Note: Descriptions are shown in the official language in which they were submitted.
CA 02574826 2009-01-27
MODIFIED RECONSTITUTED TOBACCO SHEET
COMPRISING A BINDER AND WOOD PULP
BACKGROUND OF THE INVENTION
The present invention relates to a process for making a reconstituted tobacco
sheet
and more particularly to a process for making a reconstituted tobacco sheet
including a
flavoring compound contained in a gel matrix within the reconstituted tobacco
sheet and
even more particularly to a paper process for making a reconstituted tobacco
sheet
including an alginate based compound.
In the manufacturing of smoking articles and particularly cigarettes, it is
common
to use in the tobacco blend a percentage of strips of reconstituted tobacco.
The
reconstituted tobacco is generally prepared from tobacco fines, veins, stems
and other
waste tobacco products which are further processed and formed into sheets, cut
into strips
and blended in with fresh cut tobacco. The amount of reconstituted tobacco
used in a
tobacco blend for a smoking article varies, but is generally less than 20%.
Usually,
reconstituted tobacco sheets made via the paper process are absent of
additional binders,
such as alginate, guar, xanthan, acacia, pectin, other gums, and modified
cellulose
compounds.
Additionally, there has been great concern for the reduction of the ignition
propensity of smoking articles as there have been a substantial number of
fires which have
been attributed to burning cigarettes coming into contact with combustible or
flammable
materials. Therefore, there is a considerable effort being expended in the
industry to
provide smoking articles which provide a low ignition propensity smoking
article. Many of
these proposals include a modification of the wrapper for the smoking article.
Particularly,
coatings or additives have been made to wrappers for the smoking articles to
reduce the
porosity or to change the chemical properties of the wrapper.
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CA 02574826 2009-01-27
SUMMARY OF THE INVENTION
The present invention provides a novel process for making a reconstituted
tobacco
sheet.
The present invention also provides a smoking article, including a novel
reconstituted tobacco sheet in one layer of a wrapper for the smoking article.
The present invention provides a novel process for forming a reconstituted
tobacco
sheet having an alginate based coating.
The present invention provides a smoking article, including a novel
reconstituted
tobacco sheet having an alginate based coating in one layer of a wrapper for
the smoking
article.
Accordingly, the present invention provides a process for making a
reconstituted
tobacco sheet having a binder, comprising the steps of: preparing a slurry
containing a
mixture of up to about 80% by weight tobacco, and up to about 30% by weight of
said
binder; and coating a preformed reconstituted tobacco sheet, wherein said
sheet contains up
to about 80% wood pulp, with said slurry.
The present invention also provides a process for making a reconstituted
tobacco
sheet comprising the steps of: preparing a slurry including a binder, a
humectant, tobacco,
and a flavoring, said tobacco being up to about 80% by weight and dispersed in
an aqueous
solvent into said slurry, said binder being up to about 30% by weight and
dispersed
secondly into said slurry, said humectant being up to about 30% by weight and
dispersed
thirdly into said slurry, and then up to about 30% by weight of flavor being
dispersed lastly
into said slurry; coating a preformed reconstituted tobacco sheet with said
slurry; cutting
said sheet of reconstituted tobacco into longitudinal strips; and inserting a
plurality of said
longitudinal strips of said reconstituted tobacco into a cigarette adjacent a
column of
tobacco.
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The present invention also provides a process for making a modified
reconstituted
tobacco sheet, comprising the steps of: preparing a slurry containing tobacco
particles and
an aqueous solvent; extracting said slurry at about 160 F for about 30
minutes; separating
said slurry into an extract with water soluble compounds and solid portion;
mixing said
solid portion with wood pulp, wherein said wood is up to about 80% by weight;
forming
said solid portion into a reconstituted tobacco sheet over a Fourdriner paper
machine wire;
centrifuging and concentrating said extract; adding a first binder to said
extract, wherein
said first binder is up to about 30% by weight; adding a humectant to said
extract, wherein
said humectant is up to about 30% by weight; applying said extract to said
reconstituted
tobacco sheet and drying; slitting said reconstituted tobacco sheet into
elongated strips; and
inserting a plurality of said elongated strips into a cigarette adjacent a
column of tobacco.
