Note: Descriptions are shown in the official language in which they were submitted.
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HIGH STRENGTH WRAPPING MATERIAL CONTAINING
EXTRACTED TOBACCO
RELATED APPLICATIONS
[0001] The present application is based upon and claims
priority to U.S.
Provisional Patent Application Serial No. 63/155,518, having a filing date of
March 2, 2021, and which is incorporated herein by reference.
BACKGROUND
[0002] Various different aerosol generating products exist
that generate an
aerosol for enjoyment by a user. Such products include, for instance, smoking
articles, heat but not burn sticks, and the like. Aerosol generating products
typically include an aerosol generating filler in the shape of a rod that is
covered by
an outer wrapper.
[0003] Traditionally, outer wrappers for aerosol generating
products have been
made from papermaking fibers, such as pulp fibers. The use of papermaking
fibers, for instance, provides a wrapper that has sufficient strength to be
fed
through high speed machinery used to produce the aerosol generating products.
[0004] Although papermaking fibers provide various advantages
when
producing wrapping materials for aerosol generating products, such as smoking
articles, papermaking fibers can negatively affect the overall taste of the
product.
Thus, in the past, those skilled in the art have attempted to incorporate
tobacco
materials into wrapping papers. Incorporating significant amounts of tobacco
material into wrapping papers, however, negatively impacts the strength of the
product. In particular, wrapping papers made in the past containing
substantial
amounts of tobacco material have not displayed sufficient strength to be used
in
high speed machines, such as cigarette making machines.
[0005] In view of the above, a need exists for a wrapping
material containing
substantial amounts of tobacco that has sufficient strength for use in
constructing
aerosol generating products.
SUMMARY
[0006] In general, the present disclosure is directed to a
wrapping material for
an aerosol generating product that is made from a tobacco material. More
particularly, the present disclosure is directed to a high strength wrapping
material
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containing substantial amounts of a tobacco material. The wrapping material of
the present disclosure can be used to produce all different types of products,
including cigarettes and other smoking articles, heat but not burn sticks, and
the
like.
[0007] In one embodiment, for example, the present disclosure
is directed to a
wrapping material for covering an aerosol producing filler. The wrapping
material
includes a web comprising at least about 40% by weight of an extracted tobacco
material. The extracted tobacco material is blended with strength building
fibers.
The strength building fibers comprise refined bast fibers. The refined bast
fibers
have an average fiber length of less than about 4 mm. The wrapping material
has
a basis weight of from about 15 gsm to about 45 gsm.
[0008] In certain aspects, the web can contain at least about
50% by weight,
such as at least about 60% by weight, such as at least about 70% by weight,
such
as at least about 80% by weight extracted tobacco material. The tobacco
material
is extracted such that the tobacco material and/or the web has a water soluble
content of less than about 20% by weight, such as less than about 17% by
weight,
such as less than about 15% by weight, such as less than about 12% by weight,
such as less than about 10% by weight, such as less than about 8% by weight.
The refined bast fibers can comprise hemp fibers and can be present in the web
in
an amount greater than about 10% by weight, such as in an amount greater than
about 12% by weight, such as in an amount greater than about 14% by weight,
such as in an amount greater than about 16% by weight. In one aspect, the
refined bast fibers are also bleached.
[0009] In accordance with the present disclosure, the
wrapping material can
have a tensile strength when measured according to ASTM Test D828-97 of
greater than about 2,100 cN/30 mm, such as greater than about 2,200 cN/30 mm,
such as greater than about 2,300 cN/30 mm, such as greater than about 2,400
cN/30 mm, and generally less than about 3,400 cN/30 mm. The wrapping material
can also have a stretch of greater than about 1%, such as greater than about
1.2%, such as greater than about 1.5% when measured according to ISO Test
1924 (2008).
[0010] Optionally, the wrapping material can also contain
wood pulp fibers. The
wood pulp fibers, for instance, can be softwood fibers, hardwood fibers, or
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mixtures thereof. Wood pulp fibers can be present in the web in an amount up
to
about 10% by weight, and generally in an amount less than about 8% by weight,
such as in an amount less than about 6% by weight.
[0011] In one aspect, the tobacco material contained in the
wrapping material
has been fed through an extraction process for removing water soluble
components and has also been refined. In one embodiment, however, the tobacco
material has not been fed through a pulping process, which refers to combining
the
tobacco material with a base, such as sodium hydroxide, and cooked in a
digester.
Of particular advantage, the use of the refined bast fibers allows for the use
of
extracted but non-pulped tobacco fibers while still providing sufficient
strength and
formation properties.
[0012] In one aspect, the wrapping material has a basis
weight of from about 25
gsm to about 38 gsm. The wrapping material can have a permeability of from
about 5 Coresta to about 80 Coresta, such as from about 8 Coresta to about 38
Coresta. The wrapping material can optionally contain a filler. For example,
in
one embodiment, the wrapping material contains no filler particles.
Alternatively,
filler particles can be present in the wrapping material in an amount from
about
0.5% by weight to about 30% by weight, such as from about 1% by weight to
about
12% by weight.
