U.S. patent application number 13/045037 was filed with the patent office on 2012-09-13 for smoking articles and wrapping materials therefor.
Invention is credited to Paul S. Chapman, Evon L. Crooks, Alan B. Norman, Robert L. Oglesby.
Application Number | 20120227754 13/045037 |
Document ID | / |
Family ID | 46794392 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120227754 |
Kind Code |
A1 |
Norman; Alan B. ; et
al. |
September 13, 2012 |
SMOKING ARTICLES AND WRAPPING MATERIALS THEREFOR
Abstract
A smoking article includes a smokable rod manufactured using a
paper wrapping material having an additive material applied thereto
as a pattern. The additive material is applied as coating
formulation (e.g., an aqueous coating formulation) incorporating a
film-forming agent such as alginate, starch, or another polymer.
The wrapping material includes at least one coated region with a
porosity of less than about 20 CORESTA and a diffusion capacity no
greater than about 0.2 cm/sec, where the coated region is on a base
sheet with a porosity of greater than about 120 CORESTA and a
diffusion capacity of at least 1.7 cm/sec.
Inventors: |
Norman; Alan B.; (Clemmons,
NC) ; Chapman; Paul S.; (Winston-Salem, NC) ;
Oglesby; Robert L.; (Kernersville, NC) ; Crooks; Evon
L.; (Mocksville, NC) |
Family ID: |
46794392 |
Appl. No.: |
13/045037 |
Filed: |
March 10, 2011 |
Current U.S.
Class: |
131/365 |
Current CPC
Class: |
A24D 1/025 20130101 |
Class at
Publication: |
131/365 |
International
Class: |
A24D 1/02 20060101
A24D001/02 |
Claims
1. A wrapping material for a smoking article, the wrapping material
comprising a base sheet and an additive material disposed on at
least one major surface thereof in a pattern forming at least one
coated region, where the additive material is configured to reduce
a porosity of the base sheet, so as to reduce its ignition
propensity in the coated region; wherein the at least one coated
region comprises a porosity of less than about 20 CORESTA and a
diffusion capacity no greater than about 0.2 cm/sec; wherein the
base sheet comprises a porosity of greater than about 120 CORESTA
and a diffusion capacity of at least 1.7 cm/sec; and wherein the
base sheet comprises an ash conditioner.
2. The wrapping material of claim 1 wherein the at least one coated
region comprises a porosity of less than about 10 CORESTA.
3. The wrapping material of claim 1 wherein the at least one coated
region comprises a porosity of less than about 5 CORESTA.
4. The wrapping material of claim 1 wherein the at least one coated
region comprises a diffusion capacity less than about 0.1 cm/sec
.
5. The wrapping material of claim 1 wherein the at least one coated
region comprises a diffusion capacity less than about 0.09
cm/sec.
6. The wrapping material of claim 1 wherein the base sheet
comprises a porosity of greater than about 130 CORESTA.
7. The wrapping material of claim 1 wherein the base sheet
comprises a porosity of greater than about 150 CORESTA.
8. The wrapping material of claim 1 wherein the base sheet
comprises a porosity of at least about 200 CORESTA.
9. The wrapping material of claim 1 wherein the ash conditioner
consists essentially of a non-sodium metal citrate.
10. The wrapping material of claim 1 wherein the ash conditioner
consists essentially of potassium citrate.
11. The wrapping material of claim 10, wherein the potassium
citrate is present on a dry weight basis at about 0.4% to about
1%.
12. The wrapping material of claim 1 wherein the base sheet
comprises a diffusion capacity of at least about 1.9 cm/sec.
13. The wrapping material of claim 1 wherein the base sheet
comprises a diffusion capacity of at least about 2.2 cm/sec.
14. A smoking article comprising the wrapping material of any of
claims 1, 2, 5, 7, 8, or 10.
15. A wrapping material for a smoking article, the wrapping
material comprising a base sheet and an additive material disposed
on at least one major surface thereof in a pattern forming at least
one coated region, where the additive material is configured to
reduce a porosity of the base sheet, so as to reduce its ignition
propensity in the coated region; wherein the at least one coated
region comprises a porosity of less than about 10 CORESTA and a
diffusion capacity less than about 0.2 cm/sec; wherein the base
sheet comprises a porosity of greater than about 150 CORESTA and a
diffusion capacity of at least 2 cm/sec; and wherein the base sheet
comprises a non-sodium metal citrate ash conditioner.
16. A smoking article comprising the wrapping material of claim 15.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to products made or derived
from tobacco, or that otherwise incorporate tobacco, and are
intended for human consumption. More particularly, aspects of the
present invention relate to wrapping materials and to smoking
articles associated with those smoking articles.
BACKGROUND OF THE INVENTION
[0002] 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, surrounded
by a paper wrapper, to form a "cigarette rod," "smokable rod" or a
"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
cigarettes incorporate filter elements comprising, for example,
activated charcoal particles. Typically, the filter element is
attached to one end of the tobacco rod using a circumscribing
wrapping material known as "tipping paper." In some smoking
articles, the tipping material and plug wrap are perforated in
order to provide dilution of drawn mainstream smoke with ambient
air. Descriptions of cigarettes and the various components thereof
are set forth Tobacco Production, Chemistry and Technology, Davis
et al. (Eds.) 1999. Various properties of paper materials used for
cigarette manufacture, and of the cigarettes manufactured using
those papers, are set forth in Durocher, TJI, 188-194 (3/1985). For
example, cigarette wrapping paper materials are known in the art as
having a variety of CORESTA values up to about 200 CORESTA. The
base porosity of cigarette wrapping paper materials in typical or
common cigarettes is often greater than 20 CORESTA and less than
100 CORESTA, with many products having materials in about the 30 to
60 CORESTA range. CORESTA are a measure of the air flow through
paper (cm.sup.3 of air at 1 kPa pressure flowing through one
cm.sup.2 of paper area per minute).
[0003] A cigarette is used by a smoker by lighting one end of that
cigarette, and burning the tobacco rod. The smoker then receives
mainstream smoke into his or her mouth by drawing on the opposite
end of the cigarette. During the time that the cigarette is not
being drawn upon by the smoker, the cigarette remains burning.
[0004] Numerous attempts have been made to control the manner that
a cigarette burns when the cigarette is not being drawn upon. For
example, cigarette papers have been treated with various materials
to cause cigarettes incorporating those papers to self extinguish
during periods when those cigarettes are lit but are not being
actively puffed. Certain treatment methods have involved applying
materials to the paper in circumferential bands or longitudinal
stripes, creating areas that affect the burn rate of cigarettes
incorporating that type of cigarette paper. See, for example, U.S.
Pat. No. 4,924,888 to Perfetti U.S. Pat. No. 3,030,963 to Cohn;
U.S. Pat. No. 4,146,040 to Cohn; U.S. Pat. No. 4,489,738 to Simon;
U.S. Pat. No. 4,480,650 to Weinert; U.S. Pat. No. 4,615,345 to
Durocher; U.S. Pat. No. 6,606,999 to Crooks et al; U.S. Pat. No.
6,827,087 to Wanna et al; and U.S. Pat. No. 6,848,449 to Kitao et
al.; U.S. Pat. No. 6,904,917 to Kitao et al.; and U.S. Patent
Application Pub. Nos. 2004/0231685 to Patel et al.; 2005/0016556 to
Ashcraft et al.; and 2005/0076929 to Fitzgerald et al.; each of
which is incorporated herein by reference. In addition, numerous
references disclose applying films to the paper wrapping materials
of tobacco rods. See, for example, U.S. Pat. No. 1,909,924 to
Schweitzer; U.S. Pat. No. 4,607,647 to Dashley; and U.S. Pat. No.
5,060,675 to Milford et al., each of which is incorporated herein
by reference. Some cigarettes have included tobacco rods and
multiple layers of circumscribing wrapping materials such as, for
example. U.S. Pat. No. 4,998,543 to Goodman; U.S. Pat. No.
5,220,930 to Gentry; and U.S. Pat. No. 5,271,419 to Arzonico et
al.