The process according to the present invention provides a reconstituted
tobacco
sheet which includes up to about 80% by weight of tobacco; up to about 80% by
weight of
wood pulp, preferably up to about 60% by weight of wood pulp; up to about 30%
by
weight of a binder (e.g., alginate, guar, xanthan, acacia, pectin, other gums,
and modified
cellulose compounds), preferably up to about 20% by weight of a binder; and up
to about
30% by weight of flavoring compounds, preferably about 3% to about 5% by
weight of
flavoring compounds.
Processes for making a reconstituted tobacco sheet are known in the art. The
present invention provides a process for making a reconstituted tobacco sheet
having a
binder applied to the sheet to decrease sheet porosity, thereby lowering
ignition propensity
and cigarette burn rate. The binder may be alginate, guar, xanthum, acacia,
pectin, other
gums, and modified cellulose compounds. The resulting tobacco sheet with the
applied
binder is cut into lengths of preselected widths for use in a smoking article.
In one
embodiment, the strips are positioned longitudinally of the tobacco rod
between the
tobacco rod and an outer cigarette or smoking article wrapper.
. . _ . . j . . . . .
CA 02574826 2009-01-27
In a further aspect, the present invention provides a cigarette comprising: a
tobacco
column surrounded by an outer wrap paper; and, a partial inner wrap material
extending
longitudinally of said tobacco column and disposed between said outer wrap,
said partial
inner wrap being one or more strips of a reconstituted tobacco sheet which is
comprised of
up to about 80% by weight of wood pulp, up to about 30% by weight of a binder,
and up to
about 80% by weight of tobacco, said partial inner wrap being coated with a
coating
comprising up to about 80% by weight tobacco and up to about 30% by weight of
a binder.
Additional features and advantages of the present invention will become
apparent
to those skilled in the art upon consideration of the following detailed
description including
examples of the preparation of the reconstituted tobacco sheet of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The aspects and advantages of the present invention will be better understood
when
the detailed description of the preferred embodiments is taken in conjunction
with the
accompanying drawings, in which:
Figure 1 is a perspective view of a partial cigarette of the present invention
using
the reconstituted tobacco sheet of the instant invention;
Figure 2 is a perspective view of an unrolled cigarette wrapper including the
reconstituted tobacco sheet of the instant invention;
Figure 3 is an end view of the cigarette of Fig. 1;
Figure 4 is a perspective view of the cigarette paper of an alternative
embodiment
of the instant invention including the reconstituted tobacco sheet;
Figure 5 is a perspective view of the cigarette paper of an alternative
embodiment
of the instant invention including the reconstituted tobacco sheet;
Figure 6 is an end view of Fig. 5; and,
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Figure 7 is a partial cut away view of a cigarette with the cigarette paper of
an alternative
embodiment of the instant invention including the reconstituted tobacco sheet.
Figure 8 is a flow chart showing the modified paper reconstituted process for
making split
inner wrap.
DETAILED DESCRIPTION OF THE PREFERRED EMBDIMENTS
A cigarette with bum rate modification is shown in Figure 1 and may be
described as a
partial double wrap cigarette 10. As seen therein, the partial double wrap
cigarette 10 of the
present invention incorporates a standard column of tobacco 13 which extends
from an exposed
end to the filter 15. Circumscribing the tobacco colurrm 13 is the outer wrap
of the cigarette
paper 12. Interior of the outer wrap cigarette paper 12 is a separate partial
inner wrap layer or
strip 14a and 14b. The separate partial inner wrap layer 14a and 14b acts as a
burn rate modifier
for the tobacco column 13 by altering the burn characteristics of the
cigarette 10. As can be seen
from the embodiment shown in Figure 1, the inner wrap layer strips may be co-
axial to the
tobacco column 13 and may extend substantially the length of the tobacco
column from the
exposed end to the filter 15. By insertion of the separate partial inner wrap
layer 14a and 14b
which in this embodiment extends co-axial to the tobacco column 13,
modification may be made
to the bum rate of the cigarette in such a manner that the burn rate may be
adjusted depending
upon the packing density of the tobacco, porosity of the outer wrap paper 12
and additives to the
outer wrap, width of the separate partial inner wrap layer 14a and 14b,
porosity of the inner wrap
layers 14a and 14b, and additives to the inner wrap strips. Alternatively, the
inner wrap layer may
be shortened to not extend the full length of the tobacco column 13 or may
extend in varying
directions. Thus, many alterations to the bum rate of the partial double wrap
cigarette 10 of the
present invention may be established based upon the combination of factors
noted herein, among
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others.
