Note: Descriptions are shown in the official language in which they were submitted.
~ 157732
NOVEL TOBACCO STEM MATERIAL
The present invention is concerned with novel
shredded stem material.
This application is a division of copending
application Serial No. 372,861 filed March 12, 1981.
In the manufacture of cigarettes, tobacco leaf is
processed to separate the stems from the lamina. The
lamina are shredded and formed into cigarettes or other
smoking articles. The stems are not successfully
utilizable as such in cigarette making because of their
relatively large diameter, their hard nature and poor
burning properties.
Nevertheless, tobacco stem material constitutes a
substantial proportion of the leaf, usually about 20 to
25% of the weight thereof, and contains tar, nicotine
and other materials common to the lamina. In the past,
therefore, efforts have been made to process the stem
material for use in smoking articles but such
procedures have generally been unsatisfactory,
unsuccessful or inefficient.
One prior art procedure which has been adopted,
involves passing the stems, usually after moistening to
about 30 wt.% moisture, between rollers which act to
crush the stems into sheet material, and cutting the
sheet material into shreds for mixing with shredded
lamina from which the smoking article is made. The
product of this operation is commonly termed "cut
rolled stem" (CRS). Cut rolled stem suffers from the
drawbacks that it has only limited filling power, i.e.,
it has a limited ability to fill a cigarette tube, and
hence more material is required to be present in the
cigarette tube to achieve the same hardness of
cigarettte than for a higher filling power material.
A variation of this prior art procedure involves
3~ soaking and fast drying of the cut rolled stem, which
produces a product commonly known as "enhanced cut
rolled stem" which has an improved filling power as
compared with the cut rolled stem.
,,~,
1 157732
Another prior art procedure is described in U.S.
Patent No. 4,094,323 assigned to American Brands Inc.
wherein the stem material first is conditioned at a
temperature of 115 to 170C under a superatmospheric
pressure and thereafter is fiberized and expanded using
a pressurized shredder comprising closely-spaced
counter-rotating ribbed plates at an elevated
temperature of about 115 to 170C. This procedure
produces a fiberized and expanded stem material having
a substantially improved filling power when compared
with cut rolled and enhanced cut rolled stem.
However, this latter prior art procedure also
produces a considerable proportion of fine particulate
material or "dust", as determined by passage through an
18-mesh sieve, usually about 30 wt.~, which is less
suitable for use directly in cigarette making. The
particulate material may be separated from the
fiberized expanded stem prior to utilization of the
latter and may be used to form reconstituted tobacco
sheet, but such a procedure is not always available and
also means additional processing. The properties
ascribed to the fiberized stem material in U.S. Patent
No. 4,094,323 are determined after separation of the
fine particulate material.
In addition, while the fiberized and expanded stem
material have a substantially improved filling power,
when compared with CRS or enhanced CRS, other
properties of the product are less satisfactory from
the point of view of utility. The burn rate of the
material is substantially increased with respect to CRS
and enhanced CRS, meaning that, while a lesser combined
weight of shredded tobacco lamina and stem may be used
in the cigarette for the same overall hardness as a
blend of shredded tobacco lamina and CRS, nevertheless,
35 the increase in burning rate of the cigarette which
results from the lesser overall amount of tobacco and
the increased burning rate of the fiberized and
expanded stem material is detrimental.
1 157732
Furthermore, the pressure drop which results along
a cigarette made therefrom is substantially greater
than for a cigarette made from enhanced CRS which in
turn is greater than for a cigarette made from CRS,
under the same cigarette conditions. The pressure drop
along the cigarette relates to the ability of the
smoker to draw smoke from the cigarette into his mouth,
and lower values are generally considered more
satisfactory than higher values.
The problem to which the present invention is
directed is the production of a shredded stem material
having a decreased burn rate compared with CRS,
enhanced CRS and the fiberized enhanced stem and an
improved filling power when compared with CRS and
enhanced CRS while not significantly adversely
affecting the pressure drop characteristics when
compared with CRS, while at the same time avoiding the
production of large amounts of fine particulate matter
during the shredded stem formation.
In accordance with the present invention, there is
provided a novel shredded tobacco stem material which
in substantially fibrous form and which is
characterized by a burn rate which is at least about
20% less, preferably about 20 to about 50% less than
that of cut-rolled stem made from the same type of stem
material under the same cigarette burning conditions.
In general, the burn rate of the novel shredded stem
material is less than about 70 mg/min, preferably about
40 to about 60 mg/min.