[0013] In one aspect, the wrapping material can be treated
with a burn control
agent for better control of the burn properties. For instance, the burn
control agent
can comprise a salt of a carboxylic acid, such as a citrate or a succinate.
The burn
control agent can be present on the wrapping material in an amount from about
0.3% by weight to about 3% by weight, such as in an amount from about 1% by
weight to about 2% by weight.
[0014] The wrapping material can also be treated with a
humectant and/or a
gum. The humectant, for instance, can comprise glycerol, propylene glycol, or
mixtures thereof. The gum, on the other hand, can comprise guar gum, an
alginate, carboxymethyl cellulose, or mixtures thereof. The gum can be present
on
the wrapping material in an amount from about 0.1% by weight to about 2% by
weight.
[0015] VVhen used in smoking articles, the wrapping material
can also optionally
include a plurality of discrete reduced ignition areas spaced along a first
direction
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of the wrapping material. The reduced ignition areas can have a diffusivity of
less
than about 0.5 cm/s at 23 C. The plurality of reduced ignition areas can be
formed
by applying a reduced ignition composition to the web. The reduced ignition
composition, for instance, can comprise cellulose fibers, a film forming
material, or
mixtures thereof.
[0016] Other features and aspects of the present disclosure
are discussed in
greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] A full and enabling disclosure of the present
disclosure is set forth more
particularly in the remainder of the specification, including reference to the
accompanying figures, in which:
Figure 1 is a perspective view of one embodiment of an aerosol
generating product incorporating the wrapping material of the present
disclosure;
and
Figure 2 is an exploded view of the aerosol generating product
illustrated in Figure 1.
[0018] Repeat use of reference characters in the present
specification and
drawings is intended to represent the same or analogous features or elements
of
the present invention.
DEFINITIONS
[0019] As used herein, an "aerosol generating material" is
meant to include
both a combustible material that undergoes combustion in a smoking article and
to
an aerosol-forming material that is heated but not combusted to form an
inhalable
aerosol. Combustible smoking articles can include cigarettes, cigarillos and
cigars,
pre-rolled cones etc. In a cigarette, the aerosol generating material is
generally
surrounded by a wrapping material to form a smokable rod. Aerosol generating
devices for generating an aerosol include, for instance, devices in which an
aerosol is generated by electrical heating or by the transfer of heat from a
combustible fuel element or heat source to heat but not burn the aerosol
generating material, which releases volatile compounds. As the released
compounds cool, they condense to form an aerosol that is inhaled by the
consumer.
[0020] As used herein, "extracted tobacco fibers" refers to
tobacco fibers that
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have been subjected to an extraction process in which the tobacco has been
contacted with an aqueous solution to remove greater than 40%, such as greater
than 50%, such as greater than 60%, such as greater than 70%, such as greater
than 75% of the water soluble components contained in the tobacco. The
extraction process is from a delignification process and from a bleaching
treatment.
[0021] As used herein, "delignified" cellulosic fibers refers
to fibers that have
been subjected to a pulping or delignification process by which the cellulose
fibers
are separated from the plant material through chemical means, mechanical
means, or through a combination of chemical and mechanical means.
[0022] As used herein, the term "refine" is used to mean that
the plant material
is subjected to a mechanical treatment that modifies the fibers of the
material so
that they are better suited to forming a fibrous sheet or substrate. Refining
can be
accomplished using a conical refiner or a disks refiner or a Valley beater.
The
mechanical process exerts an abrasive and bruising action on the plant
material
such that the plant material is defibrillated. Refining is a different process
than
delignification and pulping.
[0023] As used herein, the "amount of water soluble extracts"
present in a
substrate or reconstituted plant material or in an aerosol-generating material
is
determined by taking 5 grams of a sample in boiling distilled water for 10
minutes
to obtain an extract containing water soluble components. The weight of dry
matter of the extract that is soluble in the solvent is calculated by the
difference
between the dry weight of the sample and the dry weight of the sample after
extraction. The difference in dry weight is then used to determine the
percentage
of water soluble extracts in the sample.
DETAILED DESCRIPTION
[0024] It is to be understood by one of ordinary skill in the
art that the present
discussion is a description of exemplary embodiments only and is not intended
as
limiting the broader aspects of the present disclosure.
[0025] The present disclosure is generally directed to a
wrapping material for
an aerosol generating product that is formed from a web that includes
extracted
tobacco fibers combined with strength building fibers. The strength building
fibers
comprise refined bast fibers, such as hemp fibers. In accordance with the
present
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disclosure, the wrapping material can contain a tobacco material in amounts
greater than 40% by weight and still have sufficient strength and other
properties
needed for mass producing aerosol generating products, such as smoking
articles,
heat but not burn sticks, and the like.
[0026] The high amount of tobacco fibers contained in the
wrapping material
creates a natural and pleasant tobacco taste when consumed in an aerosol
producing product. In addition, the tobacco material is extracted by removing
water soluble components. Removing the water soluble components can remove
undesirable components. In one aspect, the water soluble components can be
optionally concentrated and/or filtered and reapplied. In another aspect,
flavorants
can be applied to the wrapping material. Due to the mechanical properties, the
wrapping material of the present disclosure also has great runnability
characteristics on conventional cigarette making machines. The wrapping
material
of the present disclosure can be used to produce all different types of
aerosol
generating products, such as cigarettes, cigarillos, and the like. The
wrapping
material can also be combined with substantial amounts of a humectant for use
in
heat but not burn applications.
