Note: Descriptions are shown in the official language in which they were submitted.
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 1 -
Smoking Articles
Technical Field
The present invention relates to smoking articles and, in particular, to
smoking articles
which reduce the machine measured yields of specific constituents or groups of
constituents in mainstream smoke.
Background
Conventionally, smoking articles such as cigarettes comprise a tobacco rod in
the form
of a cylinder of tobacco or tobacco-based smokeable material wrapped in a
paper
wrapper, which may be provided with a filter unit. In its basic form, the
filter unit is a
io cylindrical element formed from filtration material such as cellulose
acetate tow,
optionally including features to modify the smoke flow and filter function,
such as
recesses and gaps, and additives such as particulate carbon. The tow may be
wrapped
in a layer of plug wrap which helps maintain the cylindrical shape and
structure of the
filtration material. The filter unit is joined to the tobacco rod using a
tipping paper,
which is an outer paper layer wrapped around the filter unit and overlapping
the join
between the filter unit and tobacco rod. The tipping paper is glued in place.
Tobacco smoke is a complex, dynamic mixture of more than 5000 identified
constituents of which approximately 150 have been documented as being
undesirable.
The constituents are present in the mainstream smoke (MS) which is inhaled by
a
smoker and are also released between puffs as constituents of sidestream smoke
(SS).
In 2001 the Institute of Medicine (IOM) reported that, since smoking related
diseases
were dose-related, and because epidemiologic studies show reduction in the
risk of
smoking related diseases following cessation, it might be possible to reduce
smoking
related risks by developing potential reduced-exposure products (PREPs). These
they
defined as: (1) products that result in the substantial reduction in exposure
to one or
more tobacco toxicants; and (2) if a risk reduction claim is made, products
that can
reasonably be expected to reduce the risk of one or more specific diseases or
other
adverse health effects (Stratton et al, 2001). To date, no combustible
cigarette product
has been shown to meet the general requirements outlined by the IOM.
There is, therefore, a challenge to provide a smoking article which shows
significant
reduction in emissions of all MS constituents considered to be undesirable.
However,
individual measures to reduce certain constituents will frequently give rise
to no
CA 02868222 2016-05-13
31511-37
- 2 -
reduction in other constituents and, in some cases, even an increase in the
levels of others.
In addition, it is also important to produce a product which is acceptable to
the consumer.
Much of the sensory impact of a conventional smoking article is based upon the
constituents
of the MS as well as other factors, such as pressure drop and number of puffs.
It has been
found that some measures taken to reduce certain MS constituents have the
potential to
provide the smoker with an unsatisfactory smoking experience.
Summary of the Invention
According to an aspect of the present invention, there is provided a smoking
article
comprising a rod of smokeable material and a filter attached to one end of the
rod, said filter
comprising at least two sections and being wrapped in a porous plug wrap,
wherein a first
tipping wrapper overlies the join between the rod of smokeable material and
the filter to attach
the filter to the rod, and at least one additional tipping wrapper is provided
around the filter,
spaced from and separate to the first tipping wrapper to form a gap between
the first and at
least one additional tipping wrapper such that a portion of the porous plug
wrap is exposed
between the first and at least one additional tipping wrapper, this gap being
a section of the
filter which is surrounded only by the porous plug wrap, and wherein the
tipping wrappers are
less porous than the plug wrap.
In accordance with embodiments of the invention, a smoking article is provided
comprising a
rod of smokeable material and a filter attached to one end of the rod, said
filter comprising at
least three sections and being wrapped in a porous plug wrap, wherein a first
tipping wrapper
overlies the join between the rod of smokeable material and the filter, and at
least one
additional tipping wrapper is provided around the filter, spaced from and
separate to the first
tipping wrapper such that a portion of the porous plug wrap is exposed between
the first and at
least one additional tipping wrapper, and wherein the tipping wrappers are
less porous than
the plug wrap.
CA 02868222 2016-05-13
31511-37
- 2a -
In some embodiments, at least one filter section comprises a fibrous filter
material. At least
one filter section may comprise a porous absorbent material. At least one
filter section may
comprise an ion exchange resin.
In certain embodiments, the porous adsorbent material which may be included in
at least one
filter section is a porous carbon with an engineered porous structure. The
filter section may
include from about 20 mg to about 80 mg of the porous adsorbent material.
In certain embodiments, the ion exchange resin which may be included in at
least one filter
section has a surface activated amine. The filter section may include from
about 5 mg to
about 40 mg of the ion exchange resin.
In some embodiments, the filter comprises a mouth end section comprising a
fibrous filter
material, a section comprising an ion exchange resin and a section adjacent
the rod of
smokeable material comprising porous adsorbent material.
In some embodiments the filter is longer than the filter in a conventional
cigarette, having a
length from about 30 mm to about 40 mm, preferably about 37 mm.
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 3 -
In some embodiments the smoking article has an overall length, including the
filter and
the rod of smokeable material, of about 83 mm.
In some embodiments the smoking article has a smaller circumference than that
of a
conventional cigarette, having a circumference of about 21 111111
In some embodiments, the gap between the first and at least one additional
tipping
wrapper is about 10 mm wide.
In some embodiments, the smoking article further includes ventilation holes
formed in
a tipping wrapper and/or in the body of the filter.
In some embodiments, the rod of smokeable material comprises one or more of:
(a) a tobacco treated to produce reduced levels of nitrogenous compounds;
(b) a tobacco treated to remove polyphenols and/or peptides;
(c) a tobacco substitute sheet comprising a non-combustible inorganic filler,
a
binder and an aerosol generating means.
In addition, the smokeable material may further comprise lamina tobacco and/or
dry
ice expanded tobacco (DIET).
Furthermore, in some embodiments, the smokeable material further comprises
glycerol. The smokeable material may also or alternatively comprise at least
one
flavour.
In some embodiments, the smokeable material of the smoking article comprises a
blend treated tobacco, tobacco substitute sheet, DIET, lamina tobacco,
glycerol and a
top flavour.
Brief Description of Figures
Embodiments of the invention will now be described, by way of non-limiting
example
only, with reference to the accompanying drawings, in which:
Figure 1 is a schematic illustration of a smoking article according to an
embodiment of
the invention;
Figure 2 is an exploded view illustrating the interior structure of the filter
of Figure 1 in
more detail;
Figure 3 is a schematic illustration of a longitudinal cross-sectional view of
a smoking
article according to an alternative embodiment of the invention;
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 4 -
Figure 4 shows a summary of the process by which high activity polymer-derived
carbon is prepared; and
Figure 5 shows vent flow measurements for varying ventilation systems.
Detailed Description
The present invention relates to smoking articles including a filter design
which
provides an enhanced ventilation system to provide a smoking article with
increased
toxicant reductions whilst retaining consumer acceptability.
According to some embodiments, toxicant reductions can be further enhanced by
combining the filter with bespoke tobacco blends and/or bespoke adsorbent
filter
io additives. In addition, an optional new overall smoking article format
can assist in
balancing the effects of the filter design and other toxicant reduction
measures to
enhance the consumer acceptability of the smoking article.
In a standard or conventional cigarette the filter and tobacco rod are joined
by a tipping
wrapper which covers the entire length of the filter and the adjacent end of
the tobacco
rod. Where ventilation is provided, this tends to be in the form of holes or
channels
formed in the tipping paper, to allow ambient air to be drawn into the filter
and to
dilute the MS.
In embodiments of the present invention, the tipping wrapper does not cover
the entire
filter. Rather, the tipping paper is split and/or comprises two or more
strips. A first
tipping wrapper covers the join between the filter and rod of smokeable
material, for
example to attach the filter to the rod. At least one additional tipping
wrapper
surrounds another part of the filter, spaced from and separate to the first
tipping
wrapper such that a gap is formed between the first and at least one
additional tipping
wrapper. This gap exposes an area of the filter which is surrounded with a
material
which is more porous than the tipping wrappers. This results in a section of
the filter
which is surrounded only by a porous (plug wrap) paper, allowing increased
diffusion
of gases into and out of the filter area. For example, gases such as CO
(carbon
monoxide) and NO (nitric oxide) may diffuse out of the filter from this filter
area. This
so-called 'split tipping' can also improve vent level control at higher flow
rates.
Referring now to Figures 1 and 2, a smoking article lo according to an
embodiment of
the invention is shown comprising a rod of smokeable material 11 and a filter
12. In one
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 5 -
embodiment, the smokeable material rod 11 comprises a cylinder of smokeable
tobacco
or tobacco-based material contained within a paper sleeve.
