Note: Descriptions are shown in the official language in which they were submitted.
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
1
SMOKING ARTICLE
This invention relates to a smoking article.
Modern smoking articles aim to reduce the delivery of tar, carbon monoxide
and other vapour phase components. Using cigarettes as an example, the quest
for
controlled delivery is typically achieved by altering blend choice, envelope
ventilation,
tip ventilation, filtration and filter adsorbents such as activated carbon.
These
methods, however, are known to compromise the delivery of other cigarette
components, or 'smoke supplement compositions', for example flavour. This is
detrimental to characteristics such as taste, in particular with regard to
high ventilation,
low tar type products.
Methods of combatting the above-described detriment to qualities such as
taste are known, for example by introducing additional flavours into either
the blend
or the filter. Both of these options, however, can exhibit disadvantages such
as the
reduction of filter effectiveness due to the presence of flavour in (or the
migration of
flavour to) the filter or the filter adsorbents, the incomplete transfer of
flavour to the
smoker (for example due to combustion of the flavour, or due to extraction of
the
flavour by the filter), and the dilution of the flavour by other vapours
produced by the
smoking article. Since the introduction of additional flavour is an expensive
process,
maximum transfer of this flavour to the smoker is of utmost importance.
It is therefore necessary to formulate an improved method of introducing
smoke supplement compositions such as flavour into smoking articles, such that
the
detriment to qualities such as taste which can occur in association with the
controlled
delivery of for example tar and carbon monoxide can be effectively overcome
without
the above-mentioned disadvantages.
The present invention provides a smoking article comprising a distal end
which,
in use, contains a smoke producing substance, a proximal end from which the
smoke
is drawn during smoking, and at least one channel which runs from the proximal
end
to at least partway towards the distal end. At least one vent hole is arranged
such that
an airflow path is defined through the vent hole, via the channel, and to the
proximal
end of the smoking article. A smoke supplement composition is housed along
this
airflow path, such that, when the smoking article is smoked, air is drawn
along the
airflow path and over the composition so that the composition becomes airborne
and
is delivered to the smoker.
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
2
Such a smoking article exhibits what will now be termed as a "parallel
delivery
system", ie. a system wherein a smoke supplement composition such as flavour,
nicotine, nicotine derivatives, pharmacologically active agents or smoke
modifiers is
delivered parallel to, rather than in series with, smoke from the smoke
producing
substance. Such a "parallel delivery system" improves delivery of the smoke
supplement composition, and in the case of delivery of flavour, this improves
the
flavour of the smoking article while overcoming the problems associated with
prior art
flavour improvement methods.
In detail, the present invention does not give rise to pyrolysis or combustion
of
the smoke supplement composition since the composition receives at most only
mild
heating. Migration of the composition to other parts of the smoking article is
reduced
since the composition is confined to the airflow path, and delivery of the
composition
is not hindered by dilution with other vapours from the smoking article - in
contrast
delivery is most effective at high dilution levels, ie. when airflow is high.
Furthermore, the composition is not subject to significant filtration, there
is a
fixed amount of composition, and blocking the ventilation holes actually
reduces
delivery of the composition rather than increasing it.
Smoking articles according to.the present invention include cigars,
cigarettes,
hookahs and pipes, and preferably the smoking article of the present invention
is a
cigarette. It is additionally envisaged that smoking articles which require
the final
stages of their manufacture to be performed by the smoker, for example ready
formed
hollow tubes containing a filter into which a smoker inserts tobacco, are also
within the
scope of the invention. Further 'roll your own' or 'make your own' smoking
articles
according to the invention are envisaged wherein such smoking articles
typically use
components commercially available for use in the making of smoking articles
and/or
commercially available accessories for use in conjunction with smoking
articles.
Typical smoke producing substances comprise dried plant matter, for example
tobacco.
Generally the smoke producing substance takes the form of an amorphous
mass or a rod. The smoke producing substance is housed within the smoking
article,
typically within an area towards the distal end of the smoking article. This
area
generally extends along the direction of a longitudinal axis of the smoking
article.