[0005] "Banded" paper wrapping materials that are used for
cigarette manufacture include segments defined by the composition,
location, and properties of the various materials within those
wrapping materials. Numerous references contain disclosures
suggesting various banded wrapping material configurations. See,
for example, U.S. Pat. No. 1,996,002 to Seaman; U.S. Pat. No.
2,013,508 to Seaman; U.S. Pat. No. 4,452,259 to Norman et al.; U.S.
Pat. No. 5,417,228 to Baldwin et al.; U.S. Pat. No. 5,878,753 to
Peterson et al.; U.S. Pat. No. 5,878,754 to Peterson et al.; U.S.
Pat. No. 6,198,537 to Bokelman et al.; U.S. Pat. No. 6,779,530 to
Kraker; U.S. Pat. No. 6,837,248 to Zawadzki et al; and U.S. Pat.
No. 6,725,867 to Peterson et al.; and U.S. Patent Application Pub.
Nos. 2005/0016556 to Ashcraft et al. and 2005/0229941 to Minami et
al.; each of which is incorporated herein by reference.
[0006] Methods for manufacturing banded-type wrapping materials
also have been disclosed. See, for example, U.S. Pat. No. 4,739,775
to Hampl, Jr. et al.; and U.S. Pat. No. 5,474,095 to Allen et al.;
and PCT Application Pub. Nos. WO 02/44700 to Watkins and WO
02/055294 to Hammersmith et al. Some of those references describe
banded papers having segments of paper, fibrous cellulosic
material, or particulate material adhered to a paper web. See, U.S.
Pat. No. 5,263,999 to Baldwin et al.; U.S. Pat. No. 5,417,228 to
Baldwin et al.; U.S. Pat. No. 5,450,863 to Collins et al.; and U.S.
Pat. No. 6,502,613 to Suzuki; and U.S. Patent Application Pub. No.
2005/0045297 to Garg et al. A representative method for
manufacturing cigarettes having treated wrapping materials is set
forth in U.S. Pat. No. 5,191,906 to Myracle, Jr. et al. Additive
materials can be applied to cigarette paper wrapping materials
while those wrapping materials are being used for cigarette
manufacture (i.e., in a so-called "on-line" fashion). See, for
example, U.S. Pat. No. 1,999,223 to Weinberger; U.S. Pat. No.
1,999,224 to Miles; and U.S. Pat. No. 6,848,449 to Kitao et al.;
U.S. Pat. No. 6,904,917 to Kitao et al.; and U.S. Patent
Application Pub. Nos. 2004/0129281 to Hancock et al; 2004/0261805
to Wanna et al; 2005/0039764 to Barnes et al.; and 2005/0076929 to
Fitzgerald et al.; each of which is incorporated herein by
reference.
[0007] The wrapping materials configured with these structures may
generally and variously be known as Low-Ignition-Propensity paper
and/or FSC paper (which has been used in the art as an acronym for
both "fire standards compliant" and "fire-safe cigarette"
paper).
[0008] It may be desirable to supply such wrapping materials with a
smoking article that provides reduced carbon monoxide in mainstream
smoke. It has been observed that some smoking articles manufactured
in compliance with government regulation FSC paper may deliver
increased levels of carbon monoxide (see, e.g., "'Fire Safer'
Cigarettes: The Effect Of The New York State Cigarette Fire Safety
Standard On Ignition Propensity, Smoke Toxicity, And The Consumer
Market" Alpert, et al., Harvard School of Public Health, 2005).
Thus, it may be desirable to provide smoking articles that include
desirable reduced-ignition propensity features, but that do so
without any increase in carbon monoxide delivery.
SUMMARY OF THE INVENTION
[0009] The present invention provides materials and methods related
to manufacturing smoking articles, such as cigarettes. In a
preferred aspect of the present invention, a suitable additive
material is applied to the wrapping material of a cigarette rod,
and that additive material includes at least one type of
film-forming component. Certain additive materials incorporate a
mixture of polymeric film-forming components. The additive material
is applied to at least one major surface of the wrapping material,
and most preferably, to one major surface of the wrapping
material.
[0010] Certain embodiments of the present invention may relate to
wrapping materials having additive material formulations applied
thereto (most preferably in a controlled manner), and to cigarettes
manufactured from those wrapping materials. For example, additive
material is applied to a wrapping material as a formulation of the
present invention; and that formulation incorporates at least one
type of polymeric agent, and can incorporate a polymeric agent
mixture. The base wrapping material may include a
higher-than-traditional porosity (that is, greater than about 100
CORESTA to greater than 110 CORESTA to greater than 120 CORESTA).
In certain embodiments, the base wrapping material may include
higher diffusion capacities as well, on the order of about 1.6
cm/sec or greater.
[0011] In another aspect of certain embodiments of the invention, a
representative additive material formulation, and in particular, a
representative polymeric agent mixture, most preferably
incorporates a polymeric material that can be characterized as
providing film-forming properties to the formulation; that is, an
agent that provides desirable functional effects or properties to
the formulation. That is, film-forming agents act to provide a
formulation that can allow the formulation to be applied to the
wrapping material in a desired manner (e.g., as a pre-determined
pattern), and can provide a treated wrapping material that exhibits
desired functional behaviors. Representative film-forming agents
include polymeric materials of varying molecular weights. The
thickening agent and the film-forming agent can be provided by one
particular type of polymeric material, or one type of polymeric
material that is provided in at least two forms, or at least two
ranges of molecular weights. That is, certain polymeric materials
can have the ability to act as both film-forming and thickening
agents. Alternatively, the thickening agent can be provided by one
type of polymeric material, and the film-forming agent can be
provided by a different type of polymeric material.
[0012] Representative formulations of additive materials may
include water-based formulations and/or formulations containing
water-miscible components (e.g., one or more alcohols), or that are
non-aqueous based (e.g., organic solvent) in nature.
[0013] Optional ingredients, such as flavoring agents,
preservatives, pigments and/or colorants, also can be incorporated
into the aforementioned formulations. Ingredients such as water
soluble and/or water insoluble filler materials (e.g., sodium
chloride, calcium chloride, potassium citrate and/or calcium
carbonate) also can be incorporated into those formulations.
[0014] Other embodiments of the present invention may include a
method for transferring additive material to, and retaining
additive material on, desired locations of a wrapping material
(e.g., paper wrapping web). For example, wrapping material having a
formulation incorporating a polymeric agent mixture (e.g., a
formulation having an adhesive-type of character or nature)
disposed thereon or otherwise applied thereto (e.g., by printing)
can have liquid solvent or carrier removed (e.g., the treated
wrapping material can be dried to remove significant amounts of
water, when the formulation is a water-based formulation) and wound
onto a roll that is adapted for later use for smoking article
manufacture.
[0015] Other aspects of the present invention may include a method
for transferring the polymeric agent mixture, and retaining that
mixture on, desired locations of, a wrapping material suitable for
use for smoking article manufacture (e.g., paper wrapping web) when
manufacturing smoking articles from those materials using a
cigarette making machine. That is, a formulation of additive
material is applied to a continuously advancing strip of a paper
web within a region of an automated cigarette-making machine system
(e.g., a machine designed to produce a continuous cigarette rod) in
a desired amount, in a desired configuration and in a desired
location.
[0016] For a wrapping material of the present invention, the region
thereof coated with coating formulation of the present invention
most preferably will exhibit a diffusion capacity in that coated
region that is lower than in an uncoated region.