The rod of smokeable material 11 is attached to a filter 12. In the
illustrated
embodiment, a first tipping wrapper 14 is positioned to overlay the join
between the rod
of smokeable material 11 and the filter. This tipping wrapper 14 helps to
attach the rod
11 to the filter 12. An additional tipping wrapper 15 surrounds the filter at
the mouth
end 13 of the filter. The tipping wrappers 14, 15 are positioned spaced from
and separate
to one another to provide a gap 16 between them. This gap 16 is a section of
the filter
which is not surrounded by a tipping wrapper. In the illustrated embodiment,
this
/o section of the filter at the gap 16 is surrounded by an exposed porous
plug wrap.
The structure of the filter 12 is illustrated in more detail in the exploded
view of Figure
2. The filter comprises three separate filter sections 21a, 21b, 21C. Each
individual filter
section 21a, 21b, 21C is preferably different. In order that each individual
filter section
21, 21b, 21C retains the desired structure, they may optionally be each
individually
/5 wrapped in an individual inner plug wrap 22a, 22b, 22C.
Once positioned together end-to-end, the three individually wrapped filter
sections 21a,
21b, 21C are then wrapped together with a single outer plug wrap 23 which
holds them
together as a single unit. The outer plug wrap 23 is made of a porous
material, and at
least some of the individual inner plug wraps 22a, 22b, 22C may also be
porous.
20 The filter 12 is attached to the tobacco rod 11 by the first tipping
wrapper 14 which is
wrapped around the tobacco rod 11 and the filter 12 so that it overlies the
join
therebetween. The tipping wrapper is glued in place.
A second, separate tipping wrapper 15 is wrapped around the mouth end 13 of
the filter
12 distal to the tobacco rod 11, and is spaced from the first tipping wrapper
14 to leave a
25 gap 16 therebetween. The outer plug wrap 23 is exposed in the gap 16 to
define a
ventilation area in the filter section of the smoking article 10. The porosity
of this
section of the filter will be determined by the porosity of the outer plug
wrap 23 and any
inner plug wrap surrounding the filter in that area. The tipping wrappers
preferably
provide areas of reduced porosity compared to the porosity of the paper
surrounding
30 the section of the filter aligned with the gap 16 between the tipping
wrappers 14, 15.
In the embodiment of the invention illustrated in Figures 1 and 2, the filter
12 is
described as comprising three separate sections 21a, 21b, 21C. However, it
will be
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 6 -
appreciated that more than three filter sections may be provided within the
scope of the
invention. Furthermore, the invention is not intended to be limited to each
individual
filter section 21a, 21b, 21C being first wrapped in its own individual plug
wrap 22a, 22b,
22C, and instead, the outer plug wrap 23 may serve to hold all of the filter
sections
together and in their preferred form, which may be cylindrical.
In the embodiment shown in Figure 2, the three filter sections 21a, 21b, 21C
are not of
equal size. In the illustrated embodiment, the mouth end section 21C is
shorter than
the middle section 21b, which in turn is shorter than the section 2ia adjacent
the rod of
smokeable material. In a particular embodiment, the mouth end section 21C is 7
mm in
/o length, the middle section 21b is 10 mm in length and the section 2ia
adjacent the rod
of smokeable material is 20 mm in length.
The first and second tipping wrappers 14, 15 are sized and positioned to
expose part of
the section 2ia adjacent the rod of smokeable material. The second tipping
wrapper 15
at the mouth end of the filter is wider than the first tipping wrapper 14. In
the
/5 particular embodiment illustrated in Figure 2, the first tipping wrapper
covers an area
11 mm wide, overlying the end of the rod of smokeable material and part of the
adjacent
filter section 21a. Specifically, the first tipping wrapper 14 may overlay 5
mm of the rod
of smokeable material and 6 mm of the adjacent filter section 21a. The gap
between the
first tipping wrapper 14 and the second tipping wrapper 15 in the illustrated
20 embodiment is lo mm. Again in the embodiment illustrated in Figure 2,
the second
tipping wrapper covers an area 21 mm wide at the mouth end of the filter 12,
overlying
all of the mouth end filter section 21C, all of the central filter section 21b
and a portion
(4- mm) of the filter section 2ia adjacent the rod of smokeable material.
Thus, the gap
16 between the first and second tipping wrappers 14, 15 is aligned with a
portion of the
25 filter section 22a adjacent the rod of smokeable material 11.
Variations are possible from the above described smoking article lo within the
scope of
the invention. For example, more than two separate tipping wrappers may be
provided
circumscribing the filter and/or rod of smokeable material and they may be
positioned
so as to provide two or more gaps. The size (width) of the wrappers and their
positions
30 may vary to provide gaps of varying width and at varying positions. In
addition, the
number and sizes of the filter sections may also vary.
Figure 3 shows an alternative embodiment of the smoking article, wherein the
filter 112
further includes ventilation holes 131. The smoking article 110 comprises the
same
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 7 -
components as the smoking article 10 illustrated in Figure 2, with the
exception that it
includes ventilation holes 131.
The purpose of ventilation holes is to allow air to enter the filter when a
smoker draws
on the smoking article. The air mixes with and dilutes the mainstream smoke
and other
components drawn through the filter from the ignited smokeable material. There
are a
range of techniques currently used for making ventilation holes. The tipping
wrapper
may be pre-perforated before wrapping by a mechanical or electrostatic
perforating
device or by a laser beam. Alternatively, a laser beam may be used to make the
holes
after the smoking article has been assembled, using an on-line or on-machine-
line
io system. In the latter case, the holes are burnt into the filter by the
focused laser beam,
and hence pass through the paper or papers wrapped around the filter (tipping
wrapper
and plug wrap) and into the material within the filter.
The location of the holes along the filter length can modify the filtering and
dilution
effects, in particular if the holes are positioned with reference to
individual components
of a multi-segment filter. In smoking articles having the above described
"split
tipping", this split tipping has been found to improve vent level control at
higher flow
rates.
The vent flow measurements for three different ventilation systems are
depicted in
Figure 5. Plot A shows data for a test cigarette where all of the filter
ventilation is
produced by split tipping, with a 20MM split gap. Plot B shows data for a
commercial
control cigarette with on-machine laser (OML) ventilation on the filter. Plot
C shows
data for a test cigarette where part of the ventilation is produced by slit
tipping (with a
iomm gap) and partly by an OML zone in the filter.
Under ISO machine puffing conditions, i.e. at an average ISO flow rate drawn
through a
cigarette of 17.5 cm3 per second (or 1.050 L/min), filter ventilation is
measured as the
percentage air which flows in through the ventilation holes on the cigarette
filter
relative to the total puff volume, or average flow drawn through the
cigarette. The
ventilation level that is achieved influences the ISO yields of tar, nicotine
and CO from
the product. When consumers smoke cigarettes they may take larger puff volumes
and/or draw at greater flow rates through the cigarette relative to ISO.
Therefore,
consumers may take yields from conventional cigarettes in excess of the ISO
machine
smoked values; one of the reasons for this increase in yield is that the
effective 'filter
ventilation' is reduced at draw rates above ISO (as depicted by Plot B in
Figure 5).
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 8 -
In contrast, with the 'split tip' system of ventilation (with no additional
ventilation
holes), as the flow rate through the cigarette is increased above the ISO flow
rate the
'effective ventilation' is not reduced to the degree that would be expected in
conventional products. In fact the flow versus pressure drop relationship
through the
'split tip' area is almost linear such that as the flow in the cigarette rod
is increased the
flow through the 'split tip' increases almost in the same proportion.
Therefore, there is
very little loss in 'effective ventilation' under more intense smoking (see
Plot A in
Figure 5).
It should be obvious to those skilled in the art that split tipping is only
effective at
/o influencing yields from human or machine smoking when the ventilation
zone is not
blocked. This means that split tipping is not effective using the Health
Canada Intense
smoking (machine) regime.
As it is difficult to predict the exact level of ventilation that can be
achieved due to split
tipping alone some trial samples were manufactured and on-machine laser used
to 'fine
/5 tune' the sample filter ventilation and achieve the required ISO yields
(for example,
used in generating Plot C of Figure 5). As seen in this plot the effect of
split tipping is
evident using the combined ventilation system.
In the embodiment illustrated in Figure 3, the ventilation holes 131 are
positioned
annually around the circumference of the filter 112, having been burnt by a
focused
20 laser beam (an On Machine Laser). The holes extend through the tipping
wrapper 115,
through the underlying plug wrap 123 and any optional inner plug wrap (not
shown),
and a short distance into the filter body.