[0027] In addition to the above advantages, the wrapping
material of the
present disclosure also has excellent aesthetic properties. For instance, the
wrapping material can have a visual association with a tobacco identity due to
the
great amounts of tobacco material that are contained in the product. In
addition,
the wrapping material can be treated with a coloring agent, such as a dye, in
order
to further enhance a natural tobacco look.
[0028] As described above, the wrapping material of the
present disclosure
includes a blend of an extracted tobacco material and strength building
fibers.
Optionally, the wrapping material may also contain pulp fibers and/or filler
particles.
[0029] The tobacco materials that can be used to produce the
wrapping
material can include any suitable type of tobacco furnish. The tobacco
furnish, for
instance, can contain tobacco stems, such as flue-cured stems, leaves, fines,
and/or other tobacco by-products. In accordance with the present disclosure,
the
tobacco material can be subjected to an extraction process for removing water
soluble components. Specifically, the compounds naturally present in the
tobacco
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material that are soluble in a solvent, such as water, may give rise to
problems,
such as during making of the wrapping material or later during the making of
aerosol generating products. Consequently, the tobacco materials incorporated
into the wrapping material are preferably subjected to an extraction process.
The
extraction process may include placing the tobacco materials in water and
allowing
the water soluble portions to be extracted into the water. In an alternative
embodiment, various solvents that are water-miscible, such as alcohols (e.g.,
ethanol), and/or suitable oils and fats, can be combined with water to form an
aqueous solvent. The water content of the aqueous solvent can, in some
instances, be greater than about 50% by weight, such as greater than about 90%
by weight of the solvent. Deionized water, distilled water, or tap water may
be
employed. The amount of the solvent in the tobacco material suspension can
vary
widely, but is generally added in an amount from about 50% by weight to about
99% by weight, such as from about 60% by weight to about 95% by weight, and,
in
one aspect, from about 75% by weight to about 90% by weight of the suspension.
In one embodiment, the solvent may be heated prior to or during contact with
the
tobacco materials. For example, in one aspect, the extraction solution may be
a
hot aqueous solution.
[0030] The tobacco material and solvent can optionally be
agitated by stirring,
shaking, or otherwise mixing the suspension in order to increase the rate of
solubilization. Typically, the process can be carried out for about ten
minutes to
about six hours. Process temperatures may range from about 10 C to about
100 C, such as from about 23 C to about 80 C. In one aspect, the temperature
of
the suspension can be from about 40 C to about 80 C.
[0031] After the tobacco materials are soaked and optionally
agitated, the
insoluble portion of the tobacco material can be mechanically separated from
the
soluble portion of the tobacco material using a press or a centrifuge or any
other
suitable device or method. Once the soluble fraction is separated from the
insoluble fraction, the soluble fraction can be discarded or further
processed, such
as by being concentrated. The soluble fraction can be concentrated using any
known type of concentrator, such as a vacuum evaporator. In some applications,
the water soluble fraction can be discarded or used in other processes.
However,
if desired, a portion or all of the soluble fraction can be concentrated and
reapplied
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to the web formed from the extracted tobacco materials.
[0032] The extraction process carried out on the tobacco
material removes
soluble compounds which facilitates the processing of the tobacco material
into a
web. The extraction process can also be used to remove undesired compounds.
For instance, through the extraction process, various different components,
such
as nitrosamines, may be removed from the tobacco material. The extraction
process can also remove, if desired, nicotine.
[0033] The resulting water insoluble, extracted tobacco
material is generally in
an unrefined state. The tobacco material can comprise particles and fibers. In
one
embodiment, the insoluble and extracted tobacco material can optionally be
subjected to a refining process. For instance, the extracted tobacco material
can
be fed through any suitable refining device, such as a conical refiner or a
disk
refiner. Other refining devices that may be used include a beater, such as a
Valley
beater. Refining can occur while the tobacco materials are moist or after
being
combined with water. For instance, in one embodiment, refining can occur while
the tobacco material is at a consistency of less than about 10%, such as less
than
about 5%, such as less than about 3%.
[0034] The extracted and refined tobacco materials, in one
aspect, can contain
a relatively low amount of water soluble components. For instance, the
extracted
tobacco material can contain water soluble components in an amount less than
about 30% by weight, such as in an amount less than about 20% by weight, such
as in an amount less than about 17% by weight, such as in an amount less than
about 15% by weight, such as in an amount less than about 12% by weight, such
as in an amount less than about 10% by weight, such as in an amount less than
about 8% by weight, such as in an amount less than about 6% by weight and
generally greater than about 2% by weight. As described above, optionally the
water soluble components can be concentrated, otherwise treated, and reapplied
to the web formed from the tobacco material. In one preferred embodiment,
however, the water soluble components are not reapplied to the extracted
tobacco
materials.