[0017] In another embodiment of the invention, a smoking article
incorporating a tobacco rod manufactured from wrapping material
treated with the additive material formulation of the present
invention may include at least one band of additive material
located in a region of its tobacco rod such that the band is
capable of providing that smoking article with the ability to meet
certain smoking article extinction criteria. Certain smoking
articles of the present invention including tobacco rods
manufactured using certain appropriately treated wrapping
materials, when tested using the methodology set forth in the
Cigarette Extinction Test Method by the National Institute of
Standards and Technology (NIST), Pub. 851 (1993) using 10 layers of
Whatman No. 2 filter paper, meet criteria requiring extinction of
greater than about 50 percent, preferably greater than about 75
percent, more preferably greater than about 90 percent, and most
preferably about 100 percent, of cigarettes tested. Certain
cigarettes of the present invention including tobacco rods
manufactured using certain appropriately treated wrapping
materials, when tested using the methodology set forth in the
methodology set forth in ASTM Designation: E 2187-02b using 10
layers of Whatman No. 2 filter paper, meet criteria requiring
extinction of greater than about 50 percent, preferably greater
than about 75 percent, more preferably greater than about 90
percent, and most preferably about 100 percent, of cigarettes
tested. This measurement may be characterized as "ASTM SE %" with
reference to self-extinguishing behavior under the ASTM testing
conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an exploded perspective of smoking article,
showing the smokable material, the wrapping material components,
and the filter element.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring to FIG. 1, there are shown the components of a
smoking article 174 in the form of a cigarette. The cigarette 174
includes a generally cylindrical rod 186 of a charge or roll of
smokable filler material 188 contained in a circumscribing wrapping
material 190 of the present invention. The rod 186 is
conventionally referred to as a "tobacco rod". The ends of the
tobacco rod are open to expose the smokable filler material. At one
end of the tobacco rod 186 is the lighting end 195, and at the
other end is shown a filter element 200. The cigarette 174 is shown
as having one printed band 202 printed on wrapping material 190,
and that band entirely circumscribes the cigarette rod in a
direction transverse to the longitudinal axis of the cigarette.
That is, the band 202 provides a cross-directional region relative
to the longitudinal axis of the cigarette 174. The band 202 most
preferably is applied to the inner surface of the wrapping material
190 (i.e., facing the smokable filler material), but can be, in a
much less preferred embodiment, applied to the outer surface of the
wrapping material 190. Although the cigarette 174 shown in FIG. 1
has wrapping material having one band, the cigarette also can
include wrapping material having two, three, or more spaced bands.
The band 202 comprises additive materials of a water-based coating
formulation that incorporates a polymeric agent mixture of the
present invention.
[0020] The cigarette 174 normally includes a filter element 200 or
other suitable mouthpiece positioned adjacent one end of the
tobacco rod 186 such that the filter element and tobacco rod are
axially aligned in an end-to-end relationship, preferably abutting
one another. Filter element 200 has a generally cylindrical shape,
and the diameter thereof is essentially equal to the diameter of
the tobacco rod. The ends of the filter element are open to permit
the passage of air and smoke therethrough. The filter element 200
includes filter material 205 (e.g., plasticized cellulose acetate
tow) that is overwrapped along the longitudinally extending surface
thereof with circumscribing plug wrap material 206. The filter
element 200 can have two or more filter segments, and/or flavor
additives incorporated therein.
[0021] The filter element 200 is attached to the tobacco rod 186 by
tipping material 208 which circumscribes both the entire length of
the filter element and an adjacent region of the tobacco rod. The
inner surface of the tipping material 208 preferably is secured to
the outer surface of the plug wrap 206 and the outer surface of the
wrapping material 190 of the tobacco rod using a suitable adhesive.
A ventilated or air-diluted smoking article is provided with an
air-dilution means, such as a series of perforations 210, each of
which extend through the tipping material and plug wrap.
[0022] Various representative types of cigarette components are set
forth in U.S. Pat. No. 5,220,930 to Gentry and U.S. Patent
Application Pub. Nos. 2004/0255965 to Perfetti et al.; 2004/0261807
to Dube et al.; 2005/0066982 to Clark et al. and 2005/0066986 to
Nestor et al., which are incorporated herein by reference. See,
also, Johnson, Development of Cigarette Components to Meet Industry
Needs, 52.sup.nd T.S.R.C. (September 1998). In addition,
representative cigarette components and methods for manufacturing
cigarettes from those components are set forth in U.S. Pat. No.
7,565,818, to Thomas et al., which is incorporated herein by
reference.
[0023] Various types of equipment and methods for manufacturing
cigarettes, and for applying additive material formulation to
smoking article wrapping material, are known. For example,
representative types of equipment and the operation thereof are set
forth in U.S. Pat. No. 6,848,449 to Kitao et al.; U.S. Pat. No.
6,904,917 to Kitao et al.; U.S. Patent Application Pub. Nos.
2004/0129281 to Hancock et al.; 2004/0231685 to Patel et al; and
2005/0039764 to Barnes et al.; and 2005/0076929 to Fitzgerald et
al.; which are incorporated herein by reference. Other
representative techniques for applying additive material
formulation to wrapping material are set forth in U.S. Pat. No.
6,779,530 to Kraker; U.S. Patent Application Pub. Nos. 2005/0016556
to Ashcraft et al.; 2005/0103355 to Holmes and 2005/0194014 to
Read, Jr.; and PCT WO04/095957 to Bray et al., which are
incorporated herein by reference. As such, there are various known
manners and methods for applying additive material formulations in
a desired manner (e.g., as a coating or film) to desired locations
and/or in desired patterns on wrapping materials, such as paper
wrapping materials suitable for use for the manufacture of tobacco
rods for cigarettes.
[0024] Coating formulations incorporating the additive material for
bands or other patterns configured to reduce ignition propensity by
reducing air flow to the underlying tobacco rod typically are
applied to wrapping material that is supplied from a roll. In one
regard, the formulation can be applied to wrapping material
supplied from a bobbin. The amount of wrapping material on a bobbin
can vary, but the length of continuous strip of wrapping material
on a bobbin typically is more than about 6,000 meters; and
generally, the length of continuous strip of wrapping material on a
bobbin typically is less than about 7,000 meters. The width of the
wrapping material can vary, depending upon factors such as the
circumference of the smokable rod that is manufactured and the
width of the overlap region zone that provides for the sideseam.
Typically, the width of a representative continuous strip of
wrapping material useful for cigarette rod manufacture is about 19
mm to about 30 mm.
[0025] Paper wrapping materials of the present invention are useful
as components of smoking articles such as cigarettes. Preferably,
one layer of the wrapping material of the present invention is used
as the wrapping material circumscribing the smokable material, and
thereby forming the tobacco rod of a cigarette. Most preferably,
the wrapping material has the coated regions located on the "wire"
side thereof; and the "wire" side of that wrapping material forms
the inner surface of the circumscribing wrapping material of the
tobacco rod. That is, when the wrapping material is used to
manufacture a smokable rod, the "wire side" major surface of the
wrapping material that circumscribes the smokable material faces
that smokable material. Typically, the "felt" side of the wrapping
material is used as the visible outer surface of the tobacco rod.
The terms "wire side" and "felt side" in referring to the major
surfaces of paper sheet are readily understood as terms of art to
those skilled in the art of paper and cigarette manufacture. The
selection of a particular wrapping material will be readily
apparent to those skilled in the art of cigarette design and
manufacture. Typical paper wrapping materials are manufactured from
fibrous materials (e.g., a cellulosic materials, such as wood pulp
and/or flax), and optional filler materials (e.g., calcium
carbonate), to form so-called "base sheets."
[0026] Wrapping materials of the present invention can be
manufactured without significant modifications to the production
techniques or processing equipment used to manufacture those
wrapping materials. Typical wrapping material base sheets often
have basis weights that vary, and exhibit porosities that also
vary. Typical base sheets have inherent porosities that are at
least about 5 CORESTA, usually are at least about 10 CORESTA, often
are at least about 15 CORESTA, and frequently are at least about 20
CORESTA. Base sheets of the presently presented embodiments may
include inherent porosities greater than about 100 CORESTA, greater
than about 110 CORESTA, greater than about 120 CORESTA, greater
than about 130 CORESTA, greater than about 150 CORESTA, and that
may be at least (and/or that may exceed) about 200 CORESTA. The
term "inherent porosity" refers to the porosity of that wrapping
material itself to the flow of air. One paper wrapping material
base sheet may include wood pulp, calcium carbonate, and an ash
conditioner consisting essentially of potassium citrate and may
exhibit an inherent porosity of greater than about 120 to greater
than about 150 CORESTA. Previous representative wrapping materials
with traditional porosity ranges of about 20 to about 50 CORESTA
include those commercially available paper wrapping materials that
are set forth in U.S. Pat. Application Pub. Nos. 2004/0129281 to
Hancock et al.; 2005/0016556 to Ashcraft et al.; and 2005/0076929
to Fitzgerald et al. Other types of wrapping materials, and
components thereof, are set forth in U.S. Pat. No. 6,868,855 to
Shafer et al. and U.S. Pat. Application Pub. Nos. 2004/0134631 to
Crooks et al. and 2006/0027243 to Matsufuji et al.; and EP 1234514
to Grider et al.; which are each incorporated herein by
reference.