As depicted in Figure 1, the partial double wrap cigarette 10 of the present
invention
which has a modified bum rate characteristic incorporates an outer wrap paper
12 with a first and
a second separate partial inner wrap strip 14a and 14b. The outer wrap
cigarette paper 12 maybe
a normal porosity paper which typically exhibits a porosity of 15-80 CORESTA
units. In
combination with the outer wrap cigarette paper 12 is positioned at least one
partial inner wrap
layer which can modify the bum rate characteristics of the cigarette 10. As
shown, a first and a
second partial inner wrap layer 14a and 14b are provided on opposite sides of
the tobacco column
13. In order to provide substantially equivalent burn rate characteristics
along the entirety of the
tobacco column 13, the partial inner wrap strips 14a and 14b may substantially
extend and be co-
axial with the tobacco column 13 to the filter 15.
As depicted in the embodiment of Figure 4, the partial inner wrap layers 14a
and 14b
extend from end to end of the tobacco column 13 and may be positioned such
that they are either
equal distant from each other or may be placed in alternative positions based
upon the desired
burn rate characteristics.
Turning to Figure 3, it is apparent that the partial double wrap cigarette 10
of the present
invention has alternating high diffusion areas 21 and low diffusion areas 22
based upon the
placement of the inner wrap layers or strips 14a and 14b. As can be seen, the
high diffusion areas
21 of which there is at least one, allow for increased permeation of CO and
oxygen gases through
the barrier formed by the outer wrap 12 while maintaining normal deliveries.
In combination, low
diffusion areas 22 which are defined by the circumferential extent of each of
the partial inner wrap
layers 14a and 14b may potentially block a significant portion or all of the
inflow and outflow of
gases therethrough related directly to the porosity of the inner wrap layer
14a and 14b in
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combination with the outer wrap layer 12. The co-linear zones of high
diffusion area 21 and low
diffusion area 22 may exhibit a porosity of greater than 14 CORESTA for the co-
linear high
diffusion areas and less than 8 CORESTA for the co-linear low diffusion areas.
As shown in the drawings, the construction of the cigarette with burn rate
modification is a
partial double wrap cigarette 10 depicted herein and utilizes a standard outer
wrap cigarette paper
12 which, in a typical cigarette, is 27mm wide. Placed along the interior of
the outer wrap, as
shown in Figure 2 and in Figure 4 in an alternative embodiment, is located the
separate partial
inner wrap layer 14a and 14b which may substantially extend along the length
of the outer wrap
12. While the outer wrap of the cigarette paper may be standard porosity and
construction, the
partial inner wrap of this embodiment has a first and a second strip 14a and
14b each of which
may be 4mxn in width and which may have a porosity of less than 8 CORESTA
units. Therefore,
combined, the two inner wrap layers or strips 14a and 14b may circumscribe
about Smm of the
circumference of the partial double wrap cigarette 10 of the present invention
but may extend
around a circumference of up to 15 mm of the tobacco coluuenn in relation to a
standard cigarette
- dimension. Any combination of the partial inner wrap and outer wrap may work
depending on the
variables noted, such as porosity of each paper, but it is felt that good burn
rate characteristics as
well as limited effects to smoke characteristics and flavor may be achieved by
incorporating an
inner wrap which covers less than about 75% or preferably less than about 60%
and even more
preferably less than about 35% of the circumference of the outer wrap. This is
a function of the
overall cigarette and may vary depending on the circumference of the outer
wrap. However,
variations are available to achieve the same favorable results utilizing the
inventive aspects of the
present design and such descriptions are not felt to be limiting and are
exemplary only.
Alternatively, many different constructions may be utilized to provide the
cigarette with
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burn rate modification as set forth herein. As may be understood, a single
inner wrap layer or a
plurality of inner wrap layers ma.y be provided based upon the desired
characteristics and burn rate
modification. Thus, as previously mentioned, combinations of low porosity
inner wrap segments
and higher porosity outer wrap segments may be utilized to provide various
linear burn rates
which may be desirable. Thus, a typical linear burn rate of 6.0mm per minute
may be reduced as
desired based upon a combination of porosity of outer wrap and partial inner
wrap strips among
other factors and may readily be reduced to below 4 mm/minute if needed. This
includes
formulation of single inner wrap strips of lower porosity or replacement of
the inner wrap strips
with various construction material including reconstituted tobacco, low
porosity paper,
reconstituted tobacco, a polymer based material, other paper or material. The
inner wrap strips
are coated with binders, such as alginates (e.g., sodium alginate), guar,
xanthum, acacia, pectin,
other gums, modified cellulose compounds or hydrocolloid-based compounds,
which act as burn
modifiers or inhibitors and which create at least one low diffusion area along
the tobacco column.
