[0001] The present invention relates to a ventilated smoking article incorporating a filter
wrapper with a sorbent.
[0002] Filter cigarettes typically comprise a rod of tobacco cut filler surrounded by a
paper wrapper and a cylindrical filter aligned in end-to-end relationship with the
wrapped tobacco rod, with the filter attached to the tobacco rod by tipping paper.
In conventional filter cigarettes, the filter may consist of a plug of cellulose acetate
tow wrapped in porous plug wrap.
[0003] It is common to provide a ventilation zone in a smoking article, typically in the
form of perforations provided in the tipping paper or the plug wrap, or both. The
ventilation zone allows air to enter the filter during smoking and the air dilutes
the mainstream smoke coming through the filter from the burning tobacco rod, thereby
reducing the levels of smoke constituents delivered to the consumer.
[0004] The ventilation zone typically includes perforations provided at one or more positions
along the filter of the smoking article and some of the perforations can be inadvertently
blocked during smoking, for example, by the lips or fingers of the consumer. Air is
thereby prevented from entering the filter and the level of dilution of the mainstream
smoke decreases.
[0005] In addition to the inclusion of a ventilation zone, it is also known to provide a
sorbent material such as activated carbon within the filter of a smoking article as
an additional means to reduce the level of certain smoke constituents. However, sorbent
materials may adversely affect the taste of the mainstream smoke in a way that is
unfavourable to some consumers.
[0006] It would be desirable to provide a novel filter arrangement for a smoking article
that substantially maintains the delivery level of certain smoke constituents whether
the ventilation zone is open or blocked, so that inadvertent covering of the ventilation
zone does not significantly impact smoke constituent delivery. It would further be
desirable if such a filter arrangement could be readily manufactured using existing
apparatus and techniques.
[0007] WO 2009/098462 A1 discloses a tobacco smoke filter or filter element comprising a longitudinally extending
core of tobacco smoke filtering material having fully enclosed therewithin at least
one pocket of a first additive; and a wrapper engaged around the core, the wrapper
having a second additive adhered to one or more portion(s) of the radially inner face
thereof with said wrapper being free of additive around its circumference at one end.
The wrapper including a sorbent material. Ventilation is provided in one or two regions.
[0008] According to the invention there is provided a smoking article comprising: a tobacco
rod; a filter connected to the tobacco rod and comprising one or more filter segments
circumscribed by a filter wrapper including a layer of a sorbent material applied
over an area of a surface of the filter wrapper. The filter includes a ventilation
zone provided upstream of the sorbent material. The result of this arrangement is
that the level of mainstream gas phase smoke constituents delivered during smoking
of the smoking article with the ventilation zone open is within up to 20% of the level
of mainstream gas phase smoke constituents delivered during smoking of the smoking
article with the ventilation zone blocked.
[0009] The ventilation zone refers to the arrangement of perforations or holes that are
provided on the filter to allow ventilation of the filter and dilution of the mainstream
smoke during smoking, through the ingress of air through the holes into the filter.
[0010] The ventilation zone is 'open' when it is fully uncovered and air is free to enter
the filter during smoking. The ventilation zone is 'blocked' when it is covered or
closed so that air is prevented from entering the filter through the ventilation zone.
With the present invention, the level of gas phase mainstream smoke constituents delivered
during smoking of the smoking article when the ventilation zone is blocked is within
up to 40% of the level of the same mainstream gas phase smoke constituents delivered
during smoking with the ventilation zone open. Preferably, the level of gas phase
smoke constituents delivered with the ventilation zone blocked is within up to 30%
of the level delivered with the ventilation zone open, more preferably within up to
20% and most preferably within up to 10%.
[0011] In the context of the present invention, the term 'smoke constituents' is intended
to refer to the gas phase constituents in the mainstream smoke. In particular, the
smoke constituents referred to herein are gas phase carbonyl compounds, including
aldehyde and ketone compounds. For example, the gas phase constituents may include
one or more of formaldehyde, acetaldehyde, acetone and acrolein.
[0012] For the purposes of the present invention, the level of mainstream gas phase smoke
constituents delivered during smoking of a smoking article according to the invention
with the ventilation zone open may be determined by smoking the smoking article under
ISO conditions (35ml puffs lasting 2 seconds each, every 60 seconds). In the ISO test
method, the smoking article is smoked with the ventilation zone fully uncovered. For
the purposes of the present invention, the level of mainstream gas phase smoke constituents
is normalised to nicotine delivery, so that the level is expressed per mg of nicotine.