[0027] The base sheets may be treated so as to impart a change to
the overall physical characteristics thereof and/or so as to
introduce a change in the overall chemical compositions thereof.
For example, a base sheet can be electrostatically perforated,
coated with a film, treated with burn chemicals, and/or treated
with flavoring agents or aroma precursors. Various additives can be
added to, or otherwise incorporated into, the wrapping material
simultaneously to, or at different stages during or after, the
paper manufacturing process. See, for example, U.S. Pat.
Application Pub. Nos. 2005/0016556 to Ashcraft et al. and
2005/0076929 to Fitzgerald et al.
[0028] Typical wrapping material base sheets often incorporate
fibrous material, the composition of which can vary. Often, the
fibrous material will be embodied as a cellulosic material, and the
cellulosic material can be a lignocellulosic material. Exemplary
cellulosic materials include flax fibers, hardwood pulp, softwood
pulp, hemp fibers, esparto fibers, kenaf fibers, jute fibers and
sisal fibers. Mixtures of two or more types of cellulosic materials
can be employed. For example, wrapping materials can incorporate
mixtures of flax fibers and wood pulp. The fibers and/or base sheet
constructed therefrom can be bleached or unbleached. Other fibrous
materials that can be incorporated within wrapping materials
include microfibers materials and fibrous synthetic cellulosic
materials. See, for example, U.S. Pat. No. 4,779,631 to Durocher
and U.S. Pat. No. 5,849,153 to Ishino. Representative fibrous
materials, and methods for making wrapping materials therefrom, are
set forth in U.S. Pat. No. 2,754,207 to Schur et al; and U.S. Pat.
No. 5,474,095 to Allen et al.; and PCT App. Publ. No.
WO01/48318.
[0029] Typical wrapping materials also incorporate a filler
material. Often, the filler material has the form of essentially
water insoluble particles. Additionally, the filler material
normally incorporates inorganic components. Filler materials
incorporating calcium salts are particularly preferred. One
exemplary filler material has the form of calcium carbonate, and
the calcium carbonate most preferably is used in particulate form.
See, for example, U.S. Pat. No. 4,805,644 to Hampl; U.S. Pat. No.
5,161,551 to Sanders; and U.S. Pat. No. 5,263,500 to Baldwin et
al.; and PCT App. Publ. No. WO01/48,316. Other filler materials
that may be used may include one or more of agglomerated calcium
carbonate particles, calcium tartrate particles, magnesium oxide
particles, magnesium hydroxide gels; magnesium carbonate-type
materials, clays, diatomaceous earth materials, titanium dioxide
particles, gamma alumina materials, ethylcellulose particles,
nitrocellulose particles, and calcium sulfate particles. See, for
example, U.S. Pat. No. 3,049,449 to Allegrini; U.S. Pat. No.
4,108,151 to Martin; U.S. Pat. No. 4,231,377 to Cline; U.S. Pat.
No. 4,450,847 to Owens; U.S. Pat. No. 4,779,631 to Durocher; U.S.
Pat. No. 4,915,118 to Kaufman; U.S. Pat. No. 5,092,306 to Bokelman;
U.S. Pat. No. 5,109,876 to Hayden; U.S. Pat. No. 5,699,811 to
Paine; U.S. Pat. No. 5,927,288 to Bensalem; U.S. Pat. No. 5,979,461
to Bensalem; and U.S. Pat. No. 6,138,684 to Yamazaki; and European
Pat. App. No. EP357,359. Certain filler-type materials that can be
incorporated into the wrapping materials can have fibrous forms.
For example, components of the filler material can include
materials such as glass fibers, ceramic fibers, carbon fibers and
calcium sulfate fibers. See, for example, U.S. Pat. No. 2,998,012
to Lamm; U.S. Pat. No. 4,433,679 to Cline; and U.S. Pat. No.
5,103,844 to Hayden et al.; PCT App. Publ. No. WO01/41590; and
European Pat. App. No. EP1,084,629. Mixtures of filler materials
can be used. For example, filler material compositions can
incorporate mixtures of calcium carbonate particles and
precipitated magnesium hydroxide gel, mixtures of calcium carbonate
particles and calcium sulfate fibers, or mixtures of calcium
carbonate particles and magnesium carbonate particles.
[0030] There are various ways by which the various additive
components can be added to, or otherwise incorporated into, the
base sheet. Certain additives can be incorporated into the wrapping
material as part of the paper manufacturing process associated with
the production of that wrapping material. Alternatively, additives
can be incorporated into the wrapping material using size press
techniques, spraying techniques, printing techniques, or the like.
Such techniques, known as "off-line" techniques, are used to apply
additives to wrapping materials after those wrapping materials have
been manufactured. Various additives can be added to, or otherwise
incorporated into, the wrapping material simultaneously or at
different stages during or after the paper manufacturing
process.
[0031] The base sheets can be treated further, and those base
sheets can be treated so as to impart a change to the overall
physical characteristics thereof and/or so as to introduce a change
in the overall chemical compositions thereof. For example, the base
sheet can be electrostatically perforated. See, for example, U.S.
Pat. No. 4,924,888 to Perfetti et al. The base sheet also can be
embossed, for example, in order to provide texture to major surface
thereof. Additives can be incorporated into the wrapping material
for a variety of reasons. Representative additives, and methods for
incorporating those additives to wrapping materials, are set forth
in U.S. Pat. No. 5,220,930 to Gentry, which is incorporated herein
by reference. See, also, U.S. Pat. No. 5,168,884 to Baldwin et al.
Certain components, such as alkali metal salts, can act a burn
control additives. Representative salts include alkali metal
succinates, citrates, acetates, malates, carbonates, chlorides,
tartrates, propionates, nitrates and glycolates; including sodium
succinate, potassium succinate, sodium citrate, potassium citrate,
sodium acetate, potassium acetate, sodium malate, potassium malate,
sodium carbonate, potassium carbonate, sodium chloride, potassium
chloride, sodium tartrate, potassium tartrate, sodium propionate,
potassium propionate, sodium nitrate, potassium nitrate, sodium
glycolate and potassium glycolate; and other salts such as
monoammonium phosphate. See, for example, U.S. Pat. No. 2,580,568
to Matthews; U.S. Pat. No. 4,461,311 to Matthews; U.S. Pat. No.
4,622,983 to Matthews; U.S. Pat. No. 4,941,485 to Perfetti et al.;
U.S. Pat. No. 4,998,541 to Perfetti et al.; and PCT App. Publ. No.
WO01/08514. The paper can also be calendared to impart a generally
or substantially uniform smoothness and/or thickness.
[0032] Certain components, such as metal citrates, can act as ash
conditioners or ash sealers. See, for example, European Pat. App.
No. EP1,084,630. A preferred ash conditioner for presently claimed
embodiments may include or consist essentially of potassium
citrate. A preferred ash conditioner may exclude sodium citrate,
and/or it may include or consist essentially of a non-sodium metal
citrate (such as, for example, potassium citrate). Other
representative components include organic and inorganic acids, such
as malic, levulinic, boric and lactic acids. See, for example, U.S.
Pat. No. 4,230,131 to Simon. Other representative components
include catalytic materials. See, for example, U.S. Pat. No.
2,755,207 to Frankenburg. Typically, the amount of chemical
additive does not exceed about 3 percent, often does not exceed
about 2 percent, and usually does not exceed about 1 percent, based
on the dry weight of the wrapping material to which the chemical
additive is applied. For certain wrapping materials, the amount of
certain additive salts, such as burn chemicals such as potassium
citrate and monoammonium phosphate, preferably are in the range of
about 0.5 to about 0.8 percent, based on the dry weight of the
wrapping material to which those additive salts are applied.
