Dube et al.; 2005/0066981 to Crooks et al.;
2006/0090769 to Woodson et al.; 2006/0124142 to Zhang; 2006/0144412
to Mishra et al., 2006/0157070 to Belcastro et al.; and
2007/0056600 to Coleman, III et al.; PCT Publication No. WO
03/009711 to Kim; PCT Publication No. WO 03/047836 to Xue et al.;
all of which are incorporated herein by reference.
[0083] Multi-segment filter elements typically are provided from
so-called "six-up" filter rods, "four-up" filter rods and "two-up"
filter rods that are of the general format and configuration
conventionally used for the manufacture of filtered cigarettes can
be handled using conventional-type or suitably modified cigarette
rod handling devices, such as tipping devices available as Lab MAX,
MAX, MAX S or MAX 80 from Hauni-Werke Korber & Co. KG. See, for
example, the types of devices set forth in U.S. Pat. No. 3,308,600
to Erdmann et al.; U.S. Pat. No. 4,281,670 to Heitmann et al.; U.S.
Pat. No. 4,280,187 to Reuland et al.; U.S. Pat. No. 4,850,301 to
Greene, Jr. et al.; and U.S. Pat. No. 6,229,115 to Vos et al.; and
U.S. Pat. Application Publication Nos. 2005/0103355 to Holmes,
2005/1094014 to Read, Jr., and 2006/0169295 to Draghetti, each of
which is incorporated herein by reference.
[0084] Manners and methods for incorporating degradable particles
and/or superabsorbent objects into desired regions of the filter
element can vary. The particles can be incorporated into a
polymeric material prior to fiber formation, incorporated into the
fibrous filter materials during the fiber formation process, or
incorporated into the fibrous tow during the rod-forming
process.
[0085] For example, the particles and/or superabsorbent objects
could be introduced into the cellulose acetate or polyolefin "dope"
prior to spinning the cellulose acetate or polyolefin fibers. For
degradable particles, starch particles may be admixed into the
fiber precursor solution. In such an embodiment, the particles are
preferably insoluble in the dope solvent (e.g., acetone) and
instead form a slurry or dispersion in the liquid composition.
Alternatively, the particles can be soluble in the dope solvent.
Still further, the degradable particles could be dry-blended with
the polymer (e.g., polypropylene or cellulose acetate) prior to
fiber formation, such as by using a twin-screw extruder
conventionally used to mix additives with polymeric materials. U.S.
Pat. No. 6,136,246 to Rauwendaal et al., which is incorporated by
reference herein, discloses an exemplary screw extruder that could
be used to mix degradable particles and/or superabsorbent objects
with a polymer material prior to fiber formation. One advantage of
incorporating the particles into the fibers prior to, or during,
fiber formation is that each individual fiber that forms the
fibrous tow filter material will have a plurality of degradable
particles dispersed and imbedded therein, which may enhance
degradation of the filter element produced using the fibers. The
amount of degradable particles added to the fiber precursor
solution or admixed with a polymeric material using a dry-blending
technique is typically in the range of about 5 to about 40% by
weight, more often about 10 to about 30% by weight, based on the
total weight of the precursor solution or total weight of the
blended components.
[0086] In another method, particulate materials (including
superabsorbent objects) can be incorporated into "dalmation" types
of filter regions using the general types of techniques used to add
particulate material in traditional dalmation filter manufacture.
Techniques for production of dalmation filters are known, and
representative dalmation filters have been provided commercially by
Filtrona Greensboro Inc. Alternatively, any other known types of
techniques and equipment for producing filter segments
incorporating granular materials can be suitably altered so as to
introduce degradable particles and/or superabsorbent objects into
regions of filter segments. Unlike superabsorbent objects,
degradable particles can be applied to the fibrous tow as a slurry
in a suitable solvent (e.g., water). However, either may be added
as free-flowing particulates. The particles can also be applied
within a binder or adhesive matrix, or attached to a carrier
material, such as a carrier fiber or capsule, and inserted into the
fibrous tow with the carrier material. In certain alternative
embodiments, the degradable particles and/or superabsorbent objects
(when the latter are initially presented in smaller,
particulate-range sizes) can be introduced to the inner surface of
the plug wrap or within the side seam adhesive formulation.
Exemplary processes for introducing additives into fibrous filter
tow during filter rod formation are set forth in U.S. Pat.
Application Publication Nos. 2008/0029118 to Nelson et al. and
2008/0302373 to Stokes et al., as well as in U.S. application Ser.
No. 12/124,891 filed May 21, 2008; Ser. No. 12/259,838 filed Oct.
28, 2008; and Ser. No. 12/407,260 filed Mar. 19, 2009, all of which
are incorporated by reference herein in their entirety.
[0087] Filter elements of the present invention can be incorporated
within the types of cigarettes set forth in U.S. Pat. No. 4,756,318
to Clearman et al.; U.S. Pat. No. 4,714,082 to Banerjee et al.;
U.S. Pat. No. 4,771,795 to White et al.; U.S. Pat. No. 4,793,365 to
Sensabaugh et al.; U.S. Pat. No. 4,989,619 to Clearman et al.; U.S.
Pat. No. 4,917,128 to Clearman et al.; U.S. Pat. No. 4,961,438 to
Korte; U.S. Pat. No. 4,966,171 to Serrano et al.; U.S. Pat. No.
4,969,476 to Bale et al.; U.S. Pat. No. 4,991,606 to Serrano et
al.; U.S. Pat. No. 5,020,548 to Farrier et al.; U.S. Pat. No.
5,027,836 to Shannon et al.; U.S. Pat. No. 5,033,483 to Clearman et
al.; U.S. Pat. No. 5,040,551 to Schlatter et al.; U.S. Pat. No.