The binders decrease the porosity of the coated reconstituted tobacco sheet,
which are used as
inner strips, and provide adequate characteristics such that the entire
combination of outer wrap
porosity, tobacco packing density, inner strip burning characteristics, inner
strip porosity, and
other factors cause the cigarette to exhibit a desired burn rate.
As shown in Figures 4-7, various embodiments may be utilized in order to
create the low
porosity zone. As depicted in Figure 4, the opened standard outer wrap 12 is
lined with a
plurality of inner wrap or inner layer strips 16a, 16b, 16c and 16d. These
strips may be placed
equidistantly apart along the interior of the outer wrap 12 and positioned
away fromthe edges or
seam where the outer wrap is adhered to itself during rolling within the
garniture of the cigarette
maker. As depicted, the strips 16a-16d may all be fed into the garniture and
incorporated on the
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interior of the outer wrap adjacent the tobacco column. Placement of the
partial inner wrap strips
coated with an alginate based compound modifies the bum rate to a desired
level such that the
rate may be decreased sufficiently to cause either a significantly reduced
static bum rate or self-
extinguishment at a desired interval.
As shown in Figure 5, an inner layer with non-linear sides 17 as compared to
the edges of
the outer wrap 12 may be utilized as the partial inner wrap in order to create
the low porosity
zone. As shown therein, the inner wrap layer 17 may have be a wave form so
that the placement
of the low porosity zone changes in position along the tobacco column axis.
Such non-linear
placement of the low porosity zone may allow for different positioning of the
cigarette during
static burn and insure that the desired static burn rate takes effect
regardless of the position of the
cigarette.
Depicted in Figure 6 is another embodiment of the cigarette with burn rate
modification of
the present invention. As seen therein, a high diffusion area 21 and low
diffusion area 22 is
defined by addition of a partial double wrap inner wrap layer 18 which
circumscribes a portion of
the tobacco column 13 on the interior of outer wrap 12. The partial inner wrap
layer 18, as
depicted in the Figure 6, extends approximately half way around the perimeter
of the tobacco
column 13. However, many different configurations may be utilized in order to
achieve the
appropriate linear burn rate through the burn rate modification set forth. The
partial double wrap
inner wrap layer 18 may be comprised of standard cigarette paper which has a
low porosity of less
than 7 CORESTA units or cigarette paper coated with bum rate modifiers, or may
be alternative
construction such as a reconstituted tobacco sheet with or without additives
and which typically
has a low CORLSTA unit value, typically less than 5 and more preferably less
than 3. A
secondary benefit of utilizing reconstituted or reconstituted tobacco sheets
as the partial double
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wrap inner wrap layer 18 is that the coloring of the inner wrap may be such
that it is similar to the
tobacco column 13 and does not provide a contrasting whitened area which
extends along the low
diffusion area 22. Additionally, a polymer film or other material may be used
as the partial double
wrap inner wrap layer 18. It may be preferable for the partial double wrap
inner layer displayed in
Figure 6 to be 2-14 mm in width or alternatively, less than 75% of the
circumference of the outer
wrap in order to obtain the appropriate burn rate modification desired wherein
the linear bum rate
is sustained at a low enough level, preferably below 4.0 mm per minute.
As depicted in Figure 7, an alternative embodiment is disclosed wherein a
plurality of inner
wrap strips 19 are utilized substantially surrounding the tobacco column 13 on
the interior of the
outer wrap 12. The plurality of inner wrap strips 19 may be fed into the
garniture adjacent the
outer wrap 12 and encircling the tobacco column 13 as it is formed within the
cigarette maker.