The term "burn rate" as used herein with reference
to the product of the invention and other processed
stem material refers to the rate of burning of the
material when formed into a cigarette having a diameter
of 7.95 mm, a moisture level of 12.5 wt.% and a density
35 of 0.215 g/cc wrapped in non-porous phosphate cigarette
paper.
When formed into a cigarette, the novel stem
material also produces a carbon monoxide content in the
smoke of 0.47 to 1.14 mg per puff, as determined by
1 1S7732
Canadian Standard smoking procedures leaving a 30 mm
butt.
The novel shredded tobacco stem material also
usually exhibits specific pressure drop and filling
power characteristics when formed into a cigarette.
The novel shredded tobacco material usually exhibits a
pressure drop through the tobacco portion of the
cigarette of 2.5 to 3.5 cm of water at a flow rate of
17.5 ml/sec, a cigarette density of 0.215 g/cc and a
cigarette length of 85 mm. The filling power of such
stem material usually is 5.2 to 6.0 g/cc.
In accordance with a particularly preferred
embodiment of the invention, therefore, there is
provided shredded tobacco stem material in
substantially fibrous form characterized by: (a) a burn
rate of from about 40 to about 60 mg/min when formed
into a cigarette having a diameter of 7.95 mm, a
moisture level of 12.5 wt.%, and a density of 0.215
g/cc wrapped in a non-porous cigarette paper, (b) a
carbon monoxide content of smoke from burning a
cigarette formed therefrom of 0.47 to 1.14 mg per puff
of smoke, as determined by Canadian Standard smoking
procedures, (c) a pressure drop of 2.5 to 3.5 cm of
water at a flow rate of 17.5 ml/sec through a cigarette
formed therefrom having a tobacco length of 85 mm and a
density of 0.215 g/cc, and (d) a filling power of 5.2
to 6.0 g/cc.
The novel shredded stem material is formed by a
novel shredding me~hod which forms the subject of the
claims of the parent application. In accordance
therewith, a mass Gf tobacco stem, stalk or winnowings
is treated with water to uniformly distribute water
throughout the mass and to thoroughly soak the tobacco
stem, stalk or winnowings within the mass to provide an
overall moisture content of about 30 to about 60~ by
weight. The soaked stem, stalk or winnowings is
mechanically fiberized at atmospheric pressure between
closely-spaced counter-rotating fiberizing surfaces to
form shredded tobacco stem in substantially fibrous
1 157732
form. The shredded material is dried to any desired
moisture content.
As noted above, the novel shredded stem material
possesses a burn rate which is at least about 20%,
preferably 30 to about 50%, slower than that of CRS
made from the same type of stem material under the same
cigarette burning conditions. The burn rate also is at
least about 10% better than enhanced CRS.
The burn rate for cut rolled stem typically is
about 80 mg/min, for enhanced cut rolled stem is
typically about 75 mg/min, and for the fiberized
expanded stem of U.S. Patent 4,094,323 is typically
about 82 mg/min.
The significance of the lower burn rate is that a
lighted cigarette containing the product of the
invention, usually in a blend of from about 2 to about
50~ by weight thereof with shredded tobacco lamina,
burns slower than a cigarette containing the same
weight of a blend of any other of the prior art stem
materials with tobacco lamina. Accordingly, less
tobacco lamina needs to be used to get the same burn
rate as prior art blends, thereby realizing tobacco
economy and a lesser tar and nicotine content in the
tobacco smoke. Further, it has been found that the
lower burn rate also leads to a decrease in the
proportion of products of combustion, including tar,
nicotine and, as discussed in more detail below, carbon
monoxide. Hence, further decreases in tar and nicotine
content of the tobacco smoke from blends with tobacco
lamina can be achieved.
The shredded stem material of this invention when
made into a cigarette produces a carbon monoxide
content in the smoke which is significantly less per
puff of smoke than the carbon monoxide content of CRS
35 and enhanced CRS. Generally, the carbon monoxide
content in the smoke is at least about 20% less than
that of CRS.
It has been common practice to perforate cigarette
paper to dilute the carbon monoxide in the tobacco
1 157732
smoke with air drawn through the perforations and to
add flavour to the tobacco to compensate for that lost
as a result of dilution of the tobacco smoke.
In view of the lower carbon monoxide content of
the smoke produced by cigarettes containing the novel
shredded stem material of this invention, the necessity
for such manipulàtion may be decreased or even
eliminated.