[0035] In accordance with the present disclosure, the
extracted tobacco
material or tobacco fibers are combined with strength building fibers,
particularly
refined bast fibers. The extracted tobacco fibers can be non-pulped meaning
that
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the fibers have not been fed through a pulping process in which the fibers are
combined with an alkaline material (Kraft process) or an acid material
(Sulfite
process) and cooked in a digester. The strength building fibers, on the other
hand,
can be pulped or delignified. In one aspect, the extracted tobacco material
can be
combined with water or an aqueous solution to form a slurry. The strength
building
fibers, such as delignified cellulosic bast fibers, can be combined with the
tobacco
material in forming the slurry. The fiber slurry is then used to form a
continuous
web that has the characteristics of paper. For example, in one embodiment, the
fiber slurry can be fed to a papermaking process that can include a forming
wire,
gravity drain, suction drain, a felt press, and a dryer, such as a Yankee
dryer, a
drum dryer or the like. In one aspect, the fiber slurry is formed into a
continuous
sheet on a Fourdrinier table.
[0036] The fiber slurry containing the extracted tobacco
material and the
strength building fibers, for instance, can be laid onto a porous forming
surface and
formed into a sheet. Excess water can be removed by a gravity drain and/or a
suction drain. In addition, various presses can be used to facilitate water
removal.
The formed sheet can be dried and further treated.
[0037] As described above, the strength building fibers are
refined bast fibers.
The bast fibers can also be pulped or delignified and/or bleached. Examples of
bast fibers that may be used in the present disclosure include hemp fibers,
flax
fibers, abaca fibers, ramie fibers, cotton fibers, bamboo fibers, esparto
fibers, and
mixtures thereof. The bast fibers can be highly refined using, for instance, a
Dutch
Valley Beater. In one particular embodiment, the bast fibers are hemp fibers
alone
or in combination with other bast fibers.
[0038] As described above, the bast fibers can be highly
refined. The bast
fibers can have an average fiber length of generally greater than about 0.5
mm,
such as greater than about 0.8 mm, such as greater than about 1 mm, such as
greater than about 1.2 mm, such as greater than about 1.5 mm. The average
fiber
length of the refined bast fibers is generally less than about 4 mm, such as
less
than about 3.6 mm, such as less than about 3.3 mm, such as less than about 3
mm, such as less than about 2.8 mm, such as less than about 2.5 mm, such as
less than about 2.3 mm, such as less than about 2.1 mm. In one particular
aspect,
the bast fibers can be delignified hemp fibers having an average fiber length
of
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from about 1.5 mm to about 2 mm.
[0039] Optionally, the web formed according to the present
disclosure can also
contain wood pulp fibers and/or botanical fibers. The wood pulp fibers, for
instance, can comprise delignified fibers, such as softwood fibers, hardwood
fibers,
or mixtures thereof.
[0040] The extracted tobacco material, strength building
fibers, and optionally
wood pulp fibers can be combined together in order to form a web. In one
aspect,
the fibers are all combined together in an aqueous suspension and used to form
a
web through a wetlaid process. In this manner, a substantially homogeneous
fiber
distribution is achieved. The amount of each fiber contained in the resulting
web
can vary. In general, the web formed according to the present disclosure
contains
extracted tobacco material in an amount greater than about 40% by weight and
in
an amount up to about 90% by weight, including all increments of 1% by weight
therebetween. For example, the extracted tobacco material can be contained in
the web in an amount greater than about 45% by weight, such as in an amount
greater than about 50% by weight, such as in an amount greater than about 55%
by weight, such as in an amount greater than about 60% by weight, such as in
an
amount greater than about 65% by weight, such as in an amount greater than
about 70% by weight, such as in an amount greater than about 75% by weight,
such as in an amount greater than about 80% by weight, such as in an amount
greater than about 85% by weight. The extracted tobacco material can be
contained in the web in an amount less than about 80% by weight, such as in an
amount less than about 75% by weight, such as in an amount less than about 70%
by weight.
[0041] The strength building fibers can be present in the web
generally in an
amount up to about 50% by weight. The strength building fibers are generally
present in the web in an amount greater than about 5% by weight, such as in an
amount greater than about 10% by weight, such as in an amount greater than
about 15% by weight, such as in an amount greater than about 17% by weight,
such as in an amount greater than about 20% by weight, such as in an amount
greater than about 23% by weight, such as in an amount greater than about 25%
by weight, such as in an amount greater than about 28% by weight, such as in
an
amount greater than about 30% by weight. The strength building fibers are
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generally present in an amount less than about 35% by weight, such as in an
amount less than about 30% by weight, such as in an amount less than about 25%
by weight, such as in an amount less than about 20% by weight. As described
above, in one embodiment, the strength building fibers are refined hemp
fibers.
[0042] Wood pulp fibers can optionally be present in the web.
In one aspect,
for instance, the web can be produced without any wood pulp fibers. In other
embodiments, however, the wood pulp fibers can be present in an amount up to
about 12% by weight, such as in an amount up to about 10% by weight, such as
in
an amount up to about 8% by weight. The wood pulp fibers can generally be
present in an amount greater than about 2% by weight, such as in an amount
greater than about 5% by weight, such as in an amount greater than about 7% by
weight. In one particular aspect, the wood pulp fibers and the extracted
tobacco
fibers can be preblended and then later combined with the strength building
fibers.