The plurality of strips 19 may be comprised of a low porosity cigarette paper
individually fed into
the cigarette maker or by a single or multiple strips fed into the cigarette
maker adjacent to the
garniture and cut to the appropriate strip widths. As depicted in Figure 7, a
plurality of inner
wrap strips 19 are utilized and extend co-axially substantially along the
length of the tobacco
column 13. Preferably, the plurality of strips 19 extends along the entire
tobacco column length
such as to modify the burn rate along the entire tobacco column regardless of
cigarette
positioning. It is felt that by providing a plurality of strips 19 as depicted
in Figure 7, a more even
modification of the burn rate of the cigarette may be produced.
As may be appreciated, extending the inner wrap layer substantially along the
length ofthe
tobacco column 13 such that they are co-axial provides a significant benefit
over alternating rings
which are perpendicular to the axis of the tobacco column 13. Such
perpendicular rings which
alternate along the length of the tobacco column may provide a non-linear burn
rate of the
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tobacco column 13. Thus, in such a design where there are circumscribing rings
around the
tobacco column, the linear burn rate becomes variable between a low linear bum
rate to a high
linear burn rate depending upon the porosity of the paper at the point of the
rings as opposed to
the porosity of the non-adjusted paper between the rings. Such non-linear burn
rate may in fact be
undesirable in that continued free burning of the tobacco column between the
rings for significant
periods of time does not produce an appropriate burn rate modification which
can be depended
upon through the entire tobacco column length. Further, at points where the
low porosity rings
are present, a smoker may puff on the cigarette as the burning of the tobacco
colu.mn passes over
a low porosity ring. At such a point, it is thought that the deliveries of the
cigarette may be
altered significantly to increase the CO and other compounds provided as the
cigarette bums over
one of these rings. Thus, the partial double wrap inner layer of the present
invention overcomes
these problems by providing known standard deliveries over the entire length
of the tobacco
column while also modifying the burn rate along the entire co-axial length.
In the design of the cigarette with the burn rate modification 10 of the
present invention, it
may be desirable to incorporate the inner wrap layers, whether a plurality of
strips or a single
layer, away from the seam of the outer wrap 12. As is known in cigarette
manufacturing, the
seam 23, depicted in Figure 1, is formed by the maker by over-wrapping the
side edges 24 of the
outer wrap 12. In typical cigarette manufacturing, an adhesive is applied
along one of the edges
24 prior to folding of the outer wrap and formation of the tobacco column 13.
During
manufacturing of the cigarette with burn rate modification 10 of the present
invention, it is
desirable to maintain the partial inner wrap layer away from the seam portion
to assure that the
outer wrap 12 is properly formed and the partial inner wrap layer does not
intercede in the
formation of the tobacco column or adhesive of the outer wrap layer. Thus, as
depicted in the
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embodiments, the partial inner wrap layers are shown to be placed away from
the side edges 24 so
that the inner wrap portions will not interfere with the seam of the outer
wrap 12 nor interfere
with the forrna.tion of the tobacco column within the garniture in a typical
cigarette manufacturing
machine. Thus, the cigarette with burn rate modification of the present
invention may be
implemented on standard cigarette making machines with only minor
modifications made to the
paper feeding devices and no modifications therefore will necessarily be
required within the
garniture. It is also apparent that in any of the embodiments shown herein the
strips may be
alternatively placed on the exterior of the cigarette and retained on the
wrapper by adhesives or
other means so that there are still formed co-linear zones of high and low
porosity.
The cigarette with burn rate modification of the present invention may be
designed with
variations in outer wrap and inner wrap paper characteristics. As previously
explained, standard
outer wrap designs are such that the typical outer wrap has a linear laid out
width of 27mm and
generally a porosity of between 15 and 80 CORESTA units. As is generally
understood,
significantly decreasing the outer wrap porosity changes the deliveries and
linear burn rate of the
cigarette. Modification of the standard burn rate for a normal or typical
cigarette maybe obtained
through addition of a partial inner wrap to the cigarette. The partial inner
wrap may be a single
inner wrap portion or may be a plurality of inner wrap strips as shown in the
various figures. The
partial inner wrap may have paper characteristics with a significantly reduced
porosity such that
the inner wrap paper exhibits a porosity of less than 8 CORESTA units. If a
single inner wrap
strip is utilized, the inner wrap layer may have a width of between 2-15 mm.
The porosity of the
inner wrap layer may be adjusted from any where to 0 to 8 CORESTA units.