The carbon monoxide content of the smoke which is
produced from a cigarette consisting of the novel
shredded stem material is 0.47 to 1.14 mg per puff of
smoke, when determined as described above. These
values compare with a typical value for CRS of about
2.5 mg per puff and for enhanced CRS of about 1.9 mg
per puff under the same burning conditions.
These beneficial results of decreased burn rate
and decreased carbon monoxide and other combustion
products content of smoke are exhibited by the novel
product of the invention while at the same time
increasing filling power when compared to CRS and
enhanced CRS and decreasing pressure drop when compared
with enhanced CRS and with the fiberized and expanded
stem material of U.S. Patent No. 4,094,323.
As mentioned previously, the filling power of a
cigarette filler material is important since it
determines the quantity of the material required to
achieve a given hardness of cigarette. The greater the
filling power the less filler material is required to
achieve the given hardness.
The novel shredded stem of this invention has a
better filling power than CRS and also enhanced CRS,
which itself is an improvement over CRS. The improved
filling power exhibited by the novel shredded stem
material, however, does not attain typical values for
35 the fiberized and expanded stem material of U.S. Patent
4,094,323. However, the filling power exhibited by the
latter product is attained at the considerable expense
of a significantly increased burn rate when compared
1 157732
with CRS and an increased pressure drop when compared
with CRS.
The improved filling power of the product of this
invention is accompanied by a significantly decreased
burn rate as compared with CRS and a decreased pressure
drop as compared with enhanced CRS. Accordingly, the
product of this invention may be used to decrease the
overall quantity of tobacco used in a cigarette to
achieve the same hardness while not increasing the burn
rate but rather decreasing it.
The filling power for the product of the invention
preferably is about 5.2 to about 6.0 cc/g, as compared
with typical values for CRS of 4.0 cc/g, for enhanced
CRS of 4.5 cc/g and for fiberized expanded stem (U.S.
Patent 4,094,323) of 6.6 cc/g. These filling power
results are for the whole of the shredded material. If
the particulate material is removed, the filling power
is increased by about 10%.
Pressure drop is another significant parameter of
the product of this invention. The pressure drop is
measured in cm of water at a tobacco industry standard
flow rate of 17.5 ml/sec for a cigarette as described
above. In view of the fact that a higher pressure drop
signifies that a smoker must pull harder on the
cigarette to draw smoke into his mouth and that a lower
pressure drop permits the filter size to be increased
so as to decrease the tar and nicotine content of the
cigarettes, lower pressure drop values are considered
to be better than higher pressure drop values.
The product of this invention exhibits a pressure
drop of less than that for enhanced CRS and for
fiberized expanded stem, which themselves tend to be
about the same. The pressure drop is greater than that
for CRS but not significantly adversely so, especially
35 when the pressure drop is considered in conjunction
with filling power, for which the product of this
invention is vastly superior to CRS.
The shredded tobacco stem material of this
invention, when in cigarette form, preferably exhibits
1 157732
a pressure drop of 2.5 to 3.5 cm of water at a flow
rate of 17.5 ml/sec, as compared with a typical value
of about 1.3 cm of water for CRS, and a typical value
of about 4.1 cm of water for both enhanced CRS and
fiberized expanded stem, under the same cigarette
conditions.
The novel shredded stem material in substantially
fibrous form, therefore, exhibits a combination of
parameters which are not shown by any other processed
stem material of which the applicants are aware and is
able to be used in a more flexible manner in blends
with shredded lamina.
The shredded stem material of this invention may
be formed by the method which is the subject of the
claims of the parent application and as also discussed
hereinafter for completeness. That method includes an
initial treatment of a mass of the tobacco stem
material with water, mechanically fiberizing the
treated material at atmospheric pressure, and
decreasing the moisture content to a desired level.
In this first step of the process, a mass of
tobacco stem material, which may first be cut into
convenient lengths, for example, about 0.5 to 6 inches,
is treated with water.
The water treatment is effected to uniformly
distribute water throughout the mass of stem material
and to thoroughly soak the tobacco stem material within
the mass to provide an overall moisture content of
about 30 to about 60% by weight, preferably about 50 to
about 60% by weight.
The procedure involves soaking of the mass of stem
material in water at atmospheric pressure in such a way
as to avoid any substantial loss of water extractible
from the mass. This result may be achieved by
initially exposing the tobacco mass to water for about
5 to about 15 minutes, so as to permit the mass to soak
up the water.