Ventilation holes may be arranged as a row or zone around the circumference of
the
filter, approximately 11 to 16 mm from the mouth end of the filter. In the
particular
25 embodiment illustrated, the ventilation holes 131 are provided 13 mm
from the mouth
end 113 of the filter 112. This means that the ventilation holes 131 are
aligned with the
central filter section 121b.
Ventilation holes made by laser typically have a depth of the order of 1 to 2
mm,
although they may extend further into the body of the filter, having a depth
of greater
30 than 2 mm, for example a depth of 2 to 3.5 mm and/or a depth that is at
least 25% of
the diameter of the filter, or even 25 to so% of the diameter of the filter.
In some
embodiments, the smoking article comprises at least one ventilation hole
extending
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 9 -
though a tipping wrapper and any plug wrap into the filter. The hole may
extend to a
depth such that air drawn in through the ventilation hole enters a central
region of the
filter. Alternatively, one or more holes may be provided and arranged to
control the
passage of the diluting air through the filter. For example, the holes may be
of varying
depths or may be aligned with predetermined parts of the filter.
Conventional cigarettes typically include cellulose acetate (CA) tow as a
filter material.
The cellulose acetate is usually treated with plasticizers which bind adjacent
fibres at
their points of contact, giving the fibrous tow increased strength and
structural
integrity. Suitable plasticizers for this use include triacetin (glycerin
triacetate), TEC
io (triethyl citrate) and PEG 400 (low molecular weight polyethylene
glycol). Plasticized
cellulose acetate tow is also known to improve the selective removal of semi-
volatile
compounds found in smoke (e.g. phenol, o-cresol, p-cresol and m-cresol). In
some
embodiments of the invention, at least one of the filter sections includes
cellulose
acetate. In some embodiments, the mouth end filter section (illustrated as
filter section
21C in Figure 1.) comprises or consists essentially of cellulose acetate tow,
and preferably
plasticized cellulose acetate tow.
Whilst fibrous filter material is able to reduce the particulate phase
constituents with
the tar and nicotine, little selective reduction occurs. What is more, since
cellulose
acetate filters have little or no effect on volatile constituents, increasing
filtration
efficiency increases the ratios of their yields relative to tar and nicotine.
However, the
presence of a cellulose acetate filter section can enhance the consumer
acceptability of
the smoking articles of the present invention and this may be especially the
case where
the cellulose acetate filter section is positioned at the mouth end of the
filter.
In order to further enhance the adsorption characteristics of the filter of
the smoking
articles, porous adsorbents may be included in order to remove some of the
volatile
constituents from the mainstream smoke. Active Carbon (AC) is a non-selective
adsorbent which is widely used in cigarette filters and can reduce a broad
range of
volatile smoke constituents to a significant extent via physisorption.
The adsorption characteristics of the porous carbon may be enhanced by
engineering
the porous surface of the carbon, to provide what may be called "High Activity
Carbon"
(HAC). Thus, in some embodiments of the invention, at least one section of the
filter
comprises high activity carbon.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 10 -
The high activity carbon may be incorporated into a filter section of a
smoking article in
a cavity, or dispersed ("Dalmatian" style) throughout a plug of filter
material (such as
cellulose acetate). In some embodiments, the high activity carbon may be
applied to
the inner surface of the (inner) plug wrap of the filter section, thereby
lying between the
plug wrap and the plug of filter material.
In some embodiments, the filter section adjacent the rod of smokeable material
(illustrated as section 2ia in Figure 1.) comprises high activity carbon. In
some
embodiments, a filter section is loaded with between 20 and 80 mg, and
preferably
with about 50 mg, high activity carbon.
io The high activity carbon may be polymer-derived. For example, it may be
a porous
carbon bead material derived from polystyrene.
One possible type of high activity carbon that may be used in the smoking
articles of the
invention comprises substantially spherical particles of polymer-derived
carbon has
been prepared by a proprietary process (Von Blucher and De Ruiter 2004; Von
Blucher
et el 2006; Bohringer and Fichtner 2008) and is available from Blucher GmbH
(Germany).
These polymer-derived, high activity carbon granules possess a pore structure
which is
different from the carbon commonly used in commercial cigarettes, which is
typically
derived from coconut shells. As a result it has superior adsorption
characteristics for a
range of volatile smoke toxicants. The polymer-derived carbon performs well
under
both ISO and HCI smoking regimes and with regular and smaller circumference
cigarettes, although some limitations have been observed under higher flow-
rate
smoking conditions in the removal of acetaldehyde.
The process used to prepare the polymer-derived carbon is depicted in Figure
4. The
polymer-derived active carbon is produced using a batch process with indirect
heated
rotary kilns, under reduced pressure in an inert atmosphere. After preparation
of the
spherical polymer feed-stock the material is thermally stabilised using an
excess of
oleum. Subsequently, the material is slowly heated to 5oo C, resulting in the
release of
predominantly SO2 and H20 and the carbonisation of the polymer. The resulting
carbon has an initial pore system which is not accessible for typical
adsorptives. To
create a porous system suitable for adsorption, the material is further heated
to about
900 to i000 C for activation with oxidising agents (steam). This establishes a
pore
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 11 -
system consisting mainly of micropores with pore sizes between 0.7 and 3 nm.
Subsequent activation with CO2 leads to the formation of predominantly larger
mesopores in the range of 3 to 80 nm. Combining the steam and CO2 activation
steps
offers a flexible strategy for producing desired pore characteristics.
The polymer-derived carbon, being a synthetic material, possesses a much more
closely
defined spherical shape, together with a more uniform particle size. The
polymer-
derived material possesses a lower density, and has a lower ash content
reflecting the
synthetic nature of the polymer feedstock in comparison to a natural coconut
shell as
starting materials for the carbonization processes.
/o Most smoke constituents are adsorbed more effectively by the polymer-
derived carbon
under the ISO regime than by activated coconut carbon, with reductions of the
order of
8o-95% observed with smoke constituents other than formaldehyde, acetaldehyde,
hydrogen cyanide (HCN) and toluene (50-60% reductions). Under HCI conditions,
cigarettes with conventional coconut carbon provide reductions of the order of
25-45%
/5 for most smoke constituents, other than acetaldehyde (16%). The
cigarettes including
polymer-derived carbon reduce most smoke constituent yields by 6o-9o%, other
than
acetaldehyde and HCN (15-30%).
Chemisorption is also capable of removing toxicants from mainstream smoke,
including high volatility aldehydes and HCN. An amine-functionalised resin
offers the
20 potential for the nucleophilic capture of aldehydes from mainstream
smoke, and due to
its weakly basic nature it may also be used for the removal of HCN from
mainstream
smoke.
Thus, in some embodiments of the invention, at least one section of the filter
comprises
an ion exchange resin. The ion exchange resin has a surface activated amine
which may
25 bind effectively to selected vapour phase aldehyde constituents and
hydrogen cyanide.
The amine-functionalised resin material may be incorporated into a filter
section of a
smoking article in a cavity, or dispersed ("Dalmatian" style) throughout a
plug of filter
material (such as cellulose acetate). In some embodiments, the amine-
functionalised
resin may be applied to the inner surface of the (inner) plug wrap of the
filter section,
30 thereby lying between the plug wrap and the plug of filter material.
In one possible arrangement, the central filter section is loaded with between
5 and 40
mg, and preferably about 20 mg, of an amine-functionalised resin.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 12 -
DIAION CR2o is a commercially available type of amine-functionalised ion
exchange
resin bead (manufactured by Mitsubishi Chemical Corporation). It has polyamine
groups as chelating ligands which are bonded onto a highly porous crosslinked
polystyrene matrix. CR2o shows large affinity for transition metal ions. The
exact type
of amine groups produced by functionalisation cannot be precisely controlled
and
several different types could be present on the resins.
Commercial grade CR2o (hereafter referred to as CR2oC) was found to have a
characteristic odour which is incompatible with conventional consumer
acceptable
cigarette smoke character when incorporated into cigarettes. However,
modification to
io the synthesis conditions by Mitsubishi significantly reduced the
intensity of this odour,
resulting in a "low-odour" grade of CR2o (hereafter referred to as CR2oL). In
this work,
unless otherwise stated, all results obtained refer to CR2oL. This material
possessed a
bead size of 600 mm, density of 0.64 g/cm3, a 15% by weight water content, and
total
exchange capacity of 0.92 meq/cm3. Various other types of CR2o are made by
Mitsubishi Chemical Corporation, including CR2oD and CR2oHD and these may be
suitable for use in smoking articles.
Some CR2o beads are provided in water and, in order to make them suitable for
use in
a cigarette filter application, it may be necessary to remove at least some of
the water.