EXAMPLES
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A more comprehensive understanding of the invention can be obtained by
considering the
following examples. However, it should be understood that the examples are not
intended to be
unduly limitative of the invention.
Example 1
Several product examples were made using the construction of a partial strip
wrap or
partial inner wrap cigarette using the inventive techniques and construction
described herein. In
the exainples, a control cigarette was used having no partial inner wrap
strips which exhibited a
linear bum rate of between 4.3-4.7 mm/mi.n. Different materials were utilized,
as detailed in the
chart below, for the partial inner wrap strips ranging from standard treated
paper to band cast
tobacco material.
Examples of cigarettes with two band cast inner wrap strips having a porosity
of
band cast material less than 5 CORESTA units:
Outer Outer Inner Strip Linear Burn Self
Wrapper Wrap Extinguishment
Porosity Citrate Inner Width Rate (LBR) On 10 layers
Strips
Cig. CORESTA % Number mm mm/min %
1 50 0.5 0 0 4.3 0
2 50 0.5 2 4 3.1 100
3 50 0.5 2 5 2.6 100
4 50 0.5 2 6 2.7 100
5 40 0.7 0 0 4.7 0
6 40 0.7 2 3 3.8 48
7 30 0.6 0 0 4.3 0
8 30 0.6 2 4 3.1 100
Examples of cigarettes with two cigarette paper strips treated or covered with
sodium alginate having a porosity of inner strip paper less than 5 CORESTA
units:
Outer Wrapper Outer Inner Linear Burn Self
Wrap Strip Extinguishment
Porosity Citrate Inner Strips Width Rate (LBR) On 10 layers
Ci . CORESTA % Number mm mm/min %
9 70 0.6 0 0 4.4 0
10 70 0.6 2 2 3.8 25
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Examples of cigarettes detailing smoke deliveries of two samples with band
cast strips:
Outer Self
Outer Wrap Inner Linear Burn Extinguishmen
Wrapper Strip t
Porosity Citrate Inner Width Rate (LBR) On 10 layers tar Nico- CO Puff
Strip tine
Clg CORESTA % Number mm mm/min % mg/ mg/ mg/ Num-
ci ci ci ber
11 70 0.6 2 4 3.9 90 15.5 1.4 12.2 10.3
12 50 0.5 2 4 3.8 90 14.5 0.9 14.6 7.3
In the exainples presented, it is apparent that the addition of the partial
inner wrap to the
cigarette had a definite impact on linear burn rate and self extinguishment as
compared to the
control cigarette. The linear burn rate for the cigarettes using the present
invention was directly
affected and evidenced a reduction in linear burn rate by up to 40 percent.
Where inner wrap
strips were utilized having a width of at least 4 mm, all test sainples self
extinguished. Narrower
width strips had differing results which could be modified by using
alternative additives or
increasing the number of strips. References to the self-extinguishment of the
cigarette on 10
layers are related to the NIST test for cigarette ignition propensity.
Smoking Article Including Strips of Reconstituted Tobacco
The separate partial inner wrap strips 14 may be strips of reconstituted
tobacco made in
accordance with the specific formula and process for making same as discussed
hereinafter. The
outer wrap cigarette paper 12 may be a normal porosity paper which typically
exhibits a porosity
of 15-80 CORBSTA units. As shown, two strips 14 of a reconstituted tobacco
sheet are provided
on opposite sides of the tobacco column 13 to provide a partial inner wrap
layer. The partial i.nner
wrap layer including the reconstituted tobacco strips 14 may extend
substantially the length of and
be co-axial with the tobacco column 13. In one embodiment, the strips are
placed equidistant
from each other such that the resulting cigarette burns evenly.
PrMaration of a Reconstituted Tobacco Sheet Having Binder
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Figure 8 is a flowchart illustrating the modified reconstituted tobacco
process for making
split inner wraps. In the preparation of a reconstituted tobacco sheet for use
in a cigarette,
tobacco particles, such as tobacco fines, stems, scraps, cut laniina, shredded
stems, or
combinations thereof are slurried in an aqueous solvent, such as water,
wherein the ratio is one
part tobacco to 11-20 parts aqueous solvent. The solution is extracted at
about 160 F for about
30 minutes. The solution is then separated into an extract with water soluble
compounds and
solid/fibrous portion via separation techniques known in the art, such as
centrifugation or
filtration. The solid/fibrous portion is refined and mixed with over 10% wood
pulp, made from
wood fibers that have been refined to a pulp, and an optional second binder,
such as alginate (e.g.,
sodium alginate), guar, xanthum, acacia, pectin, other gums, modified
cellulose compounds, and
hydrocolloid based compounds. This mixture of solid/fibrous tobacco, wood
pulp, and optional
second binder is then made into a reconstituted tobacco sheet via a paper
process known in the
art.