The water has a volume sufficient to permit the
desired moisture content to be achieved and may have
1 157732
any convenient temperature up to the boiling point
thereof, such as about 15 to about 90C, higher
temperatures speeding up the absorbtion of the water.
Thereafter, the exposed mass is stored in confined
manner to permit the soaked up water to permeate
through the mass and into the tobacco stem material
therein and to evenly distribute therethrough. The
confinement may be from about 0.25 to about 24 hours,
preferably about 1 to about 4 hours.
Alternatively, the tobacco mass may be exposed to
water in a suitable conditioning drum for a period
sufficient to achieve the desired overall moisture
content.
The mass of soaked stem material resulting from
the preliminary step is mechanically fiberized between
closely-spaced fiberizing surfaces at atmospheric
pressure to form shredded tobacco stem material in
substantially fibrous form.
This mechanical fiberizing step is quite different
from that adopted in U.S. Patent No. 4,094,323 where a
superatmospheric pressure and high temperature
operation is adopted. In the method used herein, an
atmospheric pressure operation and much lower
temperatures are used, leading to simpler equipment and
less energy requirement. The effects of these
differences are quite significant, in that a shredded
stem material is produced which has properties which
are quite different from and superior to those
exhibited by the prior art product, as discussed in
detail above, and, further, less particulate material
is produced in the method as compared with the prior
art.
Apparatus suitable for carrying out the mechanical
fiberizing step is a revolving double disc refiner,
3S such as are manufactured by Bauer Bros., Sprout-Waldron
and American Defibrator. The disc refiner includes two
disc-like counter-rotating plates which are closely
spaced apart, and at least one has a face pattern
designed to fiberize the material fed between the
1 15773~
plates. The counter-rotating plates of the disc
refiner are spaced apart about 0.05 to about 0.3
inches, preferably 0.13 to 0.18 inches. The optimum
plate-spacing and pattern, rotational speed and
retention time are readily determined for a particular
tobacco stem material and type of disc refiner used.
The product resulting from the refiner generally has
the appearance and size of shredded tobacco lamina,
namely, bundles of loosely integrated fibres.
Some temperature rise results in the mechanical
fiberizing step, as a result of the friction between
the plate ribs and the tobacco stem material. The
soaked mass of tobacco stem material may be fed to the
mechanical fiberizing step at any convenient
temperature up to the boiling point of the water.
The effect of such heat on the final product is to
increase the filling power and pressure drop parameters
and at the same time increase the burn rate. The
temperature of the mass, therefore, may be used to vary
2~ the parameters possessed by the product.
The temperature usually ranges from about 15 to
about 90C. When lower temperature operations are
desired, the temperature of the mass entering the
mechanical fiberizing step may vary from about 10 to
about 35C, preferably about 15 to about 25C.
The shredded tobacco stem material which is formed
in the mechanical fiberizing step is dried to a desired
moisture level in any desired manner. Usually, the
final moisture level is in the range of about 10 to
about 16% by weight, preferably about 12 to about 15%
by weight, since smoking products, such as, cigarettes,
have moisture contents in this range. No initial
separation of particulates is required.
The shredded stem material may be dried to the
3~ final moisture level prior to blending with shredded
tobacco lamina, usually in the proportions of about 2
to about 50 wt.% of shredded stem material and the
balance by weight of shredded tobacco lamina, or may be
partially dried to an intermediate moisture level,
1 157732
11
blended with shredded tobacco lamina at a similar
moisture level, and drying the blend to the desired
moisture level.
In one preferred embodiment of the invention, the
shredded stem material is discharged directly from the
disc refiner into a flowing air stream to maintain the
fibres in a substantially separated condition. This
action may be combined with cooling of the shredded
material by using an air stream having a temperature
below that of the exiting shredded stem material, for
example, about 20 to 25C.
The maintenance of the fibres in a separated
condition decreases the incidence of "balling", or the
joining together and curling up of the fibres to form
ball-like particles which are unusable in the final
product. Once the shredded fibres have been discharged
from the air stream, for example, using a flexible
shell air-lock, they are dried, initially to a moisture
level of about 19 to about 35~ by weight, using any
conventional tobacco drying equipment, such as, a
rotary tumbler drier.
Thereafter, any ball-like particles are removed
from the fibres by any conventional winnowing
technique, such as, by air separation and recycled to
the refiner. The shredded stem material now may be
dried to the final moisture level, or may be blended
with shredded tobacco lamina and the blend dried to the
final moisture level.
