Note: Descriptions are shown in the official language in which they were submitted.
-s- 134145
IMPROVEMENTS RELATING TO SMOKING ARTICLES
The invention the subject of this application
relates to cigarettes and similar smoking articles.
The present application is divided from Canadian
Patent Application Serial No. 576,464 filed September 2,
1988.
In United Kingdom Patent Specification No. 2 175
789A there is a disclosure to the effect that cigarettes
having a circumference within a range of 10 mm to 19 mm
and a free burn rate of the cigarette rod of 25 to 50 mg
min' exhibit lower smoke component sidestream deliveries
than do comparable conventional cigarettes.
There are disclosed in United Kingdom Patent
Specification No. 2 094 130A cigarettes comprising
cigarette papers having air permeabilities due to viscous
flow of not more than 3 Coresta Units and Dolt ratios in
a range of 0.08 to 0.65 cm sec-', where Do signifies the
coefficient of diffusion of oxygen through nitrogen in
the paper and t signifies the thickness of the cigarette
paper. Such cigarettes exhibit low deliveries of total
particulate matter and nicotine in the sidestream smoke.
A further approach to the obtainment of low
component deliveries in the sidestream smoke of
cigarettes is by way of using cigarette papers comprising
one or more sidestream reducing compounds. Thus, for
example, there is a teaching in United Kingdom Patent
Specification No. 2 139 869A that the total particulate
matter in the sidestream smoke emanating from the lit end
of a cigarette during the smoking thereof can be reduced
by
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at least 30~ if the cigarette paper comprises one or
more, preferably a plurality, of compounds of the
group consisting of lithium hydroxide, aluminium
hydroxide, calcium hydroxide, potassium formate, sodium
formate and sodium acetate.
Another example of the use of sidestream reducing
compounds is disclosed in United States Patent
Specification No. 4,231,3??, according to the teaching
of which magnesium oxide and an adjuvant salt are
incorporated in combination in cigarette paper.
It is an object of the subject invention to provide
an improved low sidestream cigarette or similar smoking
article.
The subject invention provides a smoking article
comprising a smoking material rod, which rod comprises
smoking material and a wrapper circumscribing said
smoking material, said rod not exceeding 20 mm in
circumference and said wrapper being of a material
comprising a sidestream reducing compound, said
material being such that when providing a wrapper of a
smoking material rod of conventional cigarette
circumference there is effected a reduction of at
least 30~ in the particulate matter, on a water and
nicotine free basis, of sidestream smoke compared with
a control rod of the same conventional cigarette circum
ference and comprising conventional cigarette paper.
The sidestream reducing compound is effective to
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reduce visible sidestream smoke components without
effecting a marked, if any, reduction in gas phase
components of sidestream smoke. Among the compounds
which can be used, singly or in combination, as
sidestream reducing compounds are aluminium hydroxide,
calcium hydroxide, lithium hydroxide, magnesium
hydroxide, magnesium oxide, alumina and Attapulgite
clay. Other compounds which can be used as sidestream
reducing compounds are disclosed in United States
Patent Specification No. 4,461,311, to which reference
is directed.
Suitably, the material of wrappers of smoking
articles according to the present invention is paper.
Water insoluble sidestream reducing compounds may be
1~ added in powder form as a filler to the paper furnish
during the making process of paper wrapper material.
Water soluble sidestream reducing compounds are
preferably applied to the wrapper material in aqueous
solution.
The smoking material of smoking articles according
to the subject invention preferably comprises or consists
of cut tobacco, a proportion of which tobacco may be
expanded tobacco. The smoking material may comprise
reconstituted tobacco or tobacco substitute material.
The length of the smoking material rod is
advantageously at least 60 mm and the rod should
preferably yield not less than six puffs, and more
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preferably not less than seven puffs when smoked
under standard machine smoking conditions. The
rod is preferably of uniform cross-sectional shape
and dimensions throughout the length of the rod.
If the rod is of circular cross-section, the
circumference of the rod may be as low as 10 mm
for example, but is preferably not less than
12.5 mm.