In some embodiments, the water is removed and the material is dried to
approximately
15% or less moisture. In alternative embodiments, a higher moisture content
are also
acceptable in the filter of smoking articles.
CR2o, including specifically CR2oL, may be incorporated into the filters of
smoking
articles of the present invention. In comparison to filters containing
conventional
carbon, CR2oL offers superior reductions for HCN, formaldehyde and
acetaldehyde.
In some embodiments, of the present invention, the smoking articles are based
upon a
novel format. This may, in part, be in order to accommodate the longer filter
according
to some embodiments described herein. For example, in some embodiments the
smoking articles comprise three or more filter sections with a total length of
approximately 37 mm, the tipping length (that is, the distance from the mouth
end of
the smoking article to the furthermost edge of tipping wrapper) is 42 mm. A
conventional king size cigarette will generally have a 15 to 27 mm filter. The
extended
length of the filter of some of the smoking articles of the invention results
in the dual
effect of increased smoke filtration due to the longer residence time of the
smoke in the
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 13 -
filter and there being less smokeable material to be combusted due to reduced
length of
the smokeable material rod.
In some embodiments, the filter has a length of at least 30 mm, 31 mm, 32 mm,
33 mm,
34 mm or at least 35 mm. Alternatively or in addition, the filter may have a
length of
no more than 50 mm, 49 mm, 48 mm, 47 mm, 46 mm, 45 mm, 44 mm, 43 mm, 42 mm,
41 mm, or no more than 40 mm.
To counterbalance this decrease in smokeable material rod length, a slow
burning
paper wrapper may be used to circumscribe the rod of smokeable material. This
can
enable the smoker to achieve the same number of puffs per smoking article as
with a
io conventional length rod of smokeable material.
In alternative embodiments, the smoking article may be provided with a rod of
smokeable material which has the same or a similar length as the rod of
smokeable
material in a conventional cigarette. This will render the smoking article
longer than a
conventional cigarette, as a result of the longer filter.
In some embodiments, the smoking article has a so-called "demi slim"
circumference of
21 mm compared with the standard "king size" circumference of 24.6 mm. The
smoking articles may have a standard "king size" length of 83 mm (including
both the
rod of smokeable material and the filter).
In addition to the modifications made to the filter of the smoking articles in
order to
enhance the reduction in toxicants present in the mainstream smoke, further
technologies relating to the smokeable material may be used, to complement the
effects
of the filter or to counterbalance them where desired.
Treated tobacco blends are described herein which have been treated by
processes that
allow the removal of protein and polyphenols from tobacco, with a beneficial
effect on
the smoke toxicant yields. The tobacco treatment may be carried out on cut,
flue-cured
tobacco. Briefly, the tobacco blend is subjected to an aqueous extraction step
and the
extract is subsequently passed through two stages of filtration to remove
polyphenols
and soluble peptides. The residual tobacco solids are treated with protease to
remove
insoluble proteins. After washing and enzyme deactivation, the tobacco solids
and
filtered aqueous extract are re-combined. The treatment process results in
material
referred to herein as blend treated tobacco (BTT), which results in reduced
smoke
yields of phenolics, aromatic amines, HCN, and a number of other nitrogenous
smoke
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 14 -
constituents; however, there are also increases in the yields of formaldehyde
and
isoprene. The blend treated tobacco retains the structure of the original
tobacco and
may be incorporated into rods of smokeable material for inclusion in smoking
articles
using conventional cigarette making equipment, without the need for
reconstitution
into a sheet material.
In some embodiments of the invention, the smokeable material comprises a blend
treated tobacco.
The tobacco material to be extracted may be strip, cut, shredded or ground
tobacco. In
some embodiments, the tobacco is shredded tobacco. Other forms of tobacco may,
/o however, be extracted using the methods described herein.
The tobacco material may be mixed with a solvent for extraction to form a
slurry. The
solvent may be added to the tobacco material in a ratio of between 10:1 and
5o:1,
preferably between 20:1 and 4o:1 and most preferably between 25:1 and 3o:1 by
weight.
In one embodiment, the solvent is added to the tobacco material in a ratio of
27:1 by
/5 weight.
The solvent may be an organic solution, but preferably is an aqueous solution
or is
water. At the very start of the extraction process, the solvent is usually
water, but it can
also contain alcohols such as ethanol or methanol, or it can contain a
surfactant. Other
solvents could be used, depending on the particular constituents to be
extracted from
20 the tobacco.
The extraction may be performed at about 15-85 C, and preferably is performed
at
about 65 C. It is preferable for the slurry to be continually stirred during
extraction,
such that the tobacco remains in suspension. Extraction should be performed
for
between 15 minutes and two hours. In a preferred embodiment, extraction is
25 performed for approximately 20 minutes.
During extraction, soluble tobacco components are removed from the tobacco
material
and enter solution. These include nicotine, sugars, some proteins, amino
acids, pectins,
polyphenols and flavours. Up to about 55% of the initial tobacco weight may
become
solubilised. It is important that the pectins in the tobacco fibre remain
cross-linked
30 throughout the extraction and treatment process in order to maintain the
fibrous
structure of the tobacco. Accordingly, calcium may be added to the solvent
used to
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 15 -
extract the tobacco and to any solutions used in the downstream processing
procedures.
Following extraction, the slurry may be drained to allow the liquid filtrate
(the "mother
filtrate") to be collected. Meanwhile, the insoluble tobacco residue may be
further
extracted by counter-current washing as it is conveyed, so that as many
soluble
constituents as possible are removed from the tobacco.
Fresh solvent may be applied to the tobacco and the filtrate (the "wash
filtrate") is
collected. The wash filtrate may be recycled by being applied to the incoming
tobacco
residue travelling on the belt at an upstream point. The collection and
upstream
io reapplication of wash filtrate to incoming tobacco residue may be
repeated a number of
times, preferably three, four or even five times. Thus, the final wash
filtrate that is
collected at the head of the belt may be concentrated in those soluble tobacco
constituents that have been removed from the tobacco residue as it travels the
length of
the filter. The final wash filtrate may be further recycled by being added to
fresh
tobacco to form a tobacco slurry, ready for extraction. For example, the final
wash
filtrate may be added into the tobacco mix tank where a tobacco slurry is
formed prior
to extraction. The extraction process may thus be a continual process in which
fresh
tobacco is extracted using recycled wash filtrate. Only at start-up of this
extraction
process is tobacco extracted with fresh solvent. Once the extraction process
has begun,
no fresh solvent is used in the extraction, but the solvent is solely made up
of recycled
wash filtrate.
As the extraction process continues, the extract thus becomes more
concentrated in
soluble tobacco constituents. These constituents include those that entered
solution
during primary extraction in the extraction tank (forming the mother
filtrate), as well
as those that entered solution during secondary extraction on the horizontal
belt filter
(forming the wash filtrate).
The final filtrate thus comprises both the mother and wash filtrates. In so
doing, the
tobacco residue that results after filtration is devoid of those constituents
that are
soluble in the solvent used for extraction. The extracted tobacco may be
squeezed at the
end of filtration, so as to remove any excess liquid from it. The extracted
tobacco
emanating from the horizontal belt filter is thus typically in the form of a
dewatered
mat.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 16 -
The final filtrate, hereinafter referred to as the tobacco extract, may be
subsequently
processed to remove those constituents not desired in the final tobacco
product.
Undesirable constituents include proteins, polypeptides, amino acids,
polyphenols,
nitrates, amines, nitrosamines and pigment compounds. The levels of
constituents
which may be considered desirable, such as sugar and nicotine, may, however,
remain
unaffected so that the flavour and smoking properties of the extracted tobacco
are
comparable to those of the original material.
In a preferred embodiment, the tobacco extract is treated to remove proteins,
polypeptides and/or amino acids. Up to 6o% of the proteins contained in the
original
io tobacco material may be removed using an insoluble adsorbent such as
hydroxyapatite
or a Fuller's Earth mineral such as attapulgite or bentonite. The tobacco
extract is
preferably treated with bentonite, to remove polypeptides therefrom. Bentonite
may be
added to the extract in an amount of 2-4% of the weight of tobacco initially
extracted.
Alternatively, the tobacco extract may be fed into a tank containing a slurry
of bentonite
in water. A suitable slurry contains approximately 7 kg of bentonite in
approximately
64 kg water (quantities per hour), for example, 7.13 kg bentonite in 64.18 kg
water
(quantities per hour). In any case, the bentonite concentration should be high
enough
to substantially reduce the protein content of the tobacco extract, but not so
high as to
additionally adsorb nicotine from it. Bentonite treatment may also be
effective in the
removal of pigment compounds found in tobacco extract which, if not removed,
tend to
darken the extract after concentration. When sufficient bentonite is used to
treat the
extract, the reduced amount of pigment compounds may result in a product that
is not
overly darkened in appearance.