When the smoke producing substance takes the form of a rod, the rod of smoke
producing substance is optionally hollow.
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
3
The smoking article preferably comprises a filter and generally such a filter
is
situated at the smoking article's proximal end. Preferably the filter is
within or covering
the proximal end of any area containing the smoke producing substance such
that, in
use, smoke from the smoke producing substance is filtered prior to delivery to
a
smoker.
The at least one channel of the smoking article is typically substantially
parallel
to the direction of longitudinal extension of the area of the smoking article
containing
the smoke producing substance. The at least one channel is however distinct
from
any such area.
An airflow path along the at least one channel is defined from at least one
vent
hole, typically positioned on an outside face of the smoking article, through
the
channel to the proximal end of the smoking article.
In the case of the smoking article being a cigarette, at least one vent hole
is
typically positioned in the tipping paper of the cigarette.
Generally the cross-section of the at least one channel is between 0.1 and
50% of the cross-section of the smoking article, preferably between 0.1 and
30% and
more preferably between 5 and 20%. As the cross-section of the at least one
channel
is reduced, the air velocity through the channel increases, thus enhancing the
entrainment of the smoke supplement composition into the airflow and hence to
the
smoker. Some formulations of a smoke supplement composition (eg those
comprising
glycerol) may require some heat to aid their transfer into the airstream, and
this may
be accomplished by providing the smoke producing substance as a hollow rod,
and/or
providing a filter having a high pressure drop core, such that the heated
smoke stream
passes in close proximity to the smoke supplement composition which is at the
perimeter of the filter.
The entrainment of the smoke supplement composition into the airflow can
also be improved by increasing channel length, for example by using channels
that
spiral around the smoking article. A further option is to increase convolution
of the
airflow path, and/or to introduce turbulence into the airflow path, for
example by
introducing kinks or baffles into the channels.
The at least one channel of the present invention is typically defined as a
generally concave cavity within a body, wherein the body is comprised within
the
smoking article. In this case the at least one channel is generally formed by
pressing
a heated rod into the body. Alternatively the at least one channel is defined
by a
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
4
corrugated wrapping substance being placed around a body comprised within the
smoking article.
The airflow path may additionally comprise a cavity which, in use, stores the
smoke supplement composition. Alternatively or additionally, the smoke
supplement
composition is stored within the at least one channel. Typically the smoke
supplement composition is placed into the cavity/channel by any known means
either
before, after or during manufacture, such as by injection, pasting, printing
or
depositing.
Typically the smoke supplement composition comprises nicotine or a nicotine
derivative, and optionally it further comprises one or more substances
selected from
a flavourant, a pharmacologically active agent or a smoke modifier.
Pharmalogically active agents include for example antioxidants such as vitamin
C or E, which act to reduce the impact of free radicals within the smoke.
Smoke
modifiers act to reduce the level of undesirable compounds in the smoke,
preferably
by acting on the smoke after its exit from the smoking article but before its
absorption
into the body of the smoker. The level of undesirable components can be
reduced by
chemical reaction of the undesirable component (eg radicals) with the smoke
modifier
(eg an antioxidant) to deactivate the undesirable component, or by reaction of
the
undesirable component (eg radicals) with another component to deactivate the
undesirable component wherein this reaction is catalysed by a smoke modifier
(eg an
iron catalyst). Alternatively, the undesirable component can be adsorbed into
or
amalgamated with a smoke modifier matrix (eg a matrix of fine carbon
granules).
Such absorption/amalgamation can reduce the availability of the undesirable
component and/or alter the way the undesirable component is deposited within
the
airways of the smoker (eg if particles of undesirable component are made
sufficiently
large, these particles will be non-respirable).
