Note: Descriptions are shown in the official language in which they were submitted.
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SMOKING ARTICLES
This invention relates to smoking articles such
as cigarettes, cigars and cigarillos, and is concerned
with the reduction of sidestream smoke from smoking
articles. Sidestream smoke is that which is produced
when the article is alight but not being drawn on by
the smoker. Mainstream smoke is that which is
generated when the smoking article is drawn on by the
smoker; the chemistries of mainstream and sidestream
smokes are different.
Sidestream smoke is perceived to be annoying to
non-smokers, especially when a cigarette is left lying
as for example in an ashtray, and any reduction in it
is desirable. The modification of mainstream smoke
affects the perception of the article by the smoker.
The present invention uses activated carbon to
modify the smoke of a smoking article. Of course,
activated carbon has been used in smoking articles, and
for various purposes, virtually ever since its
excellent adsorbent properties became known.
For example, the effects of various carbon
contents of filters have been investigated by Williams
et al in a report presented to the 5th General Assembly
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of CORESTA, Vienna, October 1964 and reprinted in
Beitrage zur Tabakforschung, Vol. 3 part ~,, pages 233-
242. This showed varying adsorbence of different
constituents of mainstream smoke by filter shreds of
different make-up. However we are concerned with
placing of carbon in the tobacco rod; that is, where it
is subjected to conditions very different from those in
a filter.
GB-A-1512352 shows the use of activated porous
particles of carbon adhered to tobacco in the tobacco
rod to affect mainstream smoke. GB-A-1348580 shows a
sheet of reconstituted~tobacco material containing
activated carbon used as a main material for making
cigarettes which gave a reduction in particulates and
nicotine in mainstream smoke.
As far as we are aware at present the only
disclosure of the use of carbon in a tobacco rod in a
situation where reduction of sidestream smoke was aimed
for is in US-A-5092353 (EP-A-378774). However the aim
in that disclosure was to reduce sidestream smoke by
the use of wrapping paper of very low permeability (<
10 CORESTA units). To compensate for the tendency this
will cause for the cigarette to be self-extinguishing,
pyrolyzed alpha-cellulose was present in the tobacco
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rod.
This pyrolyzed material was not subject to any
activating treatment. No mention is made of any chemical
effect it might have on the smoke, and it probably has
little or none because in the specific example the pyrolyzed
material was cotton linters, which would give a
comparatively low surface-area carbon.
Various embodiments of this invention provide a
smoking article having a tobacco rod which comprises a blend
of shredded tobacco and shredded reconstituted tobacco
sheet, the reconstituted tobacco sheet containing activated
carbon particles, and a wrapper around the tobacco rod, the
wrapper having an inherent permeability of 20 CORESTA or
greater.
Other embodiments of this invention provide a
method of producing a smoking article with reduced
sidestream smoke and increased perceived mildness during
smoking which includes using for a tobacco rod of the
article shredded tobacco and shredded reconstituted tobacco
sheet containing activated carbon particles, and as a
wrapper of the smoking article a material having an inherent
permeability of 20 CORESTA or greater.
Other embodiments of this invention provide a kit
for hand-rolling a smoking article with reduced sidestream
smoke and increased perceived mildness during smoking which
includes for a tobacco rod of the article shredded tobacco
and shredded reconstituted tobacco sheet containing
activated carbon particles, and as a wrapper of the smoking
article a material having an inherent permeability of 20
CORESTA or greater.
The present invention, therefore, is contrasted
with all of this prior art by providing in a tobacco
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rod an activated carbon for having an effect on the
chemistry of smoke while not being limited to the use
of low permeability papers, and specifically not to
papers of < 10 CORESTA.
Furthermore, the present invention~provides the
addition of activated carbon in specific particulate
form in reconstituted tobacco sheet to the tobacco rod
of the smoking article in such a way that greater
mildness of the smoking article is perceived by the
smoker in the mainstream smoke, and at the same time
there is a reduction in sidestream smoke over a wide
range of porosities of the wrapper of the article and
in particular with porosities high enough that special
precautions do not have to be taken tQ prevent self-
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extinction of the article.
Furthermore, the activated carbon particle
should preferably be of vegetable origin since they
will then contain minute traces of metals, which assist
in the firm adsorption of (particularly) aldehydes from
the smoke and indeed may chelate with such compounds.
These are compounds the removal of which is
particularly critical for improving mildness of
perception of the article when smoked.
At the same time, however, the activated carbon
does not diminish and may even increase certain
beneficial volatile components of the smoke.