Following bentonite treatment, the tobacco extract may be purified from the
slurry by
centrifugation and/or filtration. The tobacco extract may also, or
alternatively, be
treated to remove polyphenols therefrom.
Polyvinylpolypyrrolidone (PVPP) is an insoluble adsorbent for polyphenols,
traditionally used in the brewing industry to remove polyphenols from beer.
PVPP in
an amount of 5-1o% of the weight of tobacco initially extracted may be added
to the
extract. This amount of PVPP is capable of removing between 50 and 90% of the
polyphenols in solution. The optimum pH for removal of polyphenols from the
tobacco
extract by PVPP is believed to be about 3. The efficiency of adsorption by
PVPP may
therefore be increased by reducing the pH of the extract via the addition of a
suitable
acid, such as hydrochloric acid.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 17 -
As an alternative to using PVPP to adsorb the polyphenols, one or more enzymes
may
be added to the tobacco extract to degrade the polyphenols therein. A suitable
enzyme
is laccase (urishiol oxidase). The invention is not, however, limited to
methods for
removing only proteins and/or polyphenols from tobacco. Alternative or
additional
enzymes, agents or adsorbents may be used to remove other undesirable tobacco
constituents from the tobacco extract. Examples of further undesirable tobacco
constituents that could be removed from the extract include nitrates, amines
and
nitrosamines.
If a plurality of constituents is to be removed from the tobacco extract, a
number of
/o tanks may be set up in series, each one comprising a different enzyme,
agent or
adsorbent, in order for a chosen complement of undesirable constituents to be
removed. Alternatively, a single tank may contain a plurality of enzymes,
agents or
adsorbents so that the undesirable constituents may be removed in a single
step. For
example, a bentonite or PVPP holding tank could comprise one or more
additional
/5 enzymes, agents or adsorbents so as to remove not only protein or
phenols from the
tobacco, but one or more further undesirable constituents also.
Following treatment of the tobacco extract to remove the selected undesirable
constituents, the extract is preferably concentrated to a solids concentration
of between
20 and 50% by weight. Concentrations of up to io% solids are most efficiently
achieved
20 using reverse osmosis. A further concentration to approximately 40%
solids may be
achieved by means of a falling film evaporator. Other methods of concentration
can be
used and will be known to a person skilled in the art. The concentrated
tobacco extract
may be subsequently recombined with the extracted tobacco.
The tobacco, having been extracted in an aqueous solution as discussed above,
25 however, is preferably further extracted to remove one or more further
undesirable
constituents before being recombined with the concentrated tobacco extract.
Further
extraction of the tobacco may be performed using an enzyme specifically
selected for
removal of the constituent of choice. In a preferred embodiment, the enzyme is
a
proteolytic enzyme for removal of protein from the tobacco. The enzyme is
preferably a
30 bacterial or fungal enzyme and, more preferably, is an enzyme used
commercially in the
food and detergent industries. The enzyme may be selected from the group
consisting
of SavinaseTM, Neutrasem, EnzobakeTM and A1calaseTM, which are all available
from
Novozymes A/S. The proteolytic enzyme is preferably added to the tobacco in an
amount of between 0.1 and 5% by weight of the tobacco material. For example,
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 18 -
SavinaseTM may be added to the tobacco in an amount of approximately 1% by
weight.
The tobacco may be reslurried in a solution of the chosen enzyme. The ratio of
water to
tobacco in the slurry should be between 10:1 and 5o:1, preferably between 20:1
and
40:1 and most preferably between 25:1 and 3o:i by weight. In a particularly
preferred
embodiment, the ratio of water to tobacco is 27:1 by weight.
The pH of the tobacco/enzyme mixture should be that which promotes optimal
enzyme
activity. Accordingly, it may prove convenient to feed the dewatered mat of
tobacco
into a tank in which the pH is adjusted, for example, by the addition of a
base such as
sodium hydroxide. The pH-adjusted tobacco may then be fed into an enzyme
dosing
io tank for mixing with the enzyme of choice. The tobacco/enzyme mixture
may
subsequently be fed into a plug flow reactor, where the enzymic extraction is
performed. The enzymic extraction should be carried out at the temperature
promoting
optimal enzyme activity. Preferably, a narrow temperature range, such as 30-40
C,
should be used to avoid denaturing the enzyme. The optimum working conditions
when SavinaseTM is the chosen enzyme are 57 C and pH 9-11. The enzymic
extraction
should be carried out for at least 45 minutes; any shorter duration is
believed to be
insufficient for a proteolytic enzyme to degrade tobacco proteins.
Of course, multiple enzymic extractions could be carried out if there are
multiple
constituents to be removed from the tobacco. These could be performed in
series or
multiple enzymes could be added to the tobacco in a single treatment step.
It also remains possible for the enzyme to be included in the very first
extraction step in
the treatment process, rather than forming a subsequent separate extraction
step.
Following enzymic extraction, the insoluble tobacco residue may be washed with
a salt
solution, preferably a sodium chloride solution, to rinse it free of enzyme.
Salt rinsing
may be performed in a sequential, counter-current fashion.
Salt and water rinsing, however, may not be sufficient to remove all of the
enzyme from
the tobacco. The washed tobacco may also be treated to deactivate any residual
enzyme
remaining in the tobacco following the salt and water rinses. This may be done
by
steam treating the tobacco sufficiently to deactivate the enzyme, but not so
much that
the tobacco loses its fibrous form. In an embodiment, steam treating is
carried out at
about 98 C for about four minutes, but the residence time may be increased to
about 10
minutes if desired. Alternatively, the tobacco may be heat treated to
deactivate the
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 19 -
enzyme, for example by microwaving or baking the tobacco. In another
embodiment,
the enzyme may be deactivated by chemical denaturation; steps should however
be
taken to remove the chemical from the tobacco.
The processed tobacco may then be recombined with the concentrated tobacco
extract.
Adding the treated extract back to the extracted tobacco ensures retention of
water
soluble flavour components of tobacco and nicotine in the final product.
Recombination therefore results in a tobacco product that has similar physical
form
and appearance, taste and smoking properties to the original material, but
with
substantially reduced levels of protein, polyphenols or other constituent(s)
of choice.
/o Recombination may be achieved by spraying the tobacco extract onto the
tobacco. The
amount of the original extract being recombined with the processed tobacco
depends
upon the amount that was lost during treatment of the extract to remove
selected
constituents, and will vary from one type of tobacco to the next.
A standard drying process may be used to dry the treated tobacco, either
before, during
/5 or after recombination with the treated tobacco extract. The starting
moisture content
of the treated tobacco is typically approximately 70-80%. In a preferred
embodiment,
the moisture content after drying should be approximately 14%. A heated dryer,
such
as an apron dryer, may be used to reduce the starting moisture content in the
tobacco
to approximately 30%. A second heated dryer, such as an air dryer, may then be
used
20 to further reduce the moisture content to approximately 14%.
The final dried product may subsequently be processed into a finished form,
such as a
sheet, which, when shredded, can form all or part of a cigarette filler. Owing
to as
much as 30% of the original constituents of tobacco being removed therefrom
during
the extraction and treatment process, however, the concentration of remaining
25 constituents per unit weight of tobacco is increased in the finished
product compared to
the original material. These constituents include cellulose, which, together
with sugars
and starches, may produce harmful volatile materials such as acetaldehyde and
formaldehyde in smoke when combusted.
Another approach to reducing smoke toxicant yields is to dilute the smoke with
glycerol
30 and this may be done by forming a so-called "tobacco substitute sheet"
(TSS) which
includes a large proportion of glycerol, for example up to 6o% by weight of a
glycerol.
Analysis of mainstream smoke from cigarettes included such TSS in the
smokeable
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 20 -
material showed reductions in yields of most measured constituents, other than
some
volatile species.
In some embodiments of the invention, the smokeable material comprises a
tobacco
substitute sheet.
Incorporation of the tobacco substitute sheet (TSS) into a tobacco blend
reduces the
quantity of tobacco in a cigarette, thereby further diminishing the overall
potential for
the cigarette to generate toxicants. When heated, the glycerol included in the
TSS
releases into the smoke stream contributing to the total amount of particulate
smoke,
measured as nicotine-free dry particulate matter (NFDPM, also known as "tar").