For instance, the extracted tobacco material and wood pulp fibers can be
preblended at a weight ratio of from about 85:15 to about 95:5 and then
combined
with the strength building fibers.
[0043] In one aspect, the extracted tobacco material,
strength building fibers,
and optionally wood pulp fibers can be combined together and refined together
prior to forming the web. Alternatively, each fiber can be refined separately.
In still
another embodiment, each fiber can be refined separately, combined together,
and
then refined a further amount.
[0044] Optionally, the web can also contain filler particles.
Filler particles that
can be used include carbonate particles, oxide particles, and mixtures
thereof.
Particular filler particles include, for instance, calcium carbonate
particles,
magnesium oxide particles and mixtures thereof. Filler particles can be
present in
the web generally in an amount from about 0.5% by weight to about 30% by
weight, including all increments of 0.5% therebetween. For instance, filler
particles
can be present in an amount greater than about 1% by weight, such as in an
amount greater than about 2% by weight, such as in an amount greater than
about
5% by weight, and generally in an amount less than about 25% by weight, such
as
in an amount less than about 20% by weight, such as in an amount less than
about 15% by weight, such as in an amount less than about 12% by weight, such
as in an amount less than about 8% by weight. In one aspect, filler particles
can
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be present in an amount from about 0.5% by weight to about 5% by weight, such
as from about 0.5% by weight to about 2% by weight when the web contains
extracted tobacco material in an amount of about 50% by weight or greater. In
another aspect, the web can be completely free of any filler particles,
particularly
alumina particles or other aluminum-containing filler particles.
[0045] Although the web may contain filler particles, in one
aspect, the web is
primarily made from fibers, such as tobacco fibers, strength building fibers,
and
optionally pulp fibers. For instance, the fiber content of the web can be
greater
than about 90% by weight, such as greater than about 92% by weight, such as
greater than about 95% by weight, and generally less than about 99% by weight,
such as less than about 98% by weight, such as less than about 97% by weight.
[0046] As described above, the extracted tobacco material is
combined with the
strength building fibers and formed into a web, in one aspect, using a wet lay
process. Webs made according to the present disclosure have good strength, are
smooth, and can be formed to have optimum basis weight and permeability. Thus,
a wrapping material made according to the present disclosure is capable of
withstanding a papermaking process as well as the mechanical stress of mass
production of smoking articles, while also having improved sensory
characteristics
and burn properties.
[0047] For instance, wrapping materials made in accordance
with the present
disclosure have excellent mechanical characteristics and have a very desirable
and aesthetic appearance. In general, the wrapping material has a basis weight
of
greater than about 15 gsm, such as greater than about 18 gsm, such as greater
than about 20 gsm, such as greater than about 23 gsm, such as greater than
about 25 gsm. The basis weight of the wrapping material is generally less than
about 100 gsm, such as less than about 50 gsm, such as less than about 45 gsm,
such as less than about 43 gsm, such as less than about 40 gsm, such as less
than about 38 gsm, or any ranges therebetween. Within the above basis weights,
the wrapping material is very strong and can exhibit a tensile strength of
greater
than about 2,100 cN/30 mm, such as greater than about 2,200 cN/30 mm, such as
greater than about 2,300 cN/30 mm, such as greater than about 2,400 cN/30 mm,
and generally less than about 4,000 cN/30 mm. Tensile strength can be measured
using ASTM Test D828-97.
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[0048] In addition to relatively high tensile strength, the
wrapping material can
also have excellent stretch properties. For instance, the wrapping material
can
display a stretch of greater than about 1cY0, such as greater than about 1.2%,
such
as greater than about 1.4%. The stretch of the wrapper is generally less than
about 4%, such as less than about 2%.
[0049] The wrapping material according to the present
disclosure may also
have a permeability that facilitates suitable smoking properties, such as good
mainstream smoke control or good smoking comfort. For instance, the wrapping
material according to the present disclosure may have a permeability measured
in
Coresta units of from below detectable limits (i.e. 0 Coresta) to about 100
Coresta,
such as from about 5 Coresta to about 80 Coresta, such as from about 8 Coresta
to about 38 Coresta, or any ranges therebetween. The permeability can be
greater than about 8 Coresta, such as greater than about 10 Coresta, such as
greater than about 15 Coresta, such as greater than about 20 Coresta, such as
greater than about 25 Coresta, and generally less than about 65 Coresta, such
as
less than about 55 Coresta, such as less than about 45 Coresta. The above
permeability characteristics refer to the inherent permeability of the paper
meaning
the permeability of the paper without subjecting the paper to any treatments,
such
as perforating, that changes the permeability characteristics.
[0050] While the wrapping material according to the present
disclosure may
naturally or inherently have a desired permeability, in one embodiment, it may
be
desirable to also perforate the wrapping material after formation. Perforation
may
be performed as known in the art, and the number and size of the perforations
may
be selected as needed for the desired application.