Relatively high levels of additive salts can be used on certain
types of wrapping materials printed with printed regions that are
very effective at causing extinction of cigarettes manufactured
from those wrapping materials. Exemplary flax-containing cigarette
paper wrapping materials having relatively high levels of chemical
additives have been available as Grade Names 512, 525, 527, 540,
605 and 664 from Schweitzer-Mauduit International. Exemplary wood
pulp-containing cigarette paper wrapping materials having
relatively high levels of chemical additives have been available as
Grade Names 406 and 419 from Schweitzer-Mauduit International.
[0033] Flavoring agents and/or flavor and aroma precursors (e.g.,
vanillin glucoside and/or ethyl vanillin glucoside) also can be
incorporated into the paper wrapping material. See, for example,
U.S. Pat. No. 4,804,002 to Herron; and U.S. Pat. No. 4,941,486 to
Dube et al. Flavoring agents also can be printed onto cigarette
papers. See, for example, the types of flavoring agents used in
cigarette manufacture that are set forth in Gutcho, Tobacco
Flavoring Substances and Methods, Noyes Data Corp. (1972) and
Leffingwell et al., Tobacco Flavoring for Smoking Products
(1972).
[0034] Films can be applied to the paper. See, for example, U.S.
Pat. No. 4,889,145 to Adams; U.S. Pat. No. 5,060,675 to Milford et
al., and PCT App. Publ. Nos. WO02/43513 and WO02/055294. Catalytic
materials can be incorporated into the paper. See, for example, PCT
App. Publ. No. WO02/435134.
[0035] Typical paper wrapping materials that can be used in
carrying out the present invention may be manufactured under
specifications directed toward the production of a wrapping
material having an overall generally consistent composition and
physical parameters. For those types of wrapping materials, the
composition and parameters thereof preferably are consistent when
considered over regions of each of the major surfaces of those
materials. However, typical wrapping materials tend to have a
"two-sided" nature, and thus, there can be changes in the
composition and certain physical parameters of those materials from
one major surface to the other.
[0036] Though less preferred, the wrapping material can be
manufactured using a paper making process adapted to provide a base
web comprising multiple layers of cellulosic material. See, e.g.,
U.S. Pat. No. 5,143,098 to Rogers et al.
[0037] Certain other paper wrapping materials can have compositions
and/or properties that differ over different regions of each of
their major surfaces. The wrapping material can have regions of
increased or decreased porosity provided by control of the
composition of that material, such as by controlling the amount or
type of the filler. The wrapping material can have regions of
increased or decreased air permeability provided by embossing or
perforating that material. See, for example, U.S. Pat. No.
4,945,932 to Mentzel et al. The wrapping material can have regions
(e.g., pre-determined regions, such as bands) treated with
additives, such as certain of the aforementioned salts. For
wrapping materials having compositions and/or properties that
differ over regions of their major surfaces, alignment and
registration of the printed bands with patterned regions of the
wrapping materials offers manufacturing complications.
[0038] Paper wrapping materials suitable for use in carrying out
the present invention are commercially available. Representative
cigarette paper wrapping materials have been available as Ref. Nos.
419, 454, 456, 460 and 473 Ecusta Corp.; Ref. Nos. Velin 413, Velin
430, VE 825 C20, VE 825 C30, VE 825 C45, VE 826 C24, VE 826 C30 and
856 DL from Miguel; Tercig LK18, Tercig LK24, Tercig LK38, Tercig
LK46 and Tercig LK60 from Tervakoski; and Velin Beige 34, Velin
Beige 46, Velin Beige 60, and Ref. Nos. 454 DL, 454 LV, 553 and 556
from Wattens. Exemplary flax-containing cigarette paper wrapping
materials have been available as Grade Names 105, 114, 116, 119,
170, 178, 514, 523, 536, 520, 550, 557, 584, 595, 603, 609, 615 and
668 from Schweitzer-Mauduit International. Exemplary wood
pulp-containing cigarette paper wrapping materials have been
available as Grade Names 404, 416, 422, 453, 454, 456, 465, 466 and
468 from Schweitzer-Mauduit International.
[0039] The wrapping material base sheet may be pre-treated, prior
to application of an additive material formulation over discrete
regions (e.g., as bands or so as to provide banded regions) to
provide distinct coated areas and/or patterns. That is, the base
sheet most preferably is treated with an appropriate coating
formulation pursuant to the present invention such that virtually
the entire base sheet is treated with a polymeric material (e.g.,
as a coating), and discrete coated areas of additive formulation
may subsequently be applied over the treated base sheet. For
example, virtually the entire major surface of the base sheet can
be treated with a coating formulation incorporating a polymeric
material, such as an alginate. The coating formulation can be
applied to either or both major surfaces of the wrapping material,
or the coating can be applied so as to be dispersed throughout the
base web. Different application techniques may be used for the base
coating formulation. For example, a liquid formulation
incorporating polymeric material can be sprayed on to the base
sheet, printed onto the base sheet, applied using a size press, or
using other suitable application and drying techniques. Preferably,
the amount of polymeric material (e.g., an alginate) applied to
virtually the entire base sheet is less than about 2.5 g/m.sup.2,
often less than about 1 g/m.sup.2, and frequently less than about
0.5 g/m.sup.2, on a dry weight basis. See, for example, U.S. Pat.
Application Pub. Nos. 2005/0016556 to Ashcraft et al. and
2005/0076929 to Fitzgerald et al.
[0040] The amount of polymeric material that is applied to
virtually the entire surface of the base sheet may not be
sufficient on its own to provide self-extinction properties to a
cigarette using the described base sheet. That is, the diffusion
capacity of such a treated base sheet region may be less than about
2.5 cm/sec., but typically is greater than about 1 cm/sec., and
often is greater than about 0.5 cm/sec., when measured at
25.degree. C. This range may vary depending upon the initial,
untreated properties of the base sheet. A base sheet treated in
such a manner (e.g., with an alginate) so as to provide a thin but
porous pre-layer thereto can be further treated with additive
material to provide a pattern (e.g., bands) thereon. A
representative base sheet treated with a pre-layer of alginate can,
in some instances, (i) exhibit a controlled porosity and/or
diffusivity, (ii) provide for control of subsequent additive
material application, (iii) provide for improved drying and reduced
blocking of base sheet that is subsequently treated with additive
material, and (iv) provide a means for alternating to some extent
the smoke chemistry of a cigarette manufactured from that treated
base sheet. Regardless of the material or combination of materials
used to create one or more banded regions, the banded regions may
have a CORESTA value of less than 20, less than 15, less than 10,
less than 5, or less than 3.
[0041] Diffusion, with respect to a cigarette wrapping material
having a coated region of additive material, is the amount of gas
transported through the wrapping material when a gas concentration
gradient is present. See, Baker et al., The Diffusion of Carbon
Monoxide out of Cigarettes, Beitr. Tabakforsch., Vol. 9(3), 131-140
(1977); Drake et al., On a Cell to Measure Diffusion Coefficients
of Gases through Cigarette Papers, Int. J. Heat Mass Transfer, Vol.
23, 127-134 (1980); Baker, The Viscous and Inertial Flow of Air
through Perforated Papers, Beitr. Tabakforsch., Vol. 14(5), 253-260
(1989); Miura, Oxygen Diffusion through Cigarette Paper, Beitr.
Tabakforsch., Vol. 19(4), 205-208 (2001); Miura et al., Heat
Emission from a Burning Cigarette, Beitr. Tabakforsch., Vol. 19(5),
24 5-249 (2001); Rostami et al., Modeling the Diffusion of Carbon
Monoxide and Other Gases from the Paper Wrapper of a Cigarette
During Puffing, J. Anal. Pyrolysis, Vol. 66, 263-280 (2003);
Rostami et al., Modeling of a Smoldering Cigarette, J. Anal.
Pyrolysis, Vol. 66, 281-301 (2003). An apparatus suitable for
measuring the diffusion capacity of a wrapping material, including
coated regions thereof, is set forth in U.S. Patent Application
Pub. No. 2005/0087202 to Norman et al., which is incorporated
herein by reference. See, also, Norman et al., Measurement of Gas
Diffusion Capacity of Cigarette Papers, Beitr. Tabakforsch. Int.
Vol. 21 (2205) 425-434 (2005), which is incorporated herein by
reference.