As
io most cigarettes are designed to meet a specific NFDPM yield value,
incorporation of
glycerol into the smoke stream effectively results in a reduced contribution
of the
tobacco combustion products to the overall NFDPM value: this process is termed
"dilution". The incorporation of TSS into smoking articles results in
reductions in a
wide range of smoke constituents, including both particulate and vapour phase
toxicants. In vitro toxicological tests showed reductions in the activity of
smoke
particulates in proportion to their glycerol content. Human exposure to
nicotine was
reduced by a mean of 18% as determined by filter studies and by 14% using 24
hour
urinary biomarker analysis. Smoke particulate exposures were reduced by a mean
of
29% in filter studies and by similar amounts based on urinary 4-
(methylnitrosamino)-
143- pyridy1)-1-butanol concentrations. These results show that reducing
exposure to
some smoke toxicants is possible using a tobacco substitute sheet.
In some embodiments, the smoking article includes a tobacco substitute sheet
material
comprising a non-combustible inorganic filler material, a binder (such as, for
example,
and alginic binder) and aerosol generating means.
Advantageously the tobacco substitute sheet material comprises as the main
components thereof, non-combustible inorganic filler, binder and aerosol
generating
means, with these three components together preferably comprising at least 85%
by
weight of the tobacco substitute sheet material, preferably greater than 90%,
and even
more preferably total about 94% or more by weight of the tobacco substitute
sheet
material. The three components may even be l00% of the tobacco substitute
sheet
material. The remaining components are preferably one or more of colorant,
fibre, such
as wood pulp, or flavourant, for example. Other minor component materials will
be
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 21 -
known to the skilled man. The tobacco substitute sheet material is therefore a
very
simple sheet in terms of its constituents.
As used herein, the term' tobacco substitute sheet material' means a material
which
can be used in a smoking article. It does not necessarily mean that the
material itself
will necessarily sustain combustion. The tobacco substitute sheet material is
usually
produced as a sheet, then cut. The tobacco substitute sheet material may then
be
blended with other materials to produce a smokeable filler material.
In some embodiments, a smoking article comprises a wrapped rod of a smokeable
filler
material, the smokeable filler material consisting of a blend which
incorporates tobacco
/o substitute sheet material comprising a non-combustible inorganic filler,
an alginic
binder and aerosol generating means, the smoking article having an aerosol
transfer
efficiency ratio of greater than 4Ø As used herein, the aerosol transfer
efficiency is
measured as the percentage aerosol in the smoke divided by the percentage
aerosol in
the smokeable filler material. Preferably the aerosol transfer efficiency is
greater than 5,
and more preferably greater than 6.
The smokeable material used in the smoking articles of the present invention
may
comprise a blend consisting of not more than 75% by weight of the tobacco
substitute
sheet material.
Preferably the inorganic filler material is present in the range of 6o-9o%,
and is more
preferably greater than 70% of the final sheet material. Advantageously the
inorganic
filler material is present at about 78% by weight of the final sheet material,
but may be
present at higher levels, for example, 8o%, 85% or 90% by weight of the final
sheet
material.
In some embodiments, the non-combustible filler advantageously comprises a
proportion of material having a mean particle size in the range of 500 lam to
75 lam or
in the range of 400 lam to 100 lam, a mean particle size of more than 125 lam,
or more
than 150 lam. In some cases, it may be advantageous for the mean particle size
to be
about 170 lam, or in the range of 170 lam to 200 jum. This particle size is in
contrast to
that conventionally used for food grade inorganic filler materials in
alternative tobacco
products, namely a particle size of about 2-3 lam. The range of particle size
seen for
each inorganic filler individually may be from 1 [tm-1 mm (1000 lam). The
inorganic
filler material may be ground, milled or precipitated to the desired particle
size.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 22 -
The inorganic filler material may be one or more of perlite, alumina,
diatomaceous
earth, calcium carbonate (chalk), vermiculite, magnesium oxide, magnesium
sulphate,
zinc oxide, calcium sulphate (gypsum), ferric oxide, pumice, titanium dioxide,
calcium
aluminate or other insoluble aluminates, or other inorganic filler materials.
The density
range of the materials may be in the range of 0.1 to 5.7 g/cm3. In some
embodiments,
the inorganic filler material has a density that is less than 3 g/cm3, less
than 2.5 g/cm3,
less than 2.0 g/cm3 or less than 1.5 g/cm3. An inorganic filler having a
density of less
than 1 g/cm3 may be desirable. A lower density inorganic filler reduces the
density of
the product, thus improving the ash characteristics.
If a combination of inorganic filler materials is used, one or more of the
fillers may
suitably be of a small particle size and another may be of a larger particle
size, the
proportions of each filler being suitable to achieve the desired mean particle
size. The
static burn rate required in the finished smoking article may be achieved
using an
appropriate blend of tobacco and tobacco substitute sheet material in the
smokeable
filler material.
In some embodiments, the inorganic filler material is not in agglomerated
form. The
inorganic filler material should require little pre-treatment, other than
perhaps size
gradation, before use. The binder may be present in the range of about 5-13%,
less than
10% or less than 8%, by weight of the final filler material. The binder may be
about
7.5% by weight or less of the final sheet material. If the binder is a mixture
of alginate
and non-alginate binders, then the binder may comprise at least so% alginate,
at least
6o% alginate or at least 70% alginate. The amount of combined binder required
may
suitably decrease when a non-alginate binder is utilised. The amount of
alginate in a
binder combination advantageously increases as the amount of combined binder
decreases. Suitable alginic binders include soluble alginates, such as
ammonium
alginate, sodium alginate, sodium calcium alginate, calcium ammonium alginate,
potassium alginate, magnesium alginate, triethanol-amine alginate and
propylene
glycol alginate. Other organic binders such as cellulosic binders, gums or
gels can also
be used in combination with alginic binders. Suitable cellulosic binders
include
cellulose and cellulose derivatives, such as sodium carboxymethylcellulose,
methyl
cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose or cellulose
ethers. Suitable
gums include gum arabic, gum ghatti, gum tragacanth, Karaya, locust bean,
acacia,
guar, quince seed or xanthan gums. Suitable gels include agar, agarose,
canageenans,
furoidan and furcellaran. Starches can also be used as organic binders. Other
suitable
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 23 -
gums can be selected by reference to handbooks, such as Industrial Gums, E.
Whistler
(Academic Press). Much preferred as the major proportion of the binder are
alginic
binders. Alginates are preferred in the invention for their neutral taste
character upon
combustion.
In some embodiments, the aerosol generating means is present in the range of 5-
20%,
or is included in an amount less than 15%, greater than 7% and/or greater than
io%. In
a particular embodiment, the aerosol generating means is included in an amount
of less
than 13%. In embodiments, the aerosol generating means is between ii% and 13%,
or is
about 11.25% or 12.5%, by weight of the final sheet material. Suitably the
amount of
/o aerosol generating means is selected in combination with the amount of
tobacco
material to be present in the blend comprising the smokeable filler material
of a
smoking article. For example, in a blend comprising a high proportion of sheet
material
with a low proportion of tobacco material, the sheet material may require a
lower
loading level of aerosol generating means therein. Alternatively in a blend
comprising a
/5 low proportion of sheet material with a high proportion of tobacco
material, the sheet
material may require a higher loading level of aerosol generating means
therein.
Suitable aerosol generating means include aerosol forming means selected from
polyhydric alcohols, such as glycerol, propylene glycol and triethylene
glycol; esters,
such as triethyl citrate or triacetin, high boiling point hydrocarbons, or non-
polyols,
20 such as glycols, sorbitol or lactic acid, for example. A combination of
aerosol generating
means may be used.
An additional function of the aerosol generating means is the plasticising of
the sheet
material. Suitable additional plasticisers include water. The sheet material
may
suitably be aerated. The cast slurry thereby forms a sheet material with a
cellular
25 structure.
Advantageously the or a proportion of the aerosol generating means may be
encapsulated, preferably micro-encapsulated, or stabilised in some other way.
In such
cases the amount of aerosol generating means may be higher than the range
given.
Advantageously the smoking material comprises a colorant to darken the
material
30 and/or a flavourant to impart a particular flavour. Suitable colorant
materials, subject
to local regulations, can include molasses and malt extract, for example.