The method embodiment of this invention,
therefore, permits shredded tobacco stem material in
substantially fibrous form to be produced without the
substantial production of dust and without the
necessity for high pressure and high pressure
operation. Further, the shredded tobacco stem material
35 which results is superior in its unique combination of
properties to any other known processed tobacco stem
material.
The invention is illustrated by the following
Examples:
~ 1S7732
12
Example 1
Tobacco stem material was placed in a conditioning
cylinder with water for about 8 minutes before being
transferred to a vessel wherein the material was
allowed to stand for about 4 hours, at the end of which
time the stem material had a moisture content of about
55 wt.%.
The soaked stem material was fed between
counter-rotating discs of a double disc refiner rotated
at 1200 rpm and open to the atmosphere. The refiner
was manufactured by Bauer Bros., the pattern of the
plates were those identified by Bauer as 325 and 326,
and the plate spacing was 0.14 inches. After shredding
the material was dried to a moisture content of 14.5
wt.%.
A number of tobacco samples were made up into 850
mg cigarettes using a blend of shredded tobacco lamina
and the shredded tobacco stem material produced by the
above process (Inventive stem), the shredded stem
material alone, shredded tobacco lamina, enhanced CRS
and a blend of shredded tobacco lamina and enhanced
CRS. The burning rate of the cigarettes were
determined under abnormally low moisture levels of
about 9 wt.%. The results are reproduced in the
25 following Table I:
TABLE I
Tobacco Sample Burning Time Burn Rate (2)
(mins.) (1) (mg/min)
100% lamina 15.6 51
75% lamina + 25%
enhanced CRS 12.5 63
75~ lamina + 25%
Inventive Stem13.5 58.9
100% enhanced CRS 9.1 87
35 100% Inventive Stem 11.8 67.4
Notes: (1) Average of 3 runs
(2) These results are higher than normal for all
samples because of the relatively low
moisture level.
1 157732
13
The results of the above Table I demonstrate that
the product containing the inventive shredded stem
material produced lower burning rates than the
corresponding product containing conventional enhanced
CRS. It was observed that the ash formed on burning of
the cigarettes containing the inventive shredded stem
material was much stronger than the ash formed on
burning the other cigarettes.
Example 2
Cigarettes were prepared from blends of 74% lamina
and 26% of stem material, using, in one case, enhanced
cut-rolled stem and, in another case, the inventive
shredded stem material. The cigarettes were smoked and
determination of tar, nicotine and carbon monoxide in
the smoke were made. The results are reproduced in the
following Table II:
1 15773~
14
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1 157732
The results of the above Table II show a
significant decrease in carbon monoxide content of the
smoke, the difference being 14.4% between the samples.
While this decrease in carbon monoxide is obtained, the
tar and nicotine values in the smoke remained
substantially unaffected in this test.
Example 3
Samples of cigarettes were made prepared under
production conditions from mixtures of lamina and stem
material as described in Example 2. An increased
number of tests were carried out on the samples than
was effected in the case of Example 2. The results are
reproduced in the following Table III:
TABLE III
15 Parameter Samples
with inventive with enhanced
stem material cut-rolled stem
Dry tar mg/cgt 15.3 14.3
Nicotine mg/cgt 1.03 0.81
CO mg/cgt 16.6 19.7
No. of puffs/cgt 10.8 9.5
CO/puff (mg) 1.54 2.07
Tar/puff (mg) 1.41 1.50
Nicotine/puff (mg) 0.095 0.085
Weight - total g 1.121 1.125
- tobacco rod g 0.965 0.968
- filter g 0.156 0.157
Pressure drop - total cm11.4 12.1
- total rod cm 5.0 5.5
- filter cm6.6 6.8
Rod diameter mm 7.95 7.96
Free Burn - (min.sec/40 mm) 10:40 9:08
Burn rate (mg/min~ 54.0 63.2
% Nicotine 1.58 1.49
% Nicotine/puff 0.146 0.146
35 % Sugar 18.3 17.6
% Sugar/puff 1.69 1.85
% Chloride 1.39 1.64
~ Chloride/puff 0.128 0.172
1 157732
16
The results of the above Table III confirm the
superiority of the inventive stem material under
production conditions. A slower burning rate is
observed along with a lower carbon monoxide content in
the cigarette smoke, and a decreased pressure drop.