[0042] The coating formulation that is applied to the wrapping
material to form a band or other pattern may include at least one
film-forming agent. The film-forming agent may include a polymeric
material that can be applied to the wrapping material to form a
pattern (e.g., spaced bands), sufficiently adhere to the wrapping
material, and provide a decrease in the air permeability of the
wrapping material in the area where the coating formulation is
applied. The coated/treated region may provide reduced ignition
propensity.
[0043] The coating formulation may also incorporate a thickening
agent. Such a material preferably provides desirable rheological
properties to the formulation. Such a material may be selected, and
employed in a manner, such that the coating formulation has the
form of a paste that can be readily applied in a desired fashion to
the wrapping material. It is preferred that rheology of the coating
formulation is not overly thick or overly thin, but that the paste
is of such consistency that it can be applied to a wrapping
material without damaging the material. Preferred coating
formulations may also function as adhesives, as it is desirable for
those coatings to remain in intimate contact with (e.g., to adhere
to or otherwise remain secured to) desired locations on the
wrapping material where those formulations are applied, and
preferred thickening agents assist in facilitating such behaviors.
Typically, thickening agents are polymeric materials that are
selected on the basis of including relatively high molecular
weights, and hence exhibiting relatively high viscosities when
incorporated within a liquid formulation.
[0044] The thickening agent and the film-forming agent can be
provided by one particular type of polymeric material, or one type
of polymeric material that is provided in at least two forms, or in
more than one range of molecular weights. That is, certain
polymeric materials can have the ability to act as both
film-forming and thickening agents. Alternatively, the thickening
agent can be provided by one type of polymeric material, and the
film-forming agent can be provided by a different type of polymeric
material.
[0045] The film-forming agent(s) may include, for example,
polymeric material or resin. Exemplary film-forming agents include
alginates (e.g., sodium alginate or ammonium alginate, including
those alginates available as Kelcosol from Kelco), pectins (e.g.,
including those available as TIC Pretested HM from TIC Gums),
derivatives of cellulose (e.g., nitrocellulose, hydroxy
ethylcellulose, ethylcellulose, carboxymethylcellulose and
cellulose acetate propionate), ethylene vinyl acetate copolymers,
guar gum (e.g., including Type M, Type MM, Type MM high viscosity
from Frutarom; and Ticagel from TIC Gums), xanthan gum (e.g.,
including Keltrol from Kelco), starch (e.g., corn starch, rice
starch and dextrin), modified starch (e.g., oxidized tapioca starch
and oxidized corn starch), polyvinyl acetate and polyvinyl alcohol.
Exemplary film-forming agents are available as Klucel
hydroxypropylcellulose HPC, Aqualon sodium carboxymethylcellulose
CMC, Natrosol hydroxyethylcellulose HEC and Aqualon ethylcellulose
EC from Hercules Incorporated; and Walocel nitrocellulose and
Walsroder nitrocellulose from Bayer AG. Suitable combinations of
various film-forming agents also can be employed. Exemplary blends
include blends of ethylene vinyl acetate copolymer and polyvinyl
alcohol, blends of ethylcellulose and ethylene vinyl acetate
copolymer, blends of nitrocellulose and ethylene vinyl acetate
copolymer, and blends of ethylcellulose and nitrocellulose. The
aforementioned blends of film-forming agents, including those that
have hydrophobic characters, may be suitable for primary or first
layer coatings for multi-layered coatings.
[0046] One representative polymeric agent is
hydroxypropylcellulose. An exemplary hydroxypropylcellulose is
available as Klucel EF from Hercules, Inc. Another representative
polymeric agent is hydroxypropylmethylcellulose. An exemplary
hydroxypropylmethylcellulose is available as Walocel HM PA2910
(HPMC) from Wolff Cellulosics. Preferably, the amount of a
representative polymeric agent, such as
hydroxypropylmethylcellulose, hydroxypropylcellulose, or a
combination thereof, is at least about 1 percent, generally at
least about 5 percent, and often at least about 10 percent; and
typically does not exceed about 30 percent, generally does not
exceed about 25 percent, and often does not exceed about 20
percent; based on the total weight of the coating formulation prior
to use.
[0047] Exemplary polymeric agents also can include alginates, such
as sodium alginate, potassium alginate, ammonium alginate, and the
like, as well as combinations thereof, and combinations thereof
with one of the other polymeric agents described herein (e.g.,
hydroxypropylcellulose, hydroxypropylmethylcellulose). Exemplary
alginates are available as Kelgin RL, Manucol LD, Manucol LB,
Manugel LBA, and Keltone LVCR NF from FMC Biopolymer. See, for
example, the types of alginates set forth in U.S. Pat. No.
6,779,530 to Kraker and U.S. Pat. App. Pub. No. 2007/0084475 to
Oglesby, each of which is incorporated herein by reference. Other
exemplary alginates are available as Kelgin LDH, Collatex A/RE and
Collatex A/RK from ISP Corporation. Relatively low molecular weight
alginates may act as film-forming agents, while relatively high
molecular weight alginates may act as thickening agents as well as
film-forming agents. If desired, mixtures of alginates, such as
mixtures of relatively high molecular weight alginates and
relatively low molecular weight alginates, may be employed.
Preferably, the amount of an alginate is at least about 1 percent,
may be at least about 5 percent, and often at least about 10
percent; and typically does not exceed about 30 percent, generally
does not exceed about 25 percent, and often does not exceed about
20 percent; based on the total weight of the coating formulation
prior to use. Certain alginates are those that include viscosities
of greater than about 250 centipoise, typically greater than about
500 centipoise, often greater than about 750 centipoise, and even
greater than about 1,000 centipoise, when present in a 3 percent by
weight solution (e.g., with water as a solvent) at 25.degree.
C.
[0048] Other representative polymeric agents, and representative
amounts of those polymeric agents employed in coating formulations,
are of the type set forth in US Pat. App. Pub. No. 2007/0246055 to
Oglesby, which is incorporated herein by reference.
[0049] The amount of film-forming agent within the coating
formulation may vary. Preferably, the amount of film-forming agent
is at least about 1 percent, generally at least about 5 percent,
and often at least about 10 percent; and typically does not exceed
about 30 percent, generally does not exceed about 25 percent, and
often does not exceed about 20 percent; based on the total weight
of the coating formulation prior to use (i.e., including the liquid
solvent or carrier of the formulation). Although the viscosity of
the formulation can vary, preferably, the film-forming agent
preferably acts to thicken the formulation to a viscosity of less
than about 100,000 centipoise, often about less than about 50,000
centipoise, when measured as a Brookfield viscosity (No. 6 spindle,
10 rpm, 25.degree. C.).
[0050] When employed, the amount of thickening agent within the
coating formulation may vary. The amount of thickening agent that
can be employed can be selected based upon factors such as the
desired rheological properties of the coating formulation, the
characteristics and properties of the other components of the
coating formulation (e.g., the thickening properties of the
film-forming agent components), the compatibility of the thickening
agent with the other components of the formulation, and the
thickening properties of the thickening agent that is selected.
Preferably, the amount of thickening agent is at least about 1
percent, generally at least about 5 percent, and often at least
about 10 percent; and typically does not exceed about 30 percent,
generally does not exceed about 25 percent, and often does not
exceed about 20 percent; based on the total weight of the coating
formulation prior to use (i.e., including the liquid solvent or
carrier of the formulation). Although the viscosity of the
formulation can vary, preferably, the thickening agent acts to
thicken the formulation to a viscosity of about 15,000 centipoise
to about 100,000 centipoise, preferably about 20,000 centipoise to
about 30,000 centipoise, as measured as a Brookfield viscosity (No.
6 spindle, 10 rpm, 25.degree. C.).
[0051] The coating formulation may incorporate other ingredients,
in addition to the aforementioned polymeric materials. Those other
ingredients can be dissolved within the liquid carrier of the
coating formulation, dispersed on, or suspended within that coating
formulation. Those other ingredients can be employed in order to
provide specific properties or characteristics to the wrapping
material.