Finely ground,
granulated or homogenised tobacco may also be used. Industry approved food
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 24 -
colorants may also be used, such as Ei5oa (caramel), Ei51 (brilliant black
BN), Ei53
(vegetable carbon) or E155 (brown HT). Suitable flavourants include menthol
and
vanillin, for example. Other casing materials may also be suitable. In the
alternative,
the presence of vermiculite or other inorganic filler materials may give a
darker colour
to the tobacco substitute sheet material. The colorant may be present from o-
w% and
may be as much as 5-7% by weight of the final tobacco substitute sheet
material. In
some embodiments, the colorant is less than 7%, less than 6% or less than 5%
of the
final tobacco substitute sheet material. In some embodiments, the amount of
colorant
used is less than 4%, less than 3% or less than 2%. For example, caramel may
suitably
io be present in a range of o-5%, or less than about 2% by weight of the
final tobacco
substitute sheet material, or about 1.5%. Other suitable colorants include
molasses,
malt extract, coffee extract, tea resinoids, St. John's Bread, prune extract
or tobacco
extract. Mixtures of colorants may also be used.
If permitted under local regulations, flavourants may also be added to alter
the taste
and flavour characteristics of the tobacco substitute sheet material.
Advantageously, if a
food dye is utilised in the alternative it is present at o.5% by weight or
less of the final
tobacco substitute sheet material. The colorant may alternatively be dusted
into the
sheet after sheet manufacture.
Fibres, such as cellulose fibres, for example wood pulp, flax, hemp or bast
could be
added to provide the sheet material with one or more of a higher strength,
lower
density or higher fill value. Fibres, if added, may be present in the range of
o.5-io%, in
an amount of less than 5% or less than about 3% by weight of the final sheet
material.
Advantageously there is no fibrous material present in the sheet material,
cellulosic or
otherwise.
In some embodiments, the tobacco substitute sheet material is a non-tobacco
containing sheet. It shall be understood that at high levels of sheet material
inclusion in
the blend, e.g. at greater than 75% by weight of the blend, the combustibility
of the
blend is poor. This may be overcome by, for example, incorporating low levels
of up to
5-io% granular carbon in the tobacco substitute sheet material. The carbon is
preferably not an agglomerated carbonaceous material, i.e. the carbon is not
pre-
treated by mixing with another material to produce an agglomerate.
In some embodiments, the tobacco substitute sheet material is blended with
tobacco
material to provide smokeable filler material. Preferably the tobacco material
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 25 -
components in the blend are high quality lamina grades. Advantageously the
majority
of the tobacco material is cut tobacco. The tobacco material may comprise
between 20-
100% expanded tobacco of a high order expansion process, such as DIET for
example.
The filling power of such material is typically in the range of 6- 9 cc/g (see
GB 1484536
or US 4,340, 073 for example).
In some embodiments, the blend comprises less than 30% of other blend
components
apart from lamina, the other blend components being stem cut rolled stem
(CRS),
water treated stem (WTS) or steam treated stem (STS) or reconstituted tobacco.
The
other components may comprise less than 20%, less than io% or less than 5% of
the
io final weight of the tobacco material.
In some embodiments, a smoking article according to the invention comprises
tobacco
material treated with aerosol generating means. The tobacco material may be
treated
with aerosol generating means, but this is not essential for all blends of
tobacco
material and sheet material.
The amount of aerosol generating means added to the tobacco is in the range of
2-6%
by weight of the tobacco. The total amount of aerosol generating means in the
blend of
tobacco material and sheet material after processing is advantageously in the
range of
4-12% by weight of the smokeable material, preferably less than lo% and
preferably
more than 5% on a dry wt/wt basis.
In one embodiment, glycerol is added to the smokeable material comprising
tobacco
substitute sheet. This has been found to lead to a reduction in the level of
some
phenols. The glycerol may be added in an amount of about 1% by weight (in
addition to
any glycerol that might be included in the tobacco substitute sheet). It is
believed that
adding the glycerol to the TSS may be having a synergistic effect.
In some embodiments, the blend may also include a top flavour in order to
improve the
aroma and sensory performance of the blend.
A yet further approach to reducing smoke toxicant yields in the smoking
articles of the
present invention is to select tobacco blend components that exhibit low
levels of the
precursors of undesirable smoke constituents, such as TSNAs and metals. For
example,
the levels of TSNAs may be reduced by using specific (such as lighter) tobacco
blends
and by selecting parts of the tobacco plant that are low in nitrate, a
precursor of TSNAs.
In some embodiments, this involves using tobacco lamina. The person skilled in
the art
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 26 -
would be well aware of the ways in which the blending process may be adapted
to
provide a tobacco blend having these desired properties.
The tobacco blend may also comprise expanded tobacco, which is cut tobacco
that has
been expanded to reduce the mass of tobacco burnt in a cigarette One process
used to
process tobacco is called dry-ice expanded tobacco (DIET). The tobacco is
infused with
liquid carbon dioxide (CO2), in a pressure vessel, the pressure is lowered and
the liquid
CO2 drained off, resulting in solid CO2 or dry ice forming within the cellular
structure of
the tobacco. The tobacco is then heated quickly forcing the dry ice into
gaseous CO2,
which forces the structure of the cut tobacco leaf to expand to a volume which
is closer
/o to that of the leaf before the curing process. Expanded tobacco is
widely used in
commercial cigarettes and even more so in those of low ISO yields.
In one embodiment of the invention, the smokeable material is made up of a
blend of
50% blend treated tobacco (BTT), 15% tobacco substitute sheet (TSS), io% dry-
ice
expanded tobacco(DIET) and 25% Lamina, with addition of 1% glycerol and o.8%
of an
/5 added top flavour.
The above discussed filter and smokeable material technologies work in
combination to
provide a smoking article with substantial reductions in smoke toxicant
levels.
In some embodiments, the smoking articles according to the invention have a
reduction
(for example, compared to a conventional cigarette) in at least 75%, at least
90%, at
20 least 95% or in all of the key constituents of mainstream smoke, as
defined herein.
The so-called "key constituents" of MS referred to in connection with the
present
invention are those smoke constituents which have been identified in the
literature as
being undesirable (see, for example, The Scientific Basis of Tobacco Product
Regulation: Report of a WHO Study Group (2007) WHO Technical Report Series
945,
25 Geneva).
The reduction is preferably determined using an intense smoking regime where
the
ventilation is left open, as products have been designed to match at ISO and
the
ventilation blocking of the Health Canada regime negates the effect of the
split tip.
The reduction in yield of the key constituents is preferably at least 5% or at
least io% or
30 more.
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 27 -
Examples
The specifications of some examples of smoking articles according to
embodiments of
the present invention are set out in the tables below. Two prototypes are
described; one
is to deliver 1 mg of tar, the other 7 mg of tar. "Cig." is used as an
abbreviation for
"cigarette".