Advantageously, the circumference of the
smoking material rod does not exceed about 19 mm
and more advantageously it may be less than 18 mm.
Preferably, cigarettes according to the
subject invention comprise filter or mouthpiece means
attached to the smoking material rod at one end
thereof.
Preferably, wrappers of smoking articles according
to the present invention are of a low permeability, the
permeability thereof being, for example, not more than
Coresta Units, and more preferably not more than 12
20 Coresta Units.
In order to further the understanding of the
present invention, examples according thereto will now
be described.
EXAMPLE I
There was produced a cigarette consisting of a
20 mm circumference cigarette rod of 64 mm length and
a cellulose acetate filter of 20 mm length attached
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to the rod by means of a tipping wrapper. The rod
comprised a cut tobacco filler having a density of
240 mg cm-3, which filler was wrapped in a circum-
scribing cigarette paper wrapper of 19 Coresta Units
permeability and a substance of 45 gm m-2. The
cigarette paper wrapper comprised 230 chalk, 8~
magnesium hydroxide and 2~ sodium acetate. When
these cigarettes were smoked under standard machine
smoking conditions, i.e. a 35 cm3 puff of 2 seconds
1U duration every minute, to a cigarette rod butt 8 mm
long, the total yield of sidestream particulate
matter, on a water and nicotine free basis, was 9.2
mg, the total yield of sidestream carbon monoxide
being 34.3 mg. The number of puffs during smoking
was 8.9.
EXAMPLE II
Cigarettes were produced consisting of 20 mm
circumference, 64 mm long cigarette rods and 20 mm
long cellulose acetate filters attached to the rods by
tipping wrappers. The cigarette rods comprised a cut
tobacco filler of a density of 287 mg cm-3 and cigarette
paper wrappers of 11 Coresta Units permeability and a
substance of 43 gm-2. The cigarette paper wrapper
comprised 19.7' chalk, 5.U'% magnesium oxide and 6.7~
citrate tri-potassium (expressed as ~ anhydrous citric
acid). These cigarettes, smoked under standard machine
smoking conditions, produced a total yield of sidestream
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particulate matter, water and nicotine free, of 13.3
mg and a total yield of sidestream carbon monoxide of
36.8 mg. The cigarettes yielded 8.3 puffs.
EXAMPLE III
Cigarettes were produced consisting of 17 mm
circumference, 70 mm long cigarette rods and 27 mm
long cellulose acetate filters. The density of the cut
tobacco filler of the cigarette rods was 293 mg cm-3.
The cigarette rod wrappers were of cigarette paper of
26 Coresta Units permeability and a substance of 26
g m-2. The paper did not contain sidestream reducing
compounds. Some of these cigarettes were overwrapped
with a second cigarette paper, which second paper was
of 15 Coresta Units permeability and of a basis weight
of 50 g m-2. The second paper comprised 4.5~ chalk,
24.3 magnesium hydroxide and 3.6~ sodium acetate.
When the overwrapped cigarettes were smoked under
standard smoking conditions it was determined that each
produced a total yield of sidestream particulate matter,
water and nicotine free, of 8.3 mg and total yields of
sidestream carbon monoxide and nicotine of 39.1 mg and
1.1 mg respectively. The puff number of the overwrapped
cigarettes was 12. When the non-overwrapped cigarettes
were smoked under the same conditions, the total yields
of sidestream particulate matter, water and nicotine
free, carbon monoxide and nicotine were 20.7 mg,
45 mg and 2.7 mg respectively.
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Two types of control cigarette were smoked, each
having a 64 mm long cigarette rod of a conventional
24.75 mm circumference. The first type of control
cigarette comprised a conventional cigarette paper
wrapper of 47 Coresta Units permeability, a substance
of 25 gm-2, the wrapper comprising 26~ chalk and 0.8~
tri-potassium citrate. When the first type of control
cigarette was smoked under standard smoking conditions,
it was found to deliver a total yield of sidestream
nicotine of 4.9 mg. As noted above, the total sidestream
nicotine delivery for the non-overwrapped 1? mm
cigarettes was 2.7 mg. It may thus be observed that
with the cigarettes comprising conventional cigarette
paper wrappers, a reduction of cigarette rod circumference
to an unconventional 17 mm, from a conventional 24.75
mm, reduces the sidestream nicotine by 45~.