[0052] For example, the coating formulation can incorporate
flavoring agents, humectants, sugars and sugar-type compounds
(e.g., sucrose, glucose, fructose, maltose, melezitose, dextrose,
lactose, galactose and mannose), syrups (e.g., high fructose corn
syrup and honey), wetting agents, defoaming agents, preservatives,
colorants or pigments, and the like. Though not necessarily
preferred, the coating formulation can incorporate water soluble
(e.g., sodium chloride, calcium chloride, potassium citrate, and/or
potassium chloride) and/or water insoluble (e.g., calcium carbonate
or magnesium oxide) fillers. Certain salts can act to enhance the
ability to remove liquid solvent or carrier of the additive
material formulation during drying operations. Other ingredients
can include catalytic materials (e.g., ultrafine particles or
nanoparticle types of materials), metals or metal oxides (e.g.,
iron oxide powder), ammonium salts or ammonia generating compounds,
or other types of ingredients that have the ability to alter the
chemical nature or character of tobacco smoke generated by the
cigarette. Preferably, the optional ingredients are essentially
chemically non-reactive with other components of the formulation,
at least under those conditions at which the formulation is
employed. Preferably, the optional ingredients are employed in
amounts that do not result in introduction of undesirable rheology
to the coating formulation (e.g., introducing an undesirably high
viscosity to the formulation). See, also, for example, the types of
ingredients, and amounts of those ingredients, set forth in U.S.
Pat. Application Pub. Nos. 2005/0016556 to Ashcraft et al. and
2005/0076929 to Fitzgerald et al.; and U.S. Pat. App. Pub. Nos.
2007/0084475 to Oglesby and 2007/0246055, to Oglesby; each of which
is incorporated by reference.
[0053] The oating formulation preferably is incorporated within a
suitable solvent, such as an aqueous liquid, to produce a coating
formulation that is considered to be a thickened mixture. Preferred
coating formulations can be considered to have a "paste-like"
consistency. A representative water-based coating formulation
having a solvent or carrier content of about 65 weight percent to
about 85 weight percent exhibits a Brookfield viscosity (No. 6
spindle, 10 rpm, 25.degree. C.) that is typically greater than
about 10,000 centipoise, often greater than about 20,000
centipoise, but usually less than about 800,000 centipoise, often
less than about 400,000 centipoise, and frequently less than about
200,000 centipoise; and preferably about 30,000 centipoise to about
100,000 centipoise.
[0054] The suitable solvent or liquid carrier of the coating
formulation most preferably is a liquid having an aqueous
character, and can include relatively pure water (e.g., tap water
or de-ionized water). If desired, organic solvents or liquid
carriers, such as alcohols, can be employed. Although not all
components of the coating formulation are necessarily soluble in
the liquid carrier, it is most preferable that the film-forming
components be soluble (or at least highly dispersible) in that
liquid. By "soluble" in referring to the components of the coating
formulation with respect to the liquid solvent, it is meant that
the components for a thermodynamically stable mixture when combined
with the solvent, have a significant ability to dissolve in that
solvent, and do not form precipitates to any significant degree
when present in that solvent.
[0055] Representative coating formulations typically incorporate
about 50 to about 90, generally about 65 to 85, weight percent
liquid carrier (e.g., an aqueous solution such as relatively pure
water, or a non-aqueous solution); about 10 to about 50, generally
about 15 to about 30, weight percent of the polymeric agent mixture
(e.g., the combined weight of the polymeric thickening, low
viscosity polymeric, and film-forming polymeric components); based
on the total weight of liquid carrier and polymeric agent mixture.
Preferably, other optional ingredients, such as the previously
described salts, preservatives, sugars, flavoring agents, and the
like, typically are incorporated within the coating formulation in
total amounts that are less than about 15, and usually less than
about 10 weight percent, based on the total weight of the coating
formulation prior to use.
[0056] The relative amounts of the various other optional
components of the coating formulation can vary. In many preferred
embodiments, the combined amounts of ingredients such as
flavorings, colorants, preservatives, fillers, and the like,
preferably do not exceed about 50 percent, often do not exceed 40
percent, and frequently do not exceed about 30 percent, of the
total combined weight of the film-forming agent components and
optional components.
[0057] Increasing the filler (CaCO.sub.3) content and decreasing
the basis weight of the wrapping paper material may reduce
per-cigarette carbon monoxide yields. Providing higher diffusion
capacities--even without significantly increasing CORESTA
values--may also reduce per-cigarette carbon monoxide yields. Net
diffusion capacity (the average diffusion capacity of coated/banded
and uncoated/unbanded regions) correlates to carbon monoxide
yields. In particular, cigarettes using paper with higher net
diffusion capacity generally will produce lower carbon monoxide
yields.
[0058] Coating formulations, such as the types of water-based
coating formulations described hereinbefore, are subjected to
drying conditions after those formulations have been applied to the
wrapping material, such as a continuous strip of paper web of
wrapping material. Preferably, sufficient solvent is removed from
the formulation after that formulation has been applied to the
wrapping material such that the additive material that remains in
contact with the wrapping material does not exhibit a sticky or
tacky character or nature. Preferably, sufficient solvent (e.g.,
water or a non-aqueous solvent) is removed from the formulation
after it has been applied to the wrapping material such that the
additive material that remains in contact with the wrapping
material exhibits a solvent (e.g., moisture) content of less than
about 10 percent, more preferably less than about 8 percent, based
on the weight of the coating formulation that remains in contact
with the wrapping material. Preferably, sufficient solvent (e.g.,
water or a non-aqueous solvent) is removed from the formulation
after that formulation has been applied to the wrapping material
such that the formulation that remains in contact with the wrapping
material exhibits a solvent (e.g., moisture) content of about 4
percent to about 6 percent, based on the weight of the coating
formulation that remains in contact with the wrapping material.
[0059] The amount of coating formulation that is applied to the
wrapping material may vary. The coating formulation preferably is
applied to the wrapping material such that the dry weight of the
additive material on the wrapping material is least about 1
g/m.sup.2, often at least about 2 g/m.sup.2, and frequently at
least about 3 g/m.sup.2. The coating formulation may be applied to
the wrapping material such that the dry weight of the additive
material on the wrapping material is less than about 10 g/m.sup.2,
often is less than about 7 g/m.sup.2, and frequently is less than
about 4 g/m.sup.2. For example, a paper wrapping material having a
dry basis weight of about 25 g/m.sup.2 can be coated with coating
formulation and dried to have a resulting overall dry basis weight
in the coated regions of about 27 g/m.sup.2 to about 28.5
g/m.sup.2.
[0060] Coated regions of the wrapping material useful as the
circumscribing wrapper of tobacco rods for cigarettes are produced
using additive materials that are effective in reducing the
porosity of the wrapping material in those regions. Film-forming
materials coated onto the wrapping material have a tendency to
reduce the porosity of the wrapping material. Typical coated
regions of the wrapping materials have porosities that can vary.
Preferably, the porosities of the coated regions of the wrapping
materials are less than about 9 CORESTA, and usually are less than
about 8 CORESTA. Preferably, the porosities of the coated regions
of the wrapping materials are at least about 0.1 CORESTA, usually
are at least about 1 CORESTA unit, and often are at least about 3
CORESTA units. Preferably, the porosities of the coated regions of
the wrapping materials, particularly those wrapping materials that
are used for the manufacture of cigarettes designed to meet certain
cigarette extinction test criteria, are from about 3 CORESTA to
about 6 CORESTA.
[0061] The wrapping material can include patterns of predetermined
shapes and sizes positioned at predetermined locations, and hence,
cigarettes appropriately manufactured from that wrapping material
can include coated patterns of predetermined shapes and sizes
positioned at predetermined locations on their smokable rods.
Representative patterns are set forth in U.S. Pat. Application Pub.
Nos. 2005/0016556 to Ashcraft et al.; and 2005/0076929 to
Fitzgerald et al. For example, shapes of coated regions,
compositions of the coating formulations, or amounts or
concentrations of coating materials, can change over the length of
the wrapping material. The relative positioning of the printed
regions can be selected as desired. For example, wrapping materials
that are used for the production of cigarettes designed to meet
certain cigarette extinction test criteria, the pattern most
preferably has the form of spaced continuous bands that are aligned
transversely or cross directionally to the longitudinal axis of the
wrapping material. Cross-directional lines or bands that are
essentially perpendicular to the longitudinal axis of the wrapping
material preferably extend sufficiently across the wrapping
material such that smokable rods manufactured from that wrapping
material have bands that completely or nearly completely
circumscribe the smokable rods. A cigarette also can be
manufactured from a wrapping material including discontinuous bands
positioned in a spaced apart relationship. For a wrapping material
of such a cigarette, it is most preferred that discontinuous bands
(e.g., bands that include a pattern, such as a series of dots,
grids or stripes) cover at least about 70 percent of the surface of
the band area or region of the wrapping material. A cigarette also
can be manufactured from a wrapping material including at least one
longitudinally extending stripe, which stripe is provided by a
coating formulation, such as a coating formulation of the present
invention.