Any of the one or more substances, and/or any nicotine or nicotine derivative,
can be encapsulated or micro encapsulated, typically prior to being introduced
into the
smoke supplement composition. Suitable encapsulation or micro encapsulation
materials include starch, gum acacia, glycerol, gelatine, albumin or
cyclodextrin.
Encapsulation or micro encapsulation can be used as a method to contain
volatile
compounds.
The smoke supplement composition can further comprise a substrate material
such as a web or film, or such as solid particles for example cyclodextrin.
Any of the
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
above mentioned nicotine/nicotine derivatives and/or one or more substances
(such
as flavourant, pharmacologically active agents or smoke modifiers), all of
which can
optionally be encapsulated as described above, can be comprised within or on
the
substrate material. Optionally the substrate material becomes entrained in the
5 ventilation air.
The vent holes and/or proximal ends of the grooves of the smokingarticle are
optionally removably sealed such that during storage any volatile smoke
supplement
composition cannot migrate out of the channels and onto other parts of .the
smoking
article, or onto any filter or packaging.
Suitable removable seals include a removable sleeve for the smoking article,
for example a sleeve that slides over the proximal end of the article. Such a
sleeve
could be made from a polymer such as cellophane. Alternatively, a "tear tape"
for the
vent holes and/or the proximal ends of the channels can be incorporated,
wherein this
"tear tape" can be made from any suitable polymer such as cellophane.
In a similar manner, it is preferable that the channels comprise an
impermeable
barrier such that, in use, the smoke supplement composition does not migrate
out of
the channels in any way other than along the airflow path during smoking.
Examples of the present invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 shows the main design aspects of a conventional cigarette;
Figure 2 shows a conventional cigarette with a compound filter containing an
adsorbent;
Figure 3 shows the main airflow paths of a conventional cigarette with a
compound filter;
Figure 4 shows the main airflow paths within a cigarette with a parallel
delivery
system according to the present invention;
Figure 5 shows a filter plug with channels arranged to enable parallel
delivery
according to the present invention;
Figure 6 shows a filter plug with alternative channels arranged to enable
parallel delivery according to the present invention;
Figure 7 shows a cross-section of a filter plug with channels to enable
parallel
delivery according to the present invention;
Figure 8 shows a cigarette according to the present invention comprising a
cavity in which to store smoke supplement composition;
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
6
Figure 9 shows a perspective view of the filter of Figure 8;
Figure 10 shows a cigarette according to the present invention comprising a
hollow tobacco rod; and
Figure 11 shows a cross-section of a cigarette according to the present
invention, wherein the cigarette uses corrugated outer plug wrap arranged to
form
channels.
Looking first at Figure 1, this shows the main design aspects of a
conventional
cigarette 10. The cigarette 10 has a proximal end 11, and at this proximal end
11
there is provided a cylindrical cellulose acetate filter 12. This filter is
wrapped with a
porous plug wrap 13, and is then wrapped with a tipping paper 14. A tipping
paper 14
comprises vent holes 15 which form a ring around the cylindrical filter 12.
Adjoining
the filter 12 at its distal end is a tobacco rod 16. This tobacco rod 16 is
wrapped with
cigarette paper 17.
Looking now at Figure 2, this shows a conventional cigarette with a compound
filter containing an adsorbent. The compound filter comprises a cellulose
acetate
segment 22 at the cigarette's proximal end 11 and an adsorbent containing
segment
22' adjoining the distal end of the cellulose acetate segment 22. In all other
respects
the cigarette is as depicted in Figure 1.
Figure 3 shows the main air flow paths of a conventional cigarette as depicted
in Figure 2. In detail, when the cigarette of Figure 2 is smoked, air is drawn
through
the tobacco rod 16 and through the adsorbent containing filter segment 22' and
into
the cellulose acetate filter segment 22. At this point extra air is drawn
through the vent
holes 15 and into the cellulose acetate filter segment 22. This air mixes with
the air
from the adsorbent containing filter segment 22' and all of the air is drawn
out of the
proximal end 11 of the cigarette by the smoker.