[0013] The level of mainstream gas phase smoke constituents delivered during smoking of
a smoking article according to the present invention with the ventilation zone blocked
may be determined by smoking the smoking article in a Health Canada test method (55ml
puffs lasting 2 seconds each, every 30 seconds). In the Health Canada test method,
the tipping paper is covered by an air impermeable film or tape so that air cannot
enter the filter through the ventilation zone and the dilution of the mainstream smoke
is approximately 0%. As above, for the purposes of the present invention, the level
of mainstream smoke constituents is normalised to nicotine delivery, so that the level
is expressed per mg of nicotine.
[0014] The level of gas phase smoke constituents in the mainstream smoke is determined as
an average for a sample of 20 smoking articles with the ventilation zone open and
20 smoking articles with the ventilation zone blocked. The level of smoke constituents
is measured as the aggregate amount of carbonyl compounds.
[0015] The present invention provides an effective way of maintaining a relatively constant
delivery of gas phase smoke constituents in a ventilated smoking article, regardless
of whether the ventilation zone is open or blocked.
[0016] In the present invention, the sorbent material is positioned within the filter of
smoking articles such that under normal smoking conditions with the ventilation zone
open, the dilution of the mainstream smoke by air entering the filter through the
ventilation zone will be the main mechanism by which the level of smoke constituents
in the mainstream smoke is reduced. The ventilation air will provide an air cushion
that will isolate much of the mainstream smoke from the sorbent. As such, the sorbent
will have a minimal effect on the level of gas phase smoke constituents and the flavour
of the mainstream smoke when the ventilation zone is open.
[0017] In contrast, when the ventilation zone is fully blocked and air is prevented from
entering the filter and diluting the mainstream smoke, the flow of the mainstream
smoke through the filter changes so that the smoke passes over the sorbent and certain
gas phase smoke constituents are adsorbed or adsorbed by the sorbent. In this case,
the sorption of smoke constituents will be the main mechanism by which the level of
smoke constituents in the mainstream smoke is reduced.
[0018] In some cases, when the ventilation zone is partly blocked, the reduction of smoke
constituents in the mainstream smoke will be achieved both through the dilution of
the mainstream smoke and by the sorbent. The arrangement of the sorbent and ventilation
zone is such that there is a balance between the reduction of gas phase smoke constituents
by dilution and the reduction of the same gas phase smoke constituents by the sorbent,
wherein the balance will automatically shift depending on the degree to which the
ventilation zone is blocked. If the level of dilution decreases as a result of blocking
of the ventilation zone, the sorption of smoke constituents by the sorbent material
will increase to compensate for the lower dilution. The total level of smoke constituents
can therefore be maintained with as little variation as possible, irrespective of
whether the ventilation zone is open, partially blocked, or fully blocked.
[0019] The balance between the level of dilution of the mainstream smoke achieved by the
ventilation zone and the sorption of mainstream smoke constituents by the sorbent
at the surface of the filter wrapper can be controlled by adjusting parameters of
the filter, including but not limited to the positioning and distribution of the ventilation
zone, the level of dilution achieved by the ventilation zone, and the positioning,
distribution and amount of sorbent provided, as described in more detail below. For
example, the amount and position of the ventilation zone and the amount and position
of the sorbent can be adjusted such that the delivery of gas phase smoke constituents
is the same whether the ventilation zone is open or blocked.
[0020] In the filters of smoking articles according to the invention, the ventilation zone
may be provided upstream of most or all of the sorbent material. With this arrangement,
the flow of the mainstream smoke within the filter changes depending on how much air
is drawn through the filter from the ventilation zone. With the ventilation zone open,
the ventilated air is typically drawn through the filter on the outside of the filter
material, constraining the flow of the mainstream smoke towards the centre of the
filter. The air drawn through the ventilation zone therefore provides an outer, concentric
layer which effectively separates and shields the mainstream smoke from the sorbent
that is included in the filter wrapper. In this way, the mainstream smoke does not
significantly come into contact with the sorbent. During normal smoking of the smoking
article, the sorbent will therefore have a minimal effect on the mainstream smoke.
[0021] The ventilation is 'upstream' of the sorbent material, meaning that the ventilation
is provided further from the mouth end of the smoking article than the sorbent. During
smoking, the mainstream smoke is drawn through the smoking article from an upstream
end, closest to the burning end of the tobacco rod, to a downstream end, at the mouth
end of the filter. The mainstream smoke will therefore pass the ventilation zone first,
before reaching the sorbent in the filter wrapper.