[0062] Preferred wrapping materials include coatings in the form of
bands that extend across the wrapping material, generally
perpendicular to the longitudinal axis of the wrapping material.
The widths of the individual bands can vary, as well as the spacing
between those bands. Preferably, those bands have widths of at
least about 2 mm, usually at least about 3 mm, frequently at least
about 4 mm. However, the bands may have widths of up to about 8 mm.
Preferred bands have widths of about 4 mm to about 7 mm, and often
have widths of about 6 mm to about 7 mm. Such bands can be spaced
apart such that the spacing between the bands (i.e., as measured
from the inside adjacent edges of the bands) is at least about 10
mm; but which may be about 15 mm, 20 mm, or 25 mm, in certain
instances at least about 30 mm, and on occasion at least about 35
mm; but such spacing preferably does not exceed about 50 mm. For
certain preferred wrapping materials, the bands are spaced apart
such that the spacing between the bands is about 15 mm to about 25
mm, more preferably about 18 mm to about 24 mm.
[0063] Preferably, the coating formulation has an overall
composition, and is applied in a manner and in an amount, such that
the physical integrity of the wrapping material is not adversely
affected when the coating formulation is applied to selected
regions of the wrapping material. It is desirable that the
components of the coating formulation applied to wrapping materials
not adversely affect to any significant degree (i) the appearance
of cigarettes manufactured from those wrapping materials, (ii) the
nature or quality of the smoke generated by those cigarettes, (iii)
the desirable burn characteristics of those cigarettes, or (iv) the
desirable performance characteristics of those cigarettes.
Specifically, it is desirable that components of the coating
formulation not introduce undesirable sensory characteristics to
the smoke generated by a smoke article incorporating a wrapping
material treated with that coating formulation. For preferred
cigarettes, it is desirable that the coating formulation applied to
the wrapping material provide the desirable extinction performance
characteristics to the cigarettes manufactured using that wrapping
material at relatively low coating or application levels. For
example, for cigarettes evaluated for self-extinction properties
using the type to test method set forth in ASTM Designation: E
2187-02b using 10 layers of Whatman No. 2 filter paper, extinction
criteria most preferably are met for 100 percent of the cigarettes
tested when about 2.5 g/m.sup.2 to about 3.5 g/m.sup.2 of preferred
dry coating is applied as bands that extend around the cigarette
rod and are spaced along the length of the cigarette rod.
[0064] A preferred wrapping material includes a coated region
exhibiting a diffusion capacity in that coated region when measured
at ambient temperature that is relatively low, but exhibits a
diffusion capacity in the coated region--when measured after being
subjected to exposure to a temperature significantly above ambient
temperature--that is relatively high. For example, ratios of
diffusion capacities for a heated coated region to an unheated
coated region of a wrapping material (e.g., for a wrapping material
heated at about 230.degree. C. for an effective period of time and
cooled to ambient for measurement, relative to a wrapping material
maintained and measured at ambient temperature) can be greater than
about 3:1, and often can be greater than about 5:1. See, U.S.
Patent Application Pub. No. 2005/0087202 to Norman et al. and
Norman et al., Beitr. Tabakforsch. Int. 21 (2205) 425-434, each of
which is incorporated by reference.
[0065] A preferred embodiment of a wrapping material includes one
or more bands of a coating formulation of the present invention.
When measured at ambient temperature, each portion of the wrapping
material that is a coated region or a region occupied by a band of
the coating formulation preferably exhibits a diffusion capacity of
less than about 0.2 cm/sec, more preferably less than about 0.1
cm/sec, and sometimes less than about 0.09 cm/sec. After being
heated substantially above ambient temperature, (preferably at
about 230.degree. C.) for about 15 minutes, and cooled to ambient
temperature for measurement, each coated region or region occupied
by a band of the coating formulation preferably exhibits, for
certain preferred formulations, a diffusion capacity of at least
about 0.5 cm/sec, and more preferably at least about 0.7
cm/sec.
[0066] A preferred smoking article in the form of cigarette
incorporating a tobacco rod manufactured from wrapping material
treated with the additive material formulation of the present
invention meets extinction criteria while also exhibiting a
propensity to avoid self-extinction during normal smoking
conditions. That is, a preferred cigarette, while being capable of
meeting the certain extinction criteria, does not experience free
air self-extinction to a significant degree, and most preferably
there is a low rate of occurrence of free air self-extinction. For
example, a preferred cigarette generally will not have a tendency
to undergo premature extinction, such as when lit cigarettes are
held in the smoker's hand or when placed in an ashtray for a brief
period of time. Preferred cigarettes may undergo free air
self-extinction for less than about 30 percent, preferably for less
than about 15 percent, and most preferably for 0 percent, of
cigarettes tested. Free air self-extinction with regards to a
cigarette having a tobacco rod incorporating a wrapping material
including circumscribing bands of additive material relates to
those burning cigarette rods that extinguish when left to burn in
air (and not in contact with a substrate).
[0067] In one embodiment, a base wrapping material is provided,
having an inherent porosity of about 120 CORESTA. A surface of the
base wrapping material is treated with an ash conditioner
consisting essentially of potassium citrate (and excluding sodium
citrate). The potassium citrate is treated so as to be present on a
dry weight basis at about 0.4% to about 1%. The diffusion capacity
of the treated base paper may be about 1.6 cm/sec to about 2.2
cm/sec, or it may exceed 2.2 cm/sec; it may generally be at least
about 1.7 cm/sec, may often be at least about 1.9 cm/sec, may be at
least about 2 cm/sec, and may sometimes be at least about 2.1
cm/sec, while it may be provided at about 2.2 cm/sec or more.
Smoking articles constructed with a base wrapping material having
these characteristics showed reduced carbon monoxide yields.
[0068] A banded region of the base material may include starch such
as, for example, chemically cross-linked, mechanically fragmented
starch, applied in a manner configured to provide a desirable
self-extinction profile. See, e.g., U.S. Pat. App. Pub. No.
2009/0266371 to Fritzsching. Alternatively, or in addition, it may
be configured to include more or different polymeric materials as
disclosed herein and/or as otherwise known in the art.
[0069] In one example, a sampling of base wrapping materials was
provided, being constructed with wood pulp fiber furnish and
calcium carbonate at 30% by weight as a filler with an inherent
porosity of about 120 CORESTA (from a range of 118.9 to 127.7; all
values in this example being averaged across samples from the
materials, with range boundaries being identified). The basis
weight of the paper was 26 gsm (no variance across sample range),
and it was treated with potassium citrate only as an ash
conditioner (excluding sodium citrate). Its average base diffusion
capacity was about 1.78 cm/sec (from a range of 1.67 to 1.89
cm/sec). The paper was an FSC paper banded with treated/
reduced-diffusion regions that were 6.5 mm wide, spaced apart 18.5
mm, with 26% band coverage (6.5 mm/25 mm) with an average diffusion
capacity in the banded regions of about 0.1 cm/sec, where the
banding material included starch. Smoking articles constructed with
the wrapping material exhibited 100% ASTM SE. Notably, the smoking
articles exhibited a reduction in mainstream carbon monoxide
averaging 10.5% and a reduction of CO/Nicotine averaging 8.4%, each
being measured under the FTC Smoking Regimen conditions (which are
no longer designated as such by the FTC).
[0070] Those of skill in the art will appreciate that other
embodiments of may be practiced within the scope of the present
invention. It is therefore intended that the foregoing detailed
description be regarded as illustrative rather than limiting, and
that it be understood that it is the following claims, including
all equivalents, that are intended to define the spirit and scope
of this invention.
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