5,050,621 to Creighton et al.; U.S. Pat. No. 5,052,413 to Baker et
al.; U.S. Pat. No. 5,065,776 to Lawson; U.S. Pat. No. 5,076,296 to
Nystrom et al.; U.S. Pat. No. 5,076,297 to Farrier et al.; U.S.
Pat. No. 5,099,861 to Clearman et al.; U.S. Pat. No. 5,105,835 to
Drewett et al.; U.S. Pat. No. 5,105,837 to Barnes et al.; U.S. Pat.
No. 5,115,820 to Hauser et al.; U.S. Pat. No. 5,148,821 to Best et
al.; U.S. Pat. No. 5,159,940 to Hayward et al.; U.S. Pat. No.
5,178,167 to Riggs et al.; U.S. Pat. No. 5,183,062 to Clearman et
al.; U.S. Pat. No. 5,211,684 to Shannon et al.; U.S. Pat. No.
5,240,014 to Deevi et al.; U.S. Pat. No. 5,240,016 to Nichols et
al.; U.S. Pat. No. 5,345,955 to Clearman et al.; U.S. Pat. No.
5,396,911 to Casey, III et al.; U.S. Pat. No. 5,551,451 to Riggs et
al.; U.S. Pat. No. 5,595,577 to Bensalem et al.; U.S. Pat. No.
5,727,571 to Meiring et al.; U.S. Pat. No. 5,819,751 to Barnes et
al.; U.S. Pat. No. 6,089,857 to Matsuura et al.; U.S. Pat. No.
6,095,152 to Beven et al; and U.S. Pat. No. 6,578,584 to Beven;
which are incorporated herein by reference. Still further, filter
elements of the present invention can be incorporated within the
types of cigarettes that have been commercially marketed under the
brand names "Premier" and "Eclipse" by R. J. Reynolds Tobacco
Company. See, for example, those types of cigarettes described in
Chemical and Biological Studies on New Cigarette Prototypes that
Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company
Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000);
which are incorporated herein by reference.
[0088] Cigarette rods typically are manufactured using a cigarette
making machine, such as a conventional automated cigarette rod
making machine. Exemplary cigarette rod making machines are of the
type commercially available from Molins PLC or Hauni-Werke Korber
& Co. KG. For example, cigarette rod making machines of the
type known as MkX (commercially available from Molins PLC) or
PROTOS (commercially available from Hauni-Werke Korber & Co.
KG) can be employed. A description of a PROTOS cigarette making
machine is provided in U.S. Pat. No. 4,474,190 to Brand, at col. 5,
line 48 through col. 8, line 3, which is incorporated herein by
reference. Types of equipment suitable for the manufacture of
cigarettes also are set forth in U.S. Pat. No. 4,781,203 to La Hue;
U.S. Pat. No. 4,844,100 to Holznagel; U.S. Pat. No. 5,131,416 to
Gentry; U.S. Pat. No. 5,156,169 to Holmes et al.; U.S. Pat. No.
5,191,906 to Myracle, Jr. et al.; U.S. Pat. No. 6,647,870 to Blau
et al.; U.S. Pat. No. 6,848,449 to Kitao et al.; and U.S. Pat. No.
6,904,917 to Kitao et al.; and U.S. Pat. Application Publication
Nos. 2003/0145866 to Hartman; 2004/0129281 to Hancock et al.;
2005/0039764 to Barnes et al.; and 2005/0076929 to Fitzgerald et
al.; each of which is incorporated herein by reference.
[0089] The components and operation of conventional automated
cigarette making machines will be readily apparent to those skilled
in the art of cigarette making machinery design and operation. For
example, descriptions of the components and operation of several
types of chimneys, tobacco filler supply equipment, suction
conveyor systems and garniture systems are set forth in U.S. Pat.
No. 3,288,147 to Molins et al.; U.S. Pat. No. 3,915,176 to Heitmann
et al.; U.S. Pat. No. 4,291,713 to Frank; U.S. Pat. No. 4,574,816
to Rudszinat; U.S. Pat. No. 4,736,754 to Heitmann et al. U.S. Pat.
No. 4,878,506 to Pinck et al.; U.S. Pat. No. 5,060,665 to Heitmann;
U.S. Pat. No. 5,012,823 to Keritsis et al. and U.S. Pat. No.
6,360,751 to Fagg et al.; and U.S. Pat. Publication No.
2003/0136419 to Muller; each of which is incorporated herein by
reference. The automated cigarette making machines of the type set
forth herein provide a formed continuous cigarette rod or smokable
rod that can be subdivided into formed smokable rods of desired
lengths.
[0090] Preferred cigarettes of the present invention exhibit
desirable resistance to draw. For example, an exemplary cigarette
exhibits a pressure drop of between about 50 and about 200 mm water
pressure drop at 17.5 cc/sec. air flow. Preferred cigarettes
exhibit pressure drop values of between about 60 mm and about 180,
more preferably between about 70 mm to about 150 mm, water pressure
drop at 17.5 cc/sec. air flow. Typically, pressure drop values of
cigarettes are measured using a Filtrona Cigarette Test Station
(CTS Series) available from Filtrona Instruments and Automation
Ltd.
[0091] Those of skill in the art will appreciate that embodiments
not expressly illustrated herein may be practiced within the scope
of the present invention, including that features described herein
for different embodiments may be combined with each other and/or
with currently-known or future-developed technologies while
remaining within the scope of the claims presented here. It is
therefore intended that the foregoing detailed description be
regarded as illustrative rather than limiting. And, it should be
understood that the following claims, including all equivalents,
are intended to define the spirit and scope of this invention.
* * * * *