[0022] Preferably, the ventilation zone is in the form of one or more rows of perforations
extending circumferentially around the filter. In certain embodiments, a plurality
of rows of perforations may be provided at spaced apart locations along the filter,
for example at least 5mm from one another, or at least 10mm from one another. This
arrangement means that air is admitted into the filter at different positions during
smoking and may help to maintain a consistent layer of air between the mainstream
smoke and the sorbent along the full length of the sorbent. In such a case, the most
upstream ventilation zone may be upstream of all or most of the sorbent.
[0023] When the ventilation zone is blocked, the volume of air entering the filter will
be reduced and in the case where the ventilation zone is fully blocked, substantially
no air will enter the filter. In the absence of the layer of air towards the outside
of the filter, the mainstream smoke will no longer be confined to the central portion
of the filter and the smoke flowing through the outside of the filter will come into
contact with the sorbent included in the filter wrapper. The smaller the volume of
air that is drawn through the filter, the larger the volume of mainstream smoke that
will come into contact with the sorbent and the sorbent will remove an increased amount
of smoke constituents.
[0024] In cases where the ventilation zone is partially blocked, the flow of air and smoke
through the filter will be a combination of the two flow patterns, depending upon
the relative position of the blocked ventilation zone on the filter and the extent
of the blockage. For example, if part of the ventilation zone towards the mouth end
of the filter were blocked but the upstream ventilation zone remained open, the mainstream
smoke may initially be separated from the sorbent by a layer of air at the outside
of the filter but the ventilated air and the smoke may mix towards the mouth end of
the filter, causing more of the smoke to come into contact with the sorbent.
[0025] Preferably, the ventilation zone provides between 10% and 80% dilution of the mainstream
smoke, wherein the 'dilution' refers to the percentage by volume of air that is included
in the smoke delivered to the consumer from the mouth end of the filter with the ventilation
zone completely open. In the present invention, the ventilation zone provides between
30% and 70% dilution of the mainstream smoke, more preferably between 50% and 80%.
The level of ventilation or dilution achieved by the ventilation zone can be determined
using ISO test method 9512:2002.
[0026] The ventilation level can advantageously be adjusted to control the thickness of
the concentric air layer flowing through the outer concentric region of the filter
and separating the mainstream smoke from the sorbent. The thicker the layer of air
at the outside of the filter, the greater will be the effect of the air layer at shielding
the mainstream smoke from the sorbent. This will also reduce the effect the sorbent
will have on the flavour of the smoke delivered to the consumer when smoking with
the ventilation zone open. As another alternative, the level of ventilation through
the ventilation zone may be set and the amount of sorbent may be adjusted so that
the delivery of gas phase smoke constituents is similar whether the ventilation zone
is open or blocked.
[0027] Preferably, the most upstream portion of the ventilation zone is provided between
20 mm and 30 mm from the mouth end of the smoking article. Preferably, the most upstream
portion of the ventilation zone is provided at least 2 mm from the rod end of the
filter, where the filter abuts the rod of tobacco. This positioning of the ventilation
zone away from the mouth end of the filter and towards the rod of tobacco advantageously
increases the available area in which the sorbent may be placed downstream of the
ventilation zone.
[0028] The ventilation zone is provided upstream of all, or substantially all of the sorbent
material. Whilst the ventilation zone is preferably provided upstream of all of the
sorbent material, the skilled person will appreciate that the desired effect of the
present invention can be achieved where the majority of the sorbent is downstream
of the ventilation zone, even if a small proportion is provided at the position of
the ventilation zone, or upstream of the ventilation zone. Preferably, the ventilation
zone is provided upstream of at least 80% of the sorbent.
[0029] The sorbent material may be formed of any suitable adsorbent or absorbent material.
A variety of sorbents for use in smoking articles would be known to the skilled person.
Suitable sorbents include but are not limited to activated carbon, zeolites, sepiolites,
alumina, molecular sieves and combinations thereof. In particularly preferred embodiments,
the sorbent is activated carbon.
[0030] In preferred embodiments, the filter wrapper of smoking articles according to the
invention comprises a layer of sorbent applied over an area of a surface of the filter
wrapper. Preferably, the amount of sorbent in the layer is at least about 20 mg. The
amount of sorbent is preferably up to about 120 mg, more preferably up to about 100
mg, more preferably up to about 60 mg. Particularly preferably, the amount of sorbent
is between about 20 mg and about 120 mg, more preferably between about 40 mg and about
60 mg.