The second type of control cigarette comprised a
cigarette paper wrapper of the same type of paper as
used to overwrap the above mentioned overwrapped 17 mm
cigarettes. When the second type of control cigarette
was smoked under standard smoking conditions, it was
found to deliver a total yield of sidestream nicotine
of 2.5 mg. When this sidestream nicotine yield is
compared with that of the first type of control
cigarette, it may be observed that the substitution of
the sidestream reducing cigarette paper for the conven-
tional cigarette paper of the first type of control
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cigarette effects a 49~ reduction in sidestream nicotine
yield.
From the above it would be expected that by
combining in a single cigarette the two sidestream
nicotine reducing features, namely a reduction in
cigarette circumference from 24.75 mm to 1? mm and the
substitution of a conventional cigarette paper by a
sidestream reducing cigarette paper, that the tota l
sidestream nicotine yield would be reduced to 28~ of
that of a conventional cigarette comprising neither of
the features, which conventional cigarette is represented
by the first type of control cigarette. In point of
fact though, the l7 mm circumference overwrapped
cigarettes, which, of course, do comprise each of the
two sidestream reducing features, effect a reduction in
total sidestream nicotine yield to a value, namely 1.1
mg, which is 22.5 of that of the first type of control
cigarette. Thus the overwrapped 17 mm circumference
cigarettes exhibited a synergistic sidestream nicotine
reduction effect.
EXAMPLE IV
Cigarettes were produced consisting of 24.75 mm
circumference, 64 mm long cigarette rods and 20 mm long
cellulose acetate filters. The density of the cut
tobacco filler of the cigarette rods was 279 mg cm-3.
The cigarette rod wrappers were of a conventional
cigarette paper of 47 Coresta Units permeability and a
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substance of 25 g m-2. The paper comprised 26~
calcium carbonate filler and 0.81 of burn additive
consisting of a mixture of potassium citrate and sodium
citrate, expressed as percentage citric acid. These
cigarettes were designated Cigarettes A.
Second cigarettes, designated Cigarettes B, were
produced, the Cigarettes B being in all particulars the
same as the Cigarettes A excepting that the cigarette
rod wrappers of the Cigarettes ~3 were of a sidestream
reducing paper of 19 Coresta Units permeability and a
substance of 44.8 g m-2. The sidestream reducing
paper comprised 8.2~ magnesium hydroxide, 21.8 calcium
carbonate and 2.02 sodium acetate.
Cigarettes C were produced, which cigarettes were
the same as Cigarettes A in all particulars excepting
that the Cigarettes C were of a circumference of 17 mm.
Cigarettes D were produced, which cigarettes were
the same as Cigarettes C in all particulars excepting
that the cigarette rod wrappers of the Cigarettes D
were of the same paper as that of the cigarette rod
wrappers of the Cigarettes B. Cigarettes D were
cigarettes in accordance with the subject invention.
The Cigarettes A-D were smoked under standard
machine smoking conditions and measurements were made
of the total sidestream yields per cigarette of
particulate matter, on a water and nicotine free basis
(PMWNF), total nicotine alkaloids (TNA) and carbon
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monoxide (CO). The measured values are given in Table 1.
The predicted values shown in Table 1 for Cigarettes
D were calculated from the measured values for Cigarettes
A-C. Thus, for example, the predicted value of PMWNF for
Cigarettes D is calculated as -
18.5 mg x 15.8 = 8 mg
36.5
The measured value of PMWNF for Cigarettes D was
7.0 mg. It is thus seen that in both reducing the
diameter of a cigarette and providing a sidestream
reducing wrapper therefor in accordance with the
subject invention there is effected a synergistic
reduction in sidestream PMWNF. As Table 1 also shows,
Cigarettes D in accordance with the subject invention
also exhibit synergistic reductions in sidestream TNA
and CO.