It is important to realise that as the ~~coal~~
of the smoking article progresses along the article,
smoke components adsorbed by the particles are
displaced from those particles minimally if at all.
They are destroyed to gaseous oxides together with the
material of the carbon particle itself by the extremely
high temperatures (reaching up to about 800°C)
generated in the coal.
The reconstituted tobacco sheet containing the
activated carbon particles may be made by conventional
techniques for making such sheets, which in their turn
resemble conventional paper-making techniques, the
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sheet then being shredded for incorporation with
shredded tobacco which will be the material of the
tobacco rod.
An important application of the present
5 invention however will be in "roll your own" tobacco
blends, i.e. those which are sold loose and which are
wrapped in cigarette papers by the smoker.
The invention therefore includes within its
scope a blend of shredded tobacco and of reconstituted
tobacco sheet with the latter containing activated
carbon.
The handling of the sheet, whether in shredding
or in later manipulation either in a machine or by the
smoker, may cause loss of carbon particles and the
reconstituted tobacco sheet may be coated or sized in
order to assist retention of the particles in it, and
in particular the particles may themselves be micro-
encapsulated before incorporation. This latter has the
advantage of increasing the size of the particles and
therefore their retention mechanically and the
uniformity of size but, perhaps surprisingly, does not
affect their activity.
Cigarettes were made from a mixture of US flue-
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cured and Burley tobaccos, cut rolled stem and expanded
tobaccos, processed and cut to 32 cuts per inch
("cpi"). Incorporated in the shredded tobacco were 20%
of a reconstituted tobacco sheet equally cut and
containing 30% of activated carbon particles from
coconut, of mean particle size 37 ~.m and ranging in
particle size from 0.5 ~.m to 150 ~,m. Control
cigarettes were made identically but with the omission
of the activated carbon particles.
The cigarettes were 84 rnm long, 7.9 mm
diameter, unfiltered. The wrapping was an 80 CORESTA
flax-based paper, with 2% potassium citrate burn
enhancer.
The cigarettes were subjected to smoking on a
standard smoking machine and the mainstream smoke was
analysed for vapour phase and semi-volatiles content
with the results shown in Tables 1 and 2.
As seen in Table 1, there was a striking
diminution, selective in character, of certain
aldehydes and ketones and in particular of acrolein and
butyraldehydes, the removal of which is important for
mildness of taste. On the other hand, there was an
actual increase as compared to the standard in certain
ingredients, and in particular lirnonene, which are
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regarded as beneficial to the taste.
A similar reduction though less selective is
X seen in the semi-volatiles as shown in Table 2.
xa gle 2
Cigarettes and controls were prepared using the
same tobacco blend and reconstituted tobacco sheet as
in Example 1, but using respectively papers of 25, 50,
80 and 180 CORESTA units porosity. Sidestream smoke
from the inventive cigarettes and from the controls had
significant reductions both in semi-volatiles and in
nicotine content, as seen in Table 3. Increased carbon