Example 4
Samples of shredded stem material were again
produced following the procedure of Example 1, except
that the water in the conditioning drum had a
temperature of about 70C, some soaked samples were
shredded at ambient temperature while other soaked
samples were shredded at an elevated temperature of
about 80~C, and drying was effected in a rotary drier.
The samples were subjected to sieve test~, which
showed that about 20 wt.% of the material passed an
18-mesh screen. This fine particulate material was
retained with the samples for testing.
Cigarette samples containing a tobacco weight of
865 mg, a tobacco length of 67 mm of which 40 mm was
smoked were made up containing Inventive Stem produced
at ambient temperature, Inventive Stem produced at
elevated temperature, enhanced CRS, CRS and shredded
tobacco lamina. The cigarettes were smoked and
determinations were made on the smoke. The results are
reproduced in the following Table IV:
~ 157732
17
.~ o 1~ ~ ~ O ~
Ut
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O ~ O ~ ~ ~ ~ O
~O CO ~i 0 0 Il~ ~ ~D ~i
~ _l
a~
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rl Q I` ~I ~ ~ o ~1 ~ o u~ 1` u~
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er U~ O O O i` O ~ O
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1 157732
The results of the above Table IV illustrate the
superior combination of properties of both the shredded
stem produced at ambient and at elevated temperatures,
when compared with CRS and enhanced CRS. Burn rate is
significantly decreased, CO, tar and nicotine smoke
contents are significant~y decreased, the pressure drop
is less than enhanced CRS although not as low as CRS
and the bulk filling power is significantly greater.
The inventive stem material produced at an
elevated temperature feed exhibits a faster burn rate,
higher CO, tar and nicotine smoke contents, or higher
pressure drop and a higher filling power when compared
with the inventive stem material produced at an ambient
temperature feed, illustrating the ability to modify
the superior properties of the shredded stem material
of the invention by altering the refining temperature.
Example 5
A number of 85 mm length cigarette samples were
prepared using conventional CRS and inventive stem
material, produced under both cold and hot feed
conditions to the refiner as described in Example 4.
The cigarettes were smoked and, in each case,
determination of burning rate and pressure drop were
made. The values obtained were compared with each
other and also with the values for these parameters as
they are set forth in U.S. Patent 4,094,323 for both
fiberized and expanded stem and CRS.
The results are reproduced in the following Table
V wherein the density for shredded stem and fiberized
stem cigarettes was 0.215 g/cc while that for CRS
cigarettes was 0.293 g/cc.
3~
1 157732
TABLE V
Inventive Stem Fiber Stem Conventional CRS
Cold Hot U.S.Patent U.S.Patent Same
` 4,094 3234 094,323 Stem
Burn Rate
(mg/min) 50.2 55.6 83.6 75.5 79.9
Pressure
10 Drop (cm of
Hg) 2.6 3.2 4.1 4.1 3.8
The results of the above Table V show the very
much lower burning rate attained by the shredded stem
material of this invention, produced from either a cold
feed or a hot feed to the disc refiner, when compared
with the other products.
The pressure drop for the inventive material is
less than for enhanced CRS and fiberized expanded
material produced by the procedure of U.S. Patent
4,094,323.
Example 6
The filling power of shredded stem material
produced from both a cold feed and a hot feed as
described in Example 4 was determined both for samples
2S wherein particulate material passing an 18-mesh screen
was sieved from the material and for samples wherein
the particulate material was retained. These values
were compared with those set forth in U.S. Patent No.
4,094,323 for fiberized and expanded stem at a density
of 0.215 g/cc and with tho-se for conventional CRS as
set forth in U.S. Patent No. 4,094,323 and as produced
from the same stem material at a density of 0.293 g/cc.
The results are reproduced in the following Table
VI:
~ 157732
o ~o ~ `
~ d'
8 u~ o
U D er
U~~ U~
`
U~
o n
1~ D ~
~ ~ ~ O 1` U~
H U~ ~53 ~
~ .~
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E~ S ~ ~ R u~ o
dP
b ~ ~
1 157732
21
As can be seen from the results set forth in Table
VI, the sieving out of the fine particulates from the
shredded stem material imprcves the filling power
thereof by about 10%. The % increase in filling power
over the base CRS material for the sieved inventive
stem material exceeds % increase in filling power of
the sieved fiberized and expanded stem material of U.S.
Patent 4,094,323 over the CRS material described
therein.
In summary of this disclosure, the present
invention provides a novel shredded tobacco stem
material useful in manufacture of cigarettes.
Modifications are possible within the scope of this
invention.