[0031] The sorbent material is preferably provided in the form of a particulate or granular
sorbent, which is preferably applied to a layer of adhesive or binder on the surface
of the filter wrapper. In alternative embodiments, the sorbent may be provided as
a separate layer located at the surface of the filter wrapper. In other alternative
embodiments, the sorbent material may be applied as a separate layer to the outer
surface of a filter segment and the filter wrapper may be wrapped over the sorbent
layer to bring the surface of the filter wrapper into contact with the sorbent.
[0032] In addition or as an alternative to the provision of sorbent material in a layer
at the surface of the filter wrapper, a sorbent material may be incorporated towards
the outside of the filter material itself. For example, where the filter comprises
a plug of fibrous filter material such as cellulose acetate tow, a particulate sorbent
material may be provided in a concentric, outer layer of the filter tow, for example
a concentric, outer layer that is less than 1mm thick. The sorbent may be provided
uniformly in a concentric outer layer of the filter tow, or there may be a concentric
gradient of sorbent within the filter, wherein the proportion of sorbent in the filter
tow increases towards the outside of the filter.
[0033] In addition or as an alternative to the arrangements of sorbent described above,
a sorbent may be incorporated into the sheet material forming the filter wrapper,
for example, the sorbent may be incorporated into a paper material during production
of the material.
[0034] Where the sorbent material is on a surface of the filter wrapper, the sorbent material
preferably covers at least 50% of the outer or inner surface of the filter wrapper,
more preferably at least 60%. The sorbent material may be provided within a single
area, or may be provided in a plurality of areas over the surface of the filter wrapper,
for example, in the form of a pattern applied to the surface of the filter wrapper.
[0035] The sorbent material is preferably provided on the inner surface of the filter wrapper,
wherein the 'inner' surface refers to the radially inner surface of the wrapper, which
is closest to the filter segment. However, in certain alternative embodiments it may
be effective to provide the sorbent on the outer surface of the wrapper in addition
to or as an alternative to sorbent on the inner surface, provided the mainstream smoke
will still be brought into contact with the sorbent during smoking. For example, where
the filter wrapper is highly porous or air permeable, the sorbent may be provided
on either or both of the inner and outer surfaces since the mainstream smoke will
be in contact with both surfaces during smoking.
[0036] In certain preferred embodiments of the present invention, the filter wrapper to
which the sorbent is applied is a plug wrap circumscribing the filter along at least
a part of its length. The sorbent may be applied to an inner layer of plug wrap, the
inner surface of which is in contact with the underlying filter material.
[0037] In some cases, the filter is wrapped with a second layer of plug wrap, for example
a layer of plug wrap that combines the different segments of a multi-component filter.
Alternatively or in addition to the sorbent on the inner layer of plug wrap, sorbent
material may be applied to this second layer of plug wrap, which overlies one or more
inner layers of an air permeable plug wrap. The sorbent material may be applied to
an area of the inner surface of the second layer of plug wrap. Alternatively or in
addition, the sorbent material may be applied to the outer surface of the second layer
of plug wrap, in particular where the second layer of plug wrap is formed of a substantially
air permeable sheet material so that the mainstream smoke will readily permeate through
the second layer of plug wrap to come into contact with the sorbent.
[0038] In other preferred embodiments of the present invention, the filter wrapper to which
the sorbent is applied is a tipping wrapper, such as a tipping paper, circumscribing
the filter and connecting the filter to the tobacco rod. Where the sorbent material
is provided on the tipping wrapper, the material should be applied to the inner surface
of the tipping wrapper so that it is not exposed at the outside of the filter.
[0039] The filter of smoking articles according to the present invention may include a single
filter segment. Alternatively, the filter may comprise two or more filter segments
in axial alignment with each other. The filter segment or segments may take a variety
of forms and suitable filter segments would be known to the skilled person. Where
two or more filter segments are included, the filter segments may be of the same construction
and materials as each other, or may have a different construction, or contain different
filtration material or additives. Preferably, the filter segment or segments are each
formed of a plug of fibrous filtration material, such as cellulose acetate tow or
paper, and wrapped with a plug wrap.