monoxide and carbon dioxide production is assumed to be
due to the presence of the particulate carbon in the
tobacco sheet.
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S
VAPOUR PHASE ANALYSIS, RESULTS SUMMARY
(Non-ISO 4387 conditions)
Relative
Peak -
Area
Control Test
Component Mean RSD Mean RSD
Isoprene 30.8 3 30.6 4
l.imonene 2.3 33 2.6 17
Benzene 16.9 5 16.5 3
Toluene 26.7 9 27.3 4
Ethyibenzene 4.1 18 4.5 8
m-+p-Xylene 6.0 19 6.7 8
o-Xylene 1.4 21 1.6 9
Styrene 1.5 28 1.7 14
Acetaldehyde 9.4 ~4 9.3 3
Propionaldehyde 2.6 'T 2.5 7
Acrolein 3.5 4 3.2 5
~
n-Butyraldehyde 0.48 !5 0.44 4
iso-Butyraldehyde 1.3 4 1.2 4
Crotonaldehyde 2.6 9 2.5 6
2-Furaldehyde 1.5 3.7 1.8 20
Acetone 110.2 4 99.0 4
Methylethylketone 29.5 ;5 26.8 4
3-Methyl-2-butanone1.6 ;~ 1.5 5
Diacetyl 55.1 :i 50.2 3
2-Pentanone 0.27 fi 0.25 4
2,3-Pentanedione 3.3 9 3.2 5
Cyclopentanone 2.2 18 2.2 18
Furan 5.7 :3 5.4 4
2-Methylfuran 3.9 4 3.9 3
2,5-Dimethylfuran 6.3 fi 6.4 3
Acetonitrile 12.9 6 12.6 5
Propionitlile 2.5 7 2.5 4
n-Butyronitrile 2.5 8 2.5 12
iso-Butyronitrile 1.1 7 1.1 5
Methacrylonitrile 0.79 4 0.80 5
Pyridine 1.3 43 1.5 20
1-Methylpycrole 1.4 12 1.5 6
Methyldisulphide 0.62 8 0.56 8
Thiophene 0.19 fi 0.19 4
Replicates 12 11
Highlighted values are statistically significantly different at a 95%
confidence limit
(Student-t Test, two-tail)
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TABLE 2
SEMIVOLATILES ANALYSIS, RESULTS SUMMARY
~g/CIGARETTE _
T ~~ s t
Control Test as o oj=
Component Mean RSD Mean RSD con tro :~
Limonene 21.9 13 20.8 10 95
Naphthalene 2.0 3 1.9 5 ~~.:: fi
::::>::~::i~.~;v:;::xa
1-Methylnaphthalene 1.1 3 1.1 5 gg
2-Methylnaphthaiene 1.6 & 1.6 4 gg
:~:t,: '~ ~:.,.~,.,:
Neophytadiene 127.2 7 108.8 3 ,<.:.:;:.,...:::'
:'. . ..,::~
Myosmine 9.3 4 10.1 3
'l':
~...,#<,
Pyrrole 11.3 6 9.6 6
y,~...',.~'..~~~1,...>..~<'~.~.~~W..':..
>;, ,.; ..~
2-Acetylpyrrole 3.9 5 3.6 4 :. %~.::~.:.:s:~ x
:.. . x,:
~' ~Y~
,~cY' 3,.~:;; f; ,~
Indole 9.8 3 9.0 4 <h. . ,. ~,~.,; ~
~~ ~'f'~
n.:: r vfi~~.
q 7. :: J
a$i~< y~i3:'h~! ~L
2-Furaldehyde 51.1 5 41.8 5 ~:: !r .~.
.:v :~ ,~.; ,
2-Acetylfuran 8.6 9 7.2 4
2-Furanmethanol 43.4 7 37.2 7
5-Methyl-?.-furfural 25.9 9 22.6 6 °~
:. ..~~::x
5-Hydroxymethyl-2-furfural 118.7 3 105.4 4 ~> ''
a-An elicalactone .~: r:'
9 23.0 7 19.4 13 ::. ; :.;~~ '~,~..
.f%:, ~ :.:.fr.'~',
Phenol 79.5 4 71.9 4 ~<~ ,:~ip~.
'' :'uj'~. ~ ~' 3:.~~i : . iv $
o-Cresol 17.3 4 14.9 3 ~$ .~..~
-Cresol '
p 27.5 4 24.6 4 >, ff. , .;
m-Cresol 12.0 3 10.5 4 ' ~. .~ ~~~ ' v
,~?.
~:;~,..
2,3,6-Trimethyiphenol 0.6 15 0.5 6
Pyridine 13.0 14 13.2 7 102
Triacetin Nd nld
TEGDA Nd n/d
Propan-1,2-diol 126.6 69 85.3 43 67
Puffs/cig: 9.0 2 8.9 1 '~'_ '' '.~
TPM (mg/cig): 17.9 3 15.5 3 ~, . _ ,~':~ ~,;
Replicates 12 12
Nd - not detected
Detection limits: Triacetin and TEGDA 1 ~g/cigarette
Highlighted values are statistically significantly different at a 95%
confidence limit
(Student-t Test, two-tail)
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TABLE 3
Sidestream measurements
SAMPLE NFDPM % NICOTINE % CO COs
m ci REDUCTION m ci REDUCTION m ci i
25 CORESTA CONTROL 30.1 - 7 m c
00
. - ?6.3 634
TEST 25.5 15 5 18
3 74 0
. . . 80.3 626
50 CORESTA CONTROL 32.5 - 6
55
. - 70.6 6l2
TEST 28.4 12.6 6 7
07 3
. . 76.1 682
80 CORESTA CONTROL 29.1 - 7
09
. - 81.9 62~
TEST 27.5 5.5 6 12
21 4
. , 74.1 6
180 CORESTACONTROL 33.9 - 7 12
03
. - 77.6 630
TEST 27.5 18 07 13
9 6 7
. . . 73.6 653