[0051] In addition to the above physical properties, the
wrapping material made
in accordance with the present disclosure can exhibit a distinct natural
appearance
with natural speckling and/or coloration from the one or more tobacco fibers
or
particles. Optionally, the wrapping material may be formulated with pigments
(natural or synthetic) to adjust its final coloration. For instance, a
coloring agent,
such as a dye, may be applied to the fibers in a head box in an aqueous
solution
or applied to the web using a size press during formation of the web and prior
to
drying_ In one aspect, for instance, one or more coloring agents may be used
that
provide the web with a natural tobacco color, such as a brown color.
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[0052] Furthermore, in addition to having a natural
appearance, the wrapping
material according to the present disclosure may also have a pleasant texture.
The
wrapping material can have a relatively rough surface, which emphasizes its
natural appearance or can be further calendared to provide a smoother feeling.
[0053] The wrapping material of the present disclosure may
also be used to
produce smoking articles having better taste and sensory properties. For
instance,
the wrapping material of the present disclosure produces a less papery taste
than
conventional smoking papers. Instead, a pleasant neutral or distinct, natural
tobacco taste has been observed, even when the wrapping material contains
cellulosic strength building fibers. In one aspect, one or more flavorants can
also
be applied to the fibers and/or to the web during or after formation of the
web.
Flavorants can include sweetening agents, terpenes or the like.
[0054] Wrapping materials made according to the present
disclosure can be
incorporated into all different types of smoking articles and aerosol-
generating
products. For illustrative purposes only, one such smoking article is shown in
Figs.
1 and 2. As shown, the smoking article 10 includes a smokable column 12. The
smokable column 12, for instance, can be in the shape of a cylindrical rod
comprising an aerosol producing filler. The smoking article 10 may also
include a
wrapping material 100 that defines an outer circumferential surface 16 when
wrapped around the smokable column 12. The wrapping material 100 can include
overlapping edges 114 and 116 that are sealed together. The article 10 may
also
include a filter 26 that may be enclosed by a tipping paper, however,
depending
upon the smokable column material, a filter may be optional or omitted.
[0055] The smoking article shown in Figs. 1 and 2 can be a
cigarette, a
cigarillo, a little cigar, or the like. Alternatively, the article can a heat
but not burn
stick.
[0056] In still another aspect, the wrapping material can be
formulated as a
booklet of individual wrapping materials. The individual wrapping materials,
for
instance, can be adhered to each other using a smokable or edible adhesive.
The
book of wrapping materials can be used in roll-your-own applications where a
user
would use the wrapping material to make his or her own smoking article or heat
but not burn stick.
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[0057] In one aspect, the wrapping material of the present
disclosure can be
treated with a gum. In one aspect, the gum can serve as an adhesive. In one
embodiment, the gum may include alginates, arabic gum, guar gum, pectin,
polyvinyl alcohol, polyvinyl acetate, cellulose derivatives such as ethyl
cellulose,
methyl cellulose, and carboxymethyl cellulose, starch, starch derivatives, and
the
like.
[0058] In one particular embodiment, the gum may include an
Arabic gum,
cellulose, and/or cellulose derivatives. In one embodiment, cellulose
derivatives
include carboxy methyl cellulose (CMC), methylcellulose (CM), hydroxypropyl
methyl cellulose (HPMC).
[0059] Regardless of the gum used, the gum may be present on
the wrapping
material or web in an amount of from about 0.1% to about 15% by weight, such
as
from about 2% to about 5% by weight. In one embodiment, the gum may be
applied using direct or indirect coating methods. The gum can be applied via a
spray, such as a microspray, or may be otherwise applied so as to form a thin
coating over the desired area using, for instance, gravure printing.
[0060] In one embodiment, smoking articles made according to
the present
disclosure can also have reduced ignition propensity characteristics. For
instance,
the wrapping material of the present disclosure may be used as an outer
wrapper
of the smoking article and can have inherent reduced ignition properties or
can
optionally include a plurality of discrete reduced ignition areas spaced in
the axial
direction of the smoking article. For instance, in one embodiment, the
discrete
reduced ignition areas may be in the form of circular bands. The bands can
have
a width so that oxygen is limited to the burning coal for a sufficient length
or period
of time to extinguish the coal if the smoking article were left in a static
burn
condition. The bands, for instance, can have a width of generally greater than
about 3 mm, such as greater than about 4 mm, such as greater than about 5 mm,
and generally less than about 10 mm, such as less than about 8 mm, such as
less
than about 7 mm.
[0061] The spacing between the reduced ignition areas can
also vary
depending upon a number of variables. The spacing should not be so great that
the cigarette burns for a sufficient length of time to ignite a substrate
before the
coal burns into a reduced ignition area. The spacing also affects the thermal
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inertia of the burning coal, or the ability of the coal to burn through the
reduced
ignition areas without self-extinguishing. In general, the band spacing should
be
greater than about 5 mm, such as greater than about 10 mm, such as greater
than
about 15 mm, and generally less than about 50 mm, such as less than about 40
mm, such as less than about 30 mm. Each smoking article can contain from about
1 to about 3 bands.