[0040] One or more of the filter segments may include a particulate material. The particulate
material is preferably incorporated in an upstream filter segment, for example, in
a rod end filter segment.
[0041] The particulate material may be dispersed through a plug of fibrous filtration material,
such as cellulose acetate or paper. A filter plasticiser may be applied to the fibrous
filtration material in a conventional manner, by spraying it onto the separated fibres,
preferably before applying the particulate material to the filtration material. Alternatively
or in addition, the filter may include a filter segment with a hollow cavity at least
partially filled with a particulate material. In such cases, the hollow cavity is
preferably provided between two plugs of a filtration material.
[0042] The particulate material incorporated into the filter may include at least one sorbent
material, such as those indicated above for inclusion in the filter wrapper. Where
a sorbent is incorporated within the filter, the amount of sorbent within the filter
should be less than the amount of sorbent included in the filter wrapper so that the
performance characteristics of the filter can be maintained.
[0043] Additionally or as an alternative, the particulate material incorporated into the
filter may include at least one flavourant material. For example, the particulate
material may include particles of a sorbent or cellulosic material loaded with a liquid
flavourant, such as menthol. Alternatively, the particulate material may comprise
particles of plant material. The plant material may be in the form of plant leaf,
as described in
EP-A-1,958,523. For example, the filter segment may include leaf from tobacco, green tea, mint,
such as peppermint or spearmint, laurel, eucalyptus, basil, sage, verbena and tarragon.
The plant material may alternatively be in the form of a seed, root, bark or flower,
such as those typically used as spices.
[0044] Alternatively, one or more of the filter segments may have a liquid flavourant such
as menthol applied directly to the filtration material.
[0045] Preferably, the overall length of smoking articles according to the invention is
between 70 mm and about 128 mm, for example about 84 mm.
[0046] Preferably, the external diameter of smoking articles according to the invention
is between about 5 mm and about 8.5 mm, more preferably about 7.9 mm.
[0047] Preferably, the overall length of the filters of smoking articles according to the
invention is between about 18 mm and about 36 mm, more preferably about 27 mm.
[0048] The smoking articles of the present invention comprise a rod of tobacco material,
which is attached to the filter by a tipping wrapper. The rod of tobacco material
may include cut tobacco taken from one or more types of tobacco leaf, expanded tobacco,
reconstituted tobacco, or combinations thereof.
[0049] The invention will now be further described by way of example only with reference
to the accompanying drawings in which:
Figure 1 shows a perspective view of a smoking article according to the invention,
with the filter unwrapped;
Figure 2 shows a side view of the smoking article of Figure 1, with a schematic representation
of the flow of air and smoke through the filter when the ventilation zone is open;
and
Figure 3 shows a side view of the smoking article of Figure 1, with a schematic representation
of the flow of smoke through the filter when the ventilation zone is fully blocked.
[0050] The filter cigarette 10 shown in Figure 1 comprises a wrapped rod 12 of tobacco cut
filler, which is attached to an axially aligned filter 14. The tobacco rod 12 is wrapped
with a cigarette paper (not shown). The filter 14 comprises a single segment 16, which
is formed of a plug of cellulose acetate tow. The filter segment 16 is wrapped with
a plug wrap 18 which circumscribes the entire length of the filter 14.
[0051] The plug wrap 18 is formed of a sheet of an air permeable paper material and includes
a sorbent layer 20 covering an area corresponding to approximately 50% of the inner
surface of the plug wrap 18. The sorbent layer 20 is formed of a substantially evenly
distributed layer of around 50 mg of particulate activated carbon, which has been
affixed to the inner surface of the plug wrap 18 by a suitable adhesive. In the assembled
filter, the sorbent layer 20 extends circumferentially around the filter segment 16
and is in contact with the outer surface of the filter segment 16.
[0052] The wrapped tobacco rod 12 and the wrapped filter 14 are joined to each other by
an outer tipping wrapper 22, which circumscribes the entire length of the filter 14
and an adjacent portion of the tobacco rod 12, and overlies the plug wrap 16. The
tipping wrapper 22 is formed of a tipping paper which has been provided with ventilation
zone comprising a row of perforations 24 extending circumferentially around the filter
14. The row of perforations 24 is positioned on the filter at the rod end of the filter
segment 16, adjacent the interface between the filter 14 and the tobacco rod 12. The
entire area of the sorbent layer 20 is downstream of the row of perforations 24. With
the perforations open, the ventilation zone provides about 60% dilution of the mainstream
smoke during smoking.