The average puff number of Cigarettes D was 10.8.
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TABLE 1
PMWNF TNA CO
Cigarette
mg mg mg
A 36.5 7.72 62.1
B 15.8 5.43 60.1
C 18.5 3.29 42.4
D 8.0 2.30 41.1
Predicted
D 7.0 2.17 36.1
Measured
EXAMPLE V
Cigarettes E were produced consisting of 24.75 mm
circumference, 64 mm long cigarette rods and 20 mm
long cellulose acetate filters. The density of the
cut tobacco filler of the cigarette rods, which filler
contained 12~ by weight of DIET expanded tobacco, was
252 mg cm-3. The cigarette rod wrappers of the
Cigarettes E were of the same conventional cigarette
paper as was used for the Cigarettes A of Example IV.
Cigarettes F were produced, which were the same in
all particulars as the Cigarettes B except for the use
in Cigarettes F of cigarette paper of 18 Coresta Units
permeability and 47.4 g m-2 substance and comprising
33.3 magnesium hydroxide, 5.3~ calcium carbonate,
5.3~ potassium acetate and 1.1~ sodium acetate.
Cigarettes G were the same in all particulars as
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Cigarettes E excepting that Cigarettes G were of a
circumference of 17 mm and the cut tobacco filler
contained 40~ by weight DIET expanded tobacco, the
density of the filler being 224 g cm-3.
Cigarettes H were the same as Cigarettes G in all
particulars excepting that the cigarette rod wrappers
of Cigarettes H were of the same sidestream reducing
paper as that of Cigarettes F. Cigarettes H were
cigarettes in accordance with the subject invention.
The Cigarettes E to H were smoked under standard
machine smoking conditions and determinations were made
of the total sidestream yields per cigarette of PMWNF,
TNA and C0. The measured values are given in Table 2.
The predicted values for Cigarettes H were calculated
in the same fashion as is detailed above in respect of
Cigarettes D.
It is to be observed of Table 2 that Cigarettes H
in accordance with the subject invention exhibit
synergistic reductions in sidestream PMWNF, TNA and C0.
Cigarettes H also exhibited a synergistic reduction for
sidestream carbon dioxide.
The average puff number of Cigarettes H was 6.8.
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TABLE 2
PMWNF TNA CO
Cigarette mg mg mg
E 25.6 5.45 58.6
F 11.8 3.79 51.5
G 14.6 2.40 3U.4
H 6.? 1.68 26.7
Predicted
H 5.3 1.15 25.9
Measured
EXAMPLE VI
Cigarettes I were produced consisting of 24.75 mm
circumference, 64 mm long cigarette rods and 20 mm long
cellulose acetate filters. The density of the cut
tobacco filler of the cigarette rods was 291 mg cm-3.
The cigarette rod wrappers of the Cigarettes I were of
the same conventional cigarette paper as was used for
the Cigarettes A of Example IV.
Cigarettes J were produced, which were the same in
a1.1 particulars as the Cigarettes I except for the use
in Cigarettes J of cigarette paper of 5 Coresta units
permeability and 45.0 substance and comprising 16~
Attapulgite clay, 18~ calcium carbonate, 11~ tri-
potassium citrate and 3~ monoammonium phosphate.
Cigarettes K were the same in all particulars as
Cigarettes I excepting that Cigarettes K were of a
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circumference of 1? mm.
Cigarettes L were the same as Cigarettes K in all
particulars excepting that the cigarette rod wrappers
of Cigarettes L were of the same sidestream reducing
paper as that of Cigarettes J. Cigarettes L were
cigarettes in accordance with the subject invention.
The Cigarettes I to L were smoked under standard
machine smoking conditions and determinations were made
of the total sidestream yields per cigarette of PMWNF,
1U TNA and CO, the values of which are given in Table 3.
It is to be observed of Table 3 that Cigarettes L
in accordance with the subject invention exhibit
synergistic reductions in sidestream TNA and C0.