Figure 4 shows the main airflow paths within a cigarette with a parallel
delivery
system according to the present invention. In detail, air is drawn through the
tobacco
rod 16 and subsequently through the adsorbent containing filter segment 22'
and into
the cellulose acetate filter segment 22 as already described with regard to
Figure 3.
This air is further drawn out of the proximal end of the cigarette 11 by the
smoker. In
contrast to Figure 3, however, extra air entering via the vent holes 15 is
drawn along
the channels 41 containing smoke supplement composition 42. This extra air
does
not mix with the air from the tobacco rod 16 but instead is confined to the
channels 41
and is drawn out of the proximal end of the cigarette 11 by the smoker.
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
7
Figure 5 shows a filter plug with channels to enable parallel delivery
according
to the present invention. As can be seen, substantially straight, parallel
channels 41
are formed in the cellulose acetate filter segment 22. The distal ends of the
channels
41 align with vent holes 15 (not shown).
Figure 6 shows a filter plug with alternative channels to enable parallel
delivery
according to the present invention. In contrast to Figure 5, the channels 41
are
arranged so as to extend substantially longitudinally whilst also exhibiting
radial
progression around the axis of the filter segment 22. This arrangement
increases the
length of the channels 41 and can therefore increase the capability of the
cigarette to
deliver smoke supplement composition.
Figure 7 shows a cross-section of a filter plug with channels arranged to
enable parallel delivery according to the present invention. As can be seen,
the
channels 41 are formed from concave depressions within the filter 22.
Figure 8 shows a cigarette according to the present invention comprising a
cavity 81 in which to store smoke supplement composition. In detail, air is
drawn
through the tobacco rod 16 and subsequently through the adsorbent containing
filter
segment 22' and into the cellulose acetate filter segment 22 as already
described with
regard to Figure 3. This air is further drawn out of the proximal end of the
cigarette
11 by the smoker. In a similar manner to Figure 4, extra air is drawn in
through the
vent holes 15 and passes over smoke supplement composition 42 which is
contained
within a cavity 81. This air then passes along the channels 41 and is drawn
out of the
proximal end of the cigarette 11 by the smoker.
Figure 9 shows a perspective view of the filter of Figure 8. As can be seen,
the
cellulose acetate filter 22 comprises a cavity 81, in airflow connection with
channels
41, which extend to the proximal end of the cigarette 11. The cavity 81 aligns
with the
vent holes 15 (not shown).
Figure 10 shows a cigarette according to the present invention comprising a
hollow tobacco rod. In detail, air is drawn through the tobacco rod 16 and
into the
hollow core of the rod 101. This air then passes through the adsorbent
containing
filter segment 22' and into the filter segment 102. This filter segment 102
comprises
a high pressure drop core 103, and the airflow from the adsorbent containing
filter
segment 22' passes between the high pressure drop core 103 and the channels
41,
and is subsequently drawn out of the proximal end of the cigarette 11 by the
smoker.
As described with reaard to Figure 4, the extra air entering via the vent
holes 15 is
CA 02632975 2008-06-11
WO 2007/068309 PCT/EP2006/010365
8
drawn along the channels 41 containing the smoke supplement composition 42.
This
extra air does not mix with the air from the tobacco rod 16 but instead is
confined to
the channels 41 and is drawn out of the proximal end of the cigarette 11 by
the
smoker.
Figure 11 shows a cross-section of a cigarette which uses corrugated outer
plug wrap 112 arranged to form channels. In detail, the channels 111 are
formed by
placing corrugated outer plug wrap 112 around the outside of the cellulose
filter 22.
The corrugated outer plug wrap 112 is separated from the filter 22 by inner
plug wrap
113, and the channels 111 formed by the corrugated outer plug wrap 112 are
sealed
by wrapping tipping paper 14 around the corrugated outer plug wrap 12. The
grooves
extend only part way down the filter and do not come into contact with the
tobacco rod
(not shown).