The extract, meanwhile, can optionally be treated with particular adsorbents
to selectively
remove undesired constituents. The extract is then centrifuged and the
adsorbent now containing
the constituents is discarded. The extract is then concentrated. A first
binder, such as alginate
(e.g. sodium alginate), guar, xanthum, acacia, pectin, other gums, modified
cellulose compounds,
and hydrocolloid-based compounds is added to the extract. Also, a humectant,
such as glycerin,
can be added for sheet pliability and is generally added before the binder and
before any additional
flavorant. A desired flavoring can also be added to the extract.
The new extract mixture is then reapplied to the preformed reconstituted
tobacco sheet.
Optionally, a third binder mix solution, such as alginate (e.g., sodium
alginate), guar, xanthum,
acacia, pectin, other gums, modified cellulose compounds, and hydrocolloid-
based compounds,
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can be size pressed and/or sprayed onto the reconstituted tobacco sheet. The
reconstituted
tobacco sheet can then be dried and slit into elongated strips of a desired
width and wound onto a
bobbin. The elongated strips can be used as longitudinally extending strips
along the outer
periphery of a tobacco rod and the inner surface of an outer paper wrap.
In a preferred mix, the tobacco is up to about 80% by weight; the wood pulp is
up to
about 80% by weight, preferably up to about 60% by weight; the binder is up to
about 30% by
weight, preferably up to about 20% by weight; and, if a flavoring is added,
the flavoring will be up
to about 30% by weight, preferably from about 3% to about 5% by weight.
The following examples demonstrate the procedure that was followed in
preparing the
reconstituted tobacco sheet having a binder for use in a smoking article.
Example 2
In the process of making a reconstituted tobacco sheet, 500 pounds of a
combination of-
tobacco and wood pulp (1:3 to 3:1 ratio) was extracted with 750 gallons of
water in a mixing
vessel, at 140 C to 190 C for 30 to 45 minutes. Following extraction, the
mixture was separated
into solids (fiber) and liquid (extract) streams via centrifugation,
filtration, or pressing.
The liquid extract was concentrated by vacuum evaporation and mixed thoroughly
with 60
pounds of glycerin. In a separate vessel, an alginate solution was prepared by
thoroughly
dispersing 40 pounds of sodium alginate in 135 gallons ofwater. The
concentrated extract with
glycerin was then thoroughly mixed with the alginate solution. Optionally, the
liquid extract was
gently agitated for 20 to 45 minutes with 75 pounds of a powdered solid
adsorbent, such as
bentonite (diatomaceous earth), carbon, cyclodextrin, cellulose acetate, or
combinations thereof,
to selectively remove nitrogen and other undesired components. After
agitation, the adsorbent
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WO 2006/014995 PCT/US2005/026557
was separated and discarded from the extract via centrifugation. The extract
was then
concentrated and treated with glycerin and alginate as described above.
Meanwhile, the solid stream was put through a refiner to fibrillate the fibers
into a
tobacco-wood pulp. The pulp was then used to make base sheets over a
Fourdriner paper
machine wire and dried. Any of the two concentrated extracts as prepared above
were then added
back to the base sheets either via size pressing or spraying. The finished
sheet was finally dried
and slit into strips and wound onto bobbins to be used as split inner wraps.
Example 3
Sheets were prepared and slit as described in Example 2, except that the
alginate solution
was added directly to the base sheet, instead of being mixed with the
concentrated extract. Also,
25 pounds of precipitated chalk or chitosan (inorganic or organic inert
fillers) were added to the
refined pulp mixture before making base sheet over the Fourdriner machine
wire. Other inert
fillers include liposan and combinations of chalk, chitosan, and liposan.
It is to be understood that the invention is not to be limited to the specific
examples
shown, because the parameters set forth in the examples may be varied by
appropriate changes of
the amounts of the constituents within the reconstituted tobacco sheet mix
used in the examples.
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