[0062] In general, any suitable ignition reducing composition
can be applied to
the outer wrapper/wrapping material of the smoking article. In one embodiment,
for instance, the ignition reducing composition contains a film-forming
material.
For example, film-forming materials that can be used in accordance with the
present invention include alginates, guar gum, pectin, polyvinyl alcohol,
polyvinyl
acetate, cellulose derivatives such as ethyl cellulose, methyl cellulose, and
carboxymethyl cellulose, starch, starch derivatives, and the like.
[0063] In one particular embodiment, the film-forming
material may comprise an
alginate, alone or in combination with starch. In general, an alginate is a
derivative
of an acidic polysaccaride or gum which occurs as the insoluble mixed calcium,
sodium, potassium and magnesium salt in the Phaeophyceae brown seaweeds.
Generally speaking, these derivatives are calcium, sodium, potassium, and/or
magnesium salts of high molecular weight polysaccarides composed of varying
proportions of D-mannuronic acid and L-guluronic acid. Exemplary salts or
derivatives of alginic acid include ammonium alginate, potassium alginate,
sodium
alginate, propylene glycol alginate, and/or mixtures thereof.
[0064] In one embodiment, a relatively low molecular weight
alginate may be
used. For example, the alginates may have a viscosity of less than about 500
cP
when contained in a 3% by weight aqueous solution at 25 C. More particularly,
the alginates may have a viscosity of less than 250 cP at the above
conditions,
particularly less than 100 cP, and in one embodiment at a viscosity of about
20-60
cP. As used herein, viscosity is determined by a Brookfield LVF Viscometer
with a
suitable spindle according to the viscosity. At the above lower viscosity
levels,
alginate compositions can be formed at a higher solids content, but yet at a
low
enough solution viscosity to permit the application of the composition to a
paper
wrapper using conventional techniques. For example, the solids content of an
alginate solution made in accordance with the present invention can be greater
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than about 6%, particularly greater than about 10%, and more particularly from
about 10% to about 20% by weight.
[0065] At the above solids levels, alginate compositions used
in accordance
with the present invention can have a solution viscosity of greater than about
250
cP, particularly greater than about 500 cP, more particularly greater than
about
800 cP, and in one embodiment at a viscosity of greater than about 1,000 cP at
25 C. In general, the solution viscosity of the alginate film-forming
composition
can be adjusted depending upon the manner in which the composition is being
applied to the wrapper. For instance, the solution viscosity of the
composition can
be adjusted depending upon whether or not the composition is being sprayed
onto
the paper or printed onto the paper.
[0066] In other embodiments, it should also be understood
that depending upon
the application a relatively high molecular weight alginate may be used. For
example, the alginate may have a viscosity of greater than about 500cP when
contained in a 3% by weight aqueous solution at 25 C.
[0067] In addition to the film-forming material, the reduced
ignition composition
applied to the wrapper can contain various other ingredients.
[0068] For instance, in one embodiment, a filler can be
contained within the
composition. The filler can be, for instance, calcium carbonate, calcium
chloride,
calcium lactate, calcium gluconate, and the like. In addition to calcium
compounds, other various particles may be used including magnesium compounds
such as magnesium oxide, clay particles, and the like.
[0069] The ignition reducing composition, in one embodiment,
can be water
based. In particular, the ignition reducing composition may comprise an
aqueous
dispersion or aqueous solution. Alternatively, the ignition reducing
composition
prior to being applied to the paper wrapper may comprise a non-aqueous
solution
or dispersion. In this embodiment, for instance, an alcohol may be present for
applying the composition to the wrapper.
[0070] As opposed to a film-forming composition, the ignition
reducing
composition may also comprise a cellulose slurry (a type of dispersion). As
used
herein, a slurry containing papermaking materials is not a film-forming
composition. The cellulose slurry applied to the paper substrate may comprise
fibrous cellulose, one or more fillers, and/or cellulose particles. As used
herein,
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cellulose fibers and cellulose particles are to be differentiated from
derivatized
cellulose such as carboxymethyl cellulose. Cellulose fibers and cellulose
particles,
for instance, are not water soluble. In one embodiment, the cellulose slurry
applied to the paper substrate may comprise microcrystalline cellulose.
[0071] Once the ignition reducing composition is formulated,
the composition
can be applied to a paper wrapper in discrete areas. The manner in which the
composition is applied to the paper wrapper can vary. For example, the
composition can be sprayed, brushed, applied with a moving orifice, or printed
onto the wrapper. To form a treated area, the composition can be applied in a
single pass or in a multiple pass operation. For instance, the composition can
be
applied to the wrapping paper in successive steps in order to form areas on
the
paper having reduced ignition proclivity. In general, during a multiple pass
process, the treated areas can be formed by applying the composition during
from
about 2 to about 8 passes.
[0072] The amount of reduced ignition composition applied to
the wrapper can
also vary. For instance, the composition can be applied to the wrapper in an
amount less than about 15% by weight, such as less than about 10% by weight,
such as less than about 8% by weight. In general, the composition is applied
in an
amount greater than 1% by weight based upon the weight of the composition
within the reduced ignition areas.