[0053] During normal smoking of the filter cigarette 10, the perforations will be fully
uncovered and as shown schematically in Figure 2, air will be admitted into the filter
14 through the perforations in the tipping wrapper 22. In Figure 2, the air flow is
indicated by the hollow arrows whilst the mainstream smoke flow is indicated by the
shaded arrows. As shown, the air will be drawn along through the filter 14 towards
the mouth end of the filter 14 and will form a concentric air layer 26 around the
outside of the filter segment 16. The mainstream smoke will be drawn from the tobacco
rod and the presence of the air layer 26 forces the mainstream smoke towards the centre
of the filter segment 16 so that the mainstream smoke is separated from the inner
surface of the plug wrap 18 by the air layer 26. This means that during smoking with
the perforations 24 fully open, contact will be limited between the mainstream smoke
and the activated carbon in the sorbent layer 20 on the inner surface of the plug
wrap 18. As such, the presence of the sorbent layer 20 will have a negligible effect
on the levels of the gas phase constituents in the mainstream smoke. The air flowing
into the filter 14 will, however, dilute the mainstream smoke thereby reducing the
level of gas phase constituents in the smoke received by the consumer by around 60%.
[0054] The positioning of the row of perforations 24 upstream of the entire sorbent layer
20 ensures that the mainstream smoke is directed away from the outside of the filter
segment 16 into the centre of the filter before the mainstream smoke reaches the part
of the filter segment at which the sorbent layer 20 starts.
[0055] Figure 3 illustrates the condition where all of the perforations 24 are fully covered
so that no air is admitted to the filter 14 during smoking. Under these conditions,
there is no dilution of the mainstream smoke in the filter and therefore no reduction
of the gas phase constituents as a result of the ventilation zone. As shown schematically
by the shaded arrows in Figure 3, in the absence of the air layer 26 the mainstream
smoke is not constrained to the centre of the filter segment 16 and can be drawn through
the full cross section of the filter segment 16. Unlike in the situation shown in
Figure 2, the mainstream smoke therefore comes into contact with the sorbent layer
20 on the inner surface of the plug wrap 18 as the smoke is drawn through the filter
14. The activated carbon in the sorbent layer 20 adsorbs certain gas phase constituents
from the mainstream smoke and the total level of these constituents in the smoke delivered
to the consumer is therefore reduced.
[0056] The level of the gas phase constituents (carbonyl compounds) in the mainstream smoke
under the conditions shown in Figure 3 is within up to 40% of the level of the same
gas phase constituents as a result of the dilution under the conditions shown in Figure
2.
[0057] In reality, during smoking the consumer is unlikely to fully block all of the perforations
24 in the tipping paper 22 and the conditions illustrated in Figure 3 are therefore
only likely to be brought about during an experimental Health Canada smoking test.
The consumer may, however, inadvertently block some of the perforations 24, for example,
by placing their fingers around the filter in the region of the ventilation zone,
so that air cannot be admitted into the filter 14 through the perforations covered
by the fingers. In this case, the conditions will be between the two examples shown
in Figures 2 and 3, wherein the air layer 26 does not extend all around the filter
14 and the mainstream smoke will flow into contact with the sorbent layer 20 in certain
places.
[0058] Due to the partial blocking of the perforations 24, the volume of air admitted to
the filter 14 will decrease and the dilution of the mainstream smoke will also decrease
so that the reduction in the levels of gas phase constituents as a result of dilution
will be less. However, the contact of the mainstream smoke with the activated carbon
in the sorbent layer 20 will increase the reduction of the gas phase constituents
by the sorbent so that the overall level of the gas phase constituents is still within
up to 40% of the level under the conditions shown in Figures 2 and 3.
[0059] It can therefore be seen that the overall level of gas phase constituents in the
mainstream smoke as a result of the combination of the dilution and the sorbent layer
20 remains relatively consistent whether the perforations 24 are open, partially blocked
or fully blocked.
[0060] Whilst in the example described above and shown in the figures, the sorbent layer
is provided on the inner surface of the plug wrap, it will be appreciated that different
arrangements of the sorbent layer on the plug wrap and/or the tipping wrapper could
be provided with the same effect on the reduction of the gas phase constituents of
the mainstream smoke, as described above.