The average puff number of Cigarettes L was 13Ø
TABLE 3
PMWNF TNA CO
Cigarette
mg mg mg
I 33.7 4.9 Ei7.0
J 13.5 2.7 49.0
K 18.5 3.29 42.4
L ' 7.4 1.81 31.0
Rredicted
L 9.8 1.73 25.6
Measured
Figure 1 of the diagrammatic drawings hereof shows
apparatus used in making determinations of deliveries
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of sidestream smoke components and Figures 2 to 5 show
a fishtail chimney forming part of the apparatus shown
in Figure 1, Figures 3 to 5 being views on Figure 2
taken in the directions of arrows A, B and C respectively.
The apparatus shown in Figure 1 which was used in
making the determinations of the above cited deliveries
of sidestream smoke components comprised a Filtrona*302
linear smoking machine 7, a port of which is designated
by reference numeral 8. At each port of the smoking
machine 7 there was vertically disposed an open ended,
glass fishtail chimney, that associated with port 8
being designated by reference numeral J. In Figure 2
dimensions a and b are 410 mm and 8U mm respectively.
In Figure 3 internal dimension (diameter) c is 24 mm
and dimension d is 22 mm. Transversely disposed above
chimney 9 was a pre-weighed Cambridge filter pad 10.
The item designated by reference numeral 10' is a
Cambridge filter pad utilised in the measurement of
mainstream smoke component deliveries. A tube 11
extended from the upper side of the filter pad 10 to a
gas-flow meter 12, from which meter 12 a tube 13
extended to a gas pump 14. Connected to the pipe 13
by inlet and outlet tubes 15, 16 was an infrared carbon
monoxide analyser 17 embodying an internal gas
circulation pump (not shown).
In operation of the Figure 1 apparatus, for the
determination of sidestream smoke component deliveries
Trade-mark*
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of a cigarette 18 smoked at the port 8 of the smoking
machine 7, the pump 14 was set to provide a flow rate
through chimney 9, tube 11 and tube 13 of 2.0 litres
per minute. During the smoking of the cigarette 18
under standard smoking conditions at the port 8 the
sidestream smoke emanating from the cigarette 18 passed
up the chimney 9 to the filter pad 10. That portion of
the smoke not deposited at the pad 10 or on the interior
walls of the chimney 9 passed through tubes 11, 13 and
a sub-sample thereof passed through the carbon monoxide
analyser 1? by way of the inlet and outlet tubes 15, 16.
When the smoking at port 8 of the cigarette 18 and
two identical cigarettes had been completed, the pad 10
was re-weighed. t~'rom the weight so determined there was
subtracted the original weight of the pad 10, thus to
give the weight of total particulate matter (TPM) de-
posited on the pad 10. The pad 10 was then extracted
with an extracting solvent, propan-2-of for example.
The extract so obtain was analysed by gas chromatography
to determine the amounds of nicotine and water deposited
on the pad 10. The sum of the weights so determined of
nicotine and water was subtracted from the above mentioned
gravimetrically determined weight of TPM deposited on
the pad 10, thus to give the weight of PMWNF there
deposited.
The interior of the chimney 9 was rinsed with an
extracting solvent, propan-2-of for example. A portion
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of the extract so obtained was analysed by gas
chromatography to determine the amount of nicotine
deposited on the interior walls of the chimney 9. The
weight of nicotine so determined was added to the weight
of nicotine deposited on the pad 10, thus to give the
total weight of sidestream nicotine produced from the
three cigarettes, which weight was divided by three
to give the weight of sidestream nicotine per cigarette.
The other portion of the extract obtained from the
rinsing of the chimney 9 was analysed by an ultra violet
technique, in which as.a standard was employed a portion
of the above referred to extract obtained from the pad
1U, to determine the amount of PMWNF deposited on the
interior walls of the chimney 9. The weight of PMWNF
so determined was added to the weight of PMWNF, as
above determined, deposited on the pad 10, thus to give
the total weight of sidestream PMWNF produced from the
three cigarettes, which weight was divided by three to
give the weight of sidestream PMWNF per cigarette.
The sidestream smoke CO yield per cigarette was
determined from data obtained from the analyser 17.