[0073] As used herein, the above weight percentages are based
on the area
treated with the chemical components. In other words, the weight percentages
above for the reduced ignition composition is the amount applied within the
treated
areas as opposed to the total amount applied over the entire surface of the
wrapper.
[0074] Through the process of the present disclosure, reduced
ignition areas
can be produced having a relatively high permeability while also having a
relatively
low diffusivity. For instance, the reduced ignition areas can have a
permeability
greater than 10 CORESTA while still being capable of producing smoking
articles
that pass ASTM Test E2187-09 at least 75% of the time.
[0075] In general, the reduced ignition areas or the natural
wrapper itself can
have a diffusivity that is relatively low. The diffusivity can be measured at
room
temperature (23 C). In general, the diffusivity at 23 C of the reduced
ignition areas
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or the diffusivity of the inherent wrapper (without being coated or treated)
can be
less than about 0.5 cm/s, such as less than 0.4 cm/s, such as less than 0.3
cm/s,
such as less than 0.1 cm/s, such as less than 0.08 cm/s. In one embodiment,
the
reduced ignition areas may have a diffusivity of greater than about 0.01 cm/s,
such
as greater than about 0.03 cm/s, such as greater than 0.05 cm/s, such as
greater
than 0.1 cm/s, while still having the desired reduced ignition proclivity
characteristics. Diffusivity is measured using a Sodim CO2 diffusivity tester.
[0076] VVhile additives may not be necessary in the wrapping
material, as the
wrapping material according to the present disclosure naturally has good
manufacturing properties (e.g tensile strength) and sensory properties,
generally,
a wrapping material according to the present disclosure may include one or
more
additives. Additives may be used for manufacturing wrapping papers so as to
develop or give the wrapping material new properties, for instance chemical,
optical, sensory or mechanical properties such as tear strength or folding
resistance. In one embodiment, an additive may be a humectant, burn control
additives, wet strength agent, an oil-barrier and fat-barrier agent, a
antiblocking
agent, a dry strength agent, a softener, a flavoring agent, a wetting agent or
lattices.
[0077] In one embodiment, the web material can further
contain a humectant.
The humectant can be incorporated into the wrapping material for various
different
reasons in order to provide different benefits and advantages. For instance,
in one
embodiment, a humectant may be incorporated into the wrapping material in
order
to improve the processability and handling of the resulting fiber substrate.
[0078] VVhile various humectants may be incorporated into the
wrapping
material of the present disclosure, humectants may include a polyol, a non-
polyol
or a mixture thereof. Typically, a polyol generating agent may be sorbitol,
glycerol,
propylene glycol, triethylene glycol or a mixture thereof. Typically, a non-
polyol
generating agent may be lactic acid, glyceryl diacetate, glyceryl triacetate,
triethyl
citrate or isopropyl myristate or a mixture thereof. In one embodiment, the
humectant is glycerol, propylene glycol, or a mixture of glycerol and
propylene
glycol, glycerol being preferred glycerol, propylene glycol, or mixtures
thereof.
Regardless of the humectant selected, the humectant may be present in the
wrapping material in an amount of from 0.1% to about 30% by weight of the
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wrapping material, such as from about 1% to about 10%, such as from about 2%
to about 8% by weight of the wrapping material, or any ranges therebetween.
[0079] The burn control agent, for instance, may comprise a
salt of a carboxylic
acid. For example, the burn control agent may comprise an alkali metal salt of
a
carboxylic acid, an alkaline earth metal salt of a carboxylic acid, or
mixtures
thereof. Examples of burn control agents that may be used include a salt of
acetic
acid, citric acid, malic acid, lactic acid, tartaric acid, carbonic acid,
formic acid,
propionic acid, glycolic acid, fumaric acid, oxalic acid, malonic acid,
succinic acid,
nitric acid, phosphoric acid, or mixtures thereof. Particular burn controlling
agents
that may be used include potassium citrate, sodium citrate, potassium
succinate,
sodium succinate, or mixtures thereof. When present, the burn control agent
can
be applied to the wrapping material generally in an amount greater than about
0.1% by weight, such as in an amount greater than about 0.5% by weight, such
as
in an amount greater than about 1% by weight and generally less than about 5%
by weight, such as less than about 4% by weight, such as less than about 3% by
weight, such as less than about 2% by weight.
[0080] The finished web or wrapper is dried and wound into
rolls. For instance,
in one embodiment, the dried sheet is wound into bobbins having a width of
from
about 15 mm to about 80 mm, such as from about 19 mm to about 28 mm. Prior
to winding the web into a bobbin, the web may be calendered to increase the
smoothness and runnability of the material. In one embodiment, for instance, a
multi-nip calender device may be used.
[0081] These and other modifications and variations to the
present invention
may be practiced by those of ordinary skill in the art, without departing from
the
spirit and scope of the present invention, which is more particularly set
forth in the
appended claims. In addition, it should be understood that aspects of the
various
embodiments may be interchanged both in whole or in part. Furthermore, those
of
ordinary skill in the art will appreciate that the foregoing description is by
way of
example only, and is not intended to limit the invention so further described
in such
appended claims.
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