1. A smoking article comprising:
a tobacco rod (12); and
a filter (14) connected to the tobacco rod (12) and comprising one or more filter
segments (16) circumscribed by a filter wrapper including a layer of a sorbent material
applied over an area of a surface of the filter wrapper, wherein the filter comprises
a ventilation zone provided upstream of the sorbent material, wherein:
the ventilation zone provides between 30% and 70% dilution when the ventilation zone
is fully open;
the ventilation zone is provided upstream of all of the sorbent material; and
the ventilation zone is between 20mm and 30mm from the mouth end of the smoking article,
such that a level of mainstream gas phase smoke constituents when the ventilation
zone is open is within up to 20% of the level of mainstream gas phase smoke constituents
when the ventilation zone is blocked; and
the air drawn through the ventilation zone provides an outer, concentric layer which
separates and shields the mainstream smoke from the sorbent material included in the
filter wrapper
2. A smoking article according to claim 1 wherein the ventilation zone comprises one
or more rows of perforations (24) extending circumferentially around the filter (14).
3. A smoking article according to claim 2 wherein the rows of perforations are spaced
at least 5 mm from each other.
4. A smoking article according to any of claims 1 to 3 wherein the filter wrapper is
a plug wrap (18) or a tipping wrapper (22).
5. A smoking article according to any preceding claim wherein the filter wrapper comprises
a layer of sorbent (20) applied to at least a portion of the inner surface of the
filter wrapper.
6. A smoking article according to any of claims 1 to 4 wherein the filter wrapper is
substantially air permeable and wherein a layer of sorbent (20) is applied to at least
a portion of the outer surface of the filter wrapper.
7. A smoking article according to claim 5 or 6 wherein the filter wrapper comprises between
about 40 mg and about 60 mg of sorbent material.
8. A smoking article according to any preceding claim wherein the sorbent covers at least
60% of one of the inner or outer surfaces of the filter wrapper.
9. A smoking article according to any preceding claim wherein the sorbent comprises particulate
sorbent applied to a layer of adhesive on a surface of the filter wrapper.
10. A smoking article according to any of the preceding claims wherein the sorbent material
comprises a particulate sorbent incorporated into the filter wrapper.
11. A smoking article according to any preceding claim wherein the filter comprises one
or more segments of a fibrous filtration material.
1. Raucherartikel, aufweisend:
einen Tabakstock (12); und
einen Filter (14), der mit dem Tabakstock (12) verbunden ist und ein oder mehrere
Filtersegmente (16) aufweist, die durch eine Filterumhüllung abgegrenzt sind, welche
eine Schicht aus einem Sorbensmaterial einschließt, das über einen Bereich einer Fläche
der Filterumhüllung aufgebracht ist, wobei der Filter eine Belüftungszone aufweist,
die zuströmseitig des Sorbensmaterials vorgesehen ist, wobei
die Belüftungszone zwischen 30 % und 70 % Verdünnung bereitstellt, wenn die Belüftungszone
vollständig geöffnet ist;
die Belüftungszone zuströmseitig des gesamten Sorbensmaterials vorgesehen ist; und
die Belüftungszone sich zwischen 20 mm und 30 mm von dem Mundende des Raucherartikels
befindet,
sodass ein Niveau an Hauptstromgasphasenrauchbestandteilen bei offener Belüftungszone
innerhalb von bis zu 20 % des Niveaus an Hauptstromgasphasenrauchbestandteilen liegt,
wenn die Belüftungszone blockiert ist; und
die durch die Belüftungszone gezogene Luft eine äußere konzentrische Schicht bereitstellt,
die den Hauptstromrauch von dem in der Filterumhüllung eingeschlossenen Sorbensmittel
trennt und abschirmt.
2. Raucherartikel nach Anspruch 1, wobei die Belüftungszone eine oder mehrere Perforationsreihen
(24) aufweist, die sich in Umfangsrichtung um den Filter (14) herum erstrecken.
3. Raucherartikel nach Anspruch 2, wobei die Perforationsreihen einen Abstand von mindestens
5 mm voneinander aufweisen.
4. Raucherartikel nach einem der Ansprüche 1 bis 3, wobei die Filterumhüllung eine Einsatzumhüllung
(18) oder eine Mundstückbelagumhüllung (22) ist.
5. Raucherartikel nach einem der vorstehenden Ansprüche, wobei die Filterumhüllung eine
Sorbensschicht (20) aufweist, die auf mindestens einen Abschnitt der Innenfläche der
Filterumhüllung aufgebracht ist.
6. Raucherartikel nach einem der Ansprüche 1 bis 4, wobei die Filterumhüllung im Wesentlichen
luftdurchlässig ist, und wobei eine Sorbensschicht (20) auf mindestens einen Teil
der Außenfläche der Filterumhüllung aufgebracht ist.
7. Raucherartikel nach Anspruch 5 oder 6, wobei die Filterumhüllung zwischen ungefähr
40 mg und ungefähr 60 mg Sorbensmaterial aufweist.
8. Raucherartikel nach einem der vorstehenden Ansprüche, wobei das Sorbens mindestens
60 % von einer von der Innen- oder der Außenfläche der Filterumhüllung abdeckt.
9. Raucherartikel nach einem der vorstehenden Ansprüche, wobei das Sorbens ein partikelförmiges
Sorbens umfasst, das auf eine Klebstoffschicht auf einer Fläche der Filterumhüllung
aufgebracht ist.
10. Raucherartikel nach einem der vorstehenden Ansprüche, wobei das Sorbensmaterial ein
partikelförmiges Sorbensmittel aufweist, das in die Filterumhüllung integriert ist.
11. Raucherartikel nach einem der vorstehenden Ansprüche, wobei der Filter ein oder mehrere
Segmente aus einem Faserfiltermaterial umfasst.
1. Article à fumer comprenant :
une tige de tabac (12) ; et
un filtre (14) connecté à la tige de tabac (12) et comprenant un ou plusieurs segments
de filtre (16) circonscrits par une enveloppe de filtre incluant une couche d'un matériau
sorbant appliqué sur une zone d'une surface de l'enveloppe de filtre, dans lequel
le filtre comprend une zone de ventilation prévue en amont du matériau sorbant, dans
lequel :
la zone de ventilation fournit une dilution entre 30 % et 70 % lorsque la zone de
ventilation est entièrement ouverte ;
la zone de ventilation est prévue en amont de tout le matériau sorbant ; et
la zone de ventilation se situe entre 20 mm et 30 mm de l'extrémité buccale de l'article
à fumer,
de telle sorte qu'un niveau de constituants de fumée de la phase gazeuse principale
lorsque la zone de ventilation est ouverte soit jusqu'à 20 % du niveau des constituants
de fumée de la phase gazeuse principale lorsque la zone de ventilation est bloquée
; et
l'air aspiré à travers la zone de ventilation fournit une couche extérieure concentrique
qui sépare et protège la fumée principale du matériau sorbant inclus dans l'enveloppe
du filtre.
2. Article à fumer selon la revendication 1, dans lequel la zone de ventilation comprend
une ou plusieurs rangées de perforations (24) s'étendant circonférentiellement autour
du filtre (14).
3. Article à fumer selon la revendication 2, dans lequel les rangées de perforations
sont espacées d'au moins 5 mm l'un de l'autre.
4. Article à fumer selon l'une quelconque des revendications 1 à 3, dans lequel l'enveloppe
de filtre est une enveloppe de bouchon (18) ou une enveloppe de bout-filtre (22).
5. Article à fumer selon l'une quelconque des revendications précédentes, dans lequel
l'enveloppe de filtre comprend une couche de sorbant (20) appliquée à au moins une
partie de la surface intérieure de l'enveloppe de filtre.
6. Article à fumer selon l'une quelconque des revendications 1 à 4, dans lequel l'enveloppe
de filtre est sensiblement perméable à l'air et dans laquelle une couche de sorbant
(20) est appliquée à au moins une partie de la surface extérieure de l'enveloppe de
filtre.
7. Article à fumer selon la revendication 5 ou 6, dans lequel l'enveloppe de filtre comprend
entre environ 40 mg et environ 60 mg de matériau absorbant.
8. Article à fumer selon l'une quelconque des revendications précédentes, dans lequel
le sorbant couvre au moins 60 % de l'une des surfaces intérieure ou extérieure de
l'enveloppe de filtre.
9. Article à fumer selon l'une quelconque des revendications précédentes, dans lequel
le sorbant comprend un sorbant particulaire appliqué à une couche d'adhésif sur une
surface de l'enveloppe de filtre.
10. Article à fumer selon l'une quelconque des revendications précédentes, dans lequel
le matériau sorbant comprend un sorbant particulaire incorporé dans l'enveloppe de
filtre.
11. Article à fumer selon l'une quelconque des revendications précédentes, dans lequel
le filtre comprend un ou plusieurs segments d'un matériau de filtration fibreux.