Table 1 - Smoking article characteristics
Parameter Type Unit i. mg Prototype 7 mg Prototype
Target Target
Cigarette length mm 83 83
Cig. circumference I11111 21.0 21.0
Filter length mm 37 37
Tipping width (pre-slitting) mm 64 64
In-pack moisture (for tobacco % 12.0 12.0
weight)
Density (at in-pack moisture) mg/cm3 305 305
Tobacco weight (at in-pack mg 490 490
moisture)
Weight cig. paper + adhesive mg 25 25
Weight applied cig. flavour mg 3.9 3.9
Rod weight (at in-pack mg 512 512
moisture)
Weight filter tip mg 283 283
Total cig. weight (at in-pack mg 818 818
moisture)
Non tobacco weight mg 332 332
Filter ventilation % 80 40
Ventilation type Split tipping and Split tipping and
On Machine Laser On Machine Laser
On-line laser position mm 13 13
Cig. pressure drop (open) mmWG 165 130
Filter plug pressure drop mmWG 135 110
(enc)
Ends stability mg/end <8 <8
Cig. Firmness % >72 >72
Tar mg 1.0 7.0
Nic mg 0.1 0.7
CO mg 1.0 7.0
Puff Number 7.2 7.4
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 28 -
Table 2 - Cigarette paper characteristics
Parameter Type Unit i. mg
Prototype 7 mg Prototype
Target Target
Name (LIPtech) CP50- (LIPtech) CP50-
23VGM2.0KCW 23VGM1.oKCW
Supplier Glatz Glatz
Bobbin Width 111111 23 23
Fibre Wood Wood
Permeability CU 50 50
Thickness lam 40 40
Grammage g/m2 23 23
Burn additive Type Potassium Citrate Potassium Citrate
Burn Additive content % 2.0 1.0
CaCO3 content % 30 30
Table 3 - Tipping paper characteristics
Parameter Type Unit i. mg
Prototype 7 mg Prototype
Target Target
Name ML03345146 ML03345146
Supplier Benkert Benkert
Width post machine slitting mm 21/11 21 / 11
Porosity CU o o
Type of perforation OML + ST OML + ST
Thickness lam 50 50
Grammage g/m2 42 42
Table 4 ¨ Filter materials for 7 mg version (440 mm Wg)
Component Overall Mouth end Middle Tobacco end
section
Base rod THS 100600 ABR060414 AAS060501 AAS060502
name
Tow N/A 8.0Y/28000 9.0Y/25000 9.0Y/25000
Rhodia Rhodia Rhodia
Plug wrap CP200-OU 0.4 23.omm 23.omm 23.omm
KCW 12000CU 12000CU 12000CU
Wattens Wattens Wattens
Plasticiser N/A Triethylcitrate Triethylcitrate Triethylcitrate
Adhesive 072-0143 072-0143 072-0143 072-0143
anchorage Henkel Henkel Henkel Henkel
Adhesive 5675A/B Forbo 334-2950 334-2950 334-2950
seam 1 Tobacoll Tobacoll Tobacoll
CA 02868222 2014-09-23
WO 2013/160671 PCT/GB2013/051031
- 29 -
Additive N/A N/A AFR HAC
Additive 70 0 20 50
weight (mg)
Table 5 ¨ Filter materials for 1 mg version (540 mm Wg)
Component Overall Mouth end Middle Tobacco end
section
Base rod THS 100601 ABR060414 AAS060501 AAS060503
name
Tow N/A 8.0Y/28000 9.0Y/25000 5.0Y/25000
Rhodia Rhodia Rhodia
Plug wrap CP200-OU 0.4 23.omm 23.omm 23.omm
KCW 12000CU 12000CU 12000CU
Wattens Wattens Wattens
Plasticiser N/A Triethylcitrate Triethylcitrate
Triethylcitrate
Adhesive 072-0143 072-0143 072-0143 072-0143
anchorage Henkel Henkel Henkel Henkel
Adhesive 5675A/B 334-2950 334-2950 334-2950
seam 1 Forbo Tobacoll Tobacoll Tobacoll
Additive N/A N/A CR2oD Synthetic
Carbon resin
Additive 70 0 20 50
weight (mg)
Table 6 summarises recognised machine smoking regimes used to generate smoke
data.
Table 6 - Smoking machine parameters
Smoking Abbreviation Puff Puff Puff Filter
Description Volume Duration Interval Vent
(ml) (s) (s) Blocking
(%)
ISO 3308/4387 ISO 35 2 6o o
Health Canada HCI 55 2 30 100
Intense
ISO WG 9 Intense WG9B 60 2 30 50
Option B
Table 7 shows the yields for the 7mg test product under both ISO and WG9
machine
smoking regimes and includes the ratios of WG9 to ISO. Table 8 provides
corresponding information relating to the control/comparator cigarette. The
data from
io both tables show that the ratios of WG9:ISO yields tend to be greater
for the control
product over those of the test product. This is as predicted due to the
reduction in
ventilation achieved at the higher cigarette puff volume (of the same puff
duration),
when smoking the test product using WG9 regime (where half vent holes and ST
are
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 30 -
occluded). This is therefore flow rate dependent and not volume dependent. If
none of
the ventilation holes and split tip ventilation were occluded the yields of
the test
product would be even lower at higher puff volume.
Table 7 - Mainstream smoke data for 7mg test product at ISO and WG9 smoke
regimes
Sample number G429 G429
Sample Description 7mg Test ST+OML 7mg Test ST+OML
Smoke Regime ISO WG9 Ratio
MS Data
Units Mean SD Mean SD WG9:ISO
(Labstat)
Puff count 7.6 0.3 10.0 0.3
NFDPM mg/cig 6.4 0.3 16.2 0.5 2.5
Nicotine mg/cig 0.64 0.03 1.45 0.04 2.3
CO mg/cig 5.4 0.3 14.0 0.3 2.6
NO vtg/cig 31.3 2.9 85.0 9.0 2.7
Table 8 - Mainstream smoke data for 7mg control product at ISO and WG9 smoke
regimes
Sample Number H285 H285
Sample Description 7mg Control OML 7mg Control OML
Smoking Regime ISO WG9 Ratio
MS Data
Units Mean SD Mean SD WG9:ISO
(Labstat)
Puff count 7.2 0.2 9.0 0.4
NFDPM mg/cig 7.1 0.4 23.9 2.4 3.4
Nicotine mg/cig o.58 0.04 1.52 0.14 2.6
CO mg/cig 7.4 0.4 22.4 0.8 3.0
NO vtg/cig 88.5 4.7 234.1 14.4 2.6
Examples of the reductions in the smoke yields, both in absolute terms and
io 'normalised' to NFDPM (Tar) and Nicotine, using the HCI smoking
regime are shown
in Table 9. Note that under the HCI regime the use of the split tipping
technology does
not contribute to the reductions in smoke component yields obtained for the
smoking
article according to the invention relative to the comparator/control.
Table 9 - Mainstream data for test and control cigarettes at HCI smoking
regime
Sample Number G429 H285
Absolute Change Change
change wrt wrt
Sample __ Description wrt
7mg Test 7mg Control
CA 02868222 2014-09-23
WO 2013/160671
PCT/GB2013/051031
- 31 -
ST+ OML OML Control NFDPM Nicotine
Smoking Regime HCI HCI
MS Data
Units Mean SD Mean SD % % %
(Labstat)
Puff count 9.1 0.5 8.2 0.3
NFDPM mg/cig 17.8 1.2 26.3 1.7
Nicotine mg/cig 148 0.06 1.59 0.04
CO mg/cig 15.7 0.8 22.7 1.1 -30.8 2.2 -25.7
NNN ng/eig 25.4 2.0 171.4 8.2 -85.2 -78.1 -84.1
NNK ng/eig 28.3 2.8 79.9 2.9 -64.5 -47.6 -61.9
Formaldehyde Ilg/cig 48.6 4.3 64.4 7.9 -24.6 11.5 -19.0
Acetaldehyde Ilg/cig 576 36 1122 40 -48.6 -24.1 -44.8
Acrolein Pg/eig 61.6 5.5 137.0 5.3 -55.0 -33.5 -51.7
B [a]P ng/eig 13.6 0.9 18.5 1.8 -26.4 8.8 -20.9
Benzene lug/eig 9.7 1.1 68.5 3.9 -85.9 -79.1 -
84.8
1,3 Butadiene Iig/eig 52.5 2.8 95.3 3.5 -44.9 -18.6 -
40.8
Test versus Control data: Negative (-) values = Reductions; Positive values =
Increases
Examples of the reductions in the smoke yields, both in absolute terms and
'normalised' to NFDPM (Tar) and Nicotine, using the WG9 smoking regime are
shown
in Table 10. Under the WG9 regime the use of the split tipping technology does
contribute to the reductions in smoke component yields obtained for the
smoking
article according to the invention relative to the comparator.
Table 10 - Mainstream data for test and control cigarettes at WG9 smoking
regime
Sample Number G429 H285
Absolute Change Change
change wrt wrt
mg Test mg Control
Sample Description wrt
NFDPM Nicotine
Control
OML OML cotine
Control
Smoking Regime WG9 WG9
MS Data
Units Mean SD Mean SD % % %
(Labstat)
Puff count 10.0 0.3 9.0 0.4
NFDPM mg/cig 16.2 0.5 23.9 2.4
Nicotine mg/cig 1.45 0.04 1.52 0.14
CO mg/cig 14.0 0.3 22.4 0.8 -37.5 -
7.8 -34.5
NNN ng/cig 22.8 2.8 143.9 9.2 -84.2 -76.6 -83.4
NNK ng/eig NQ NQ 70.9 4.5 >95.0 >95.0 >95.0
CA 02868222 2016-05-13
31511-37
- 32 -
Formaldehyde Ilecig 49.9 5.3 54.1 10.8 -7.6 36.3 -3.1
Acetaldehyde nicig 434 33 959 8o -54.7 -33.2 -52.5
Acrolein Ilgicig 44.8 2.9 120.6 13.1 -62.8 -45.2 -61.0
B[a]l) ng/cig 13.1 0.7 17.3 1.8 -24.2 11.9 -20.5
Benzene Ilgicig 9.5 1.3 63.6 6.2 -85.1 -78.0 -84.4
1,3 Butadiene 47.6 5.0 89.9 5.0 'VA "21.9 -44.5
Test versus Control data: Negative (-) values = Reductions; Positive values =
Increases
In order to address various issues and advance the art, the entirety of this
disclosure
shows by way of illustration various embodiments in which the claimed
invention may
be practiced and provide for superior smoking articles. The advantages and
features of
the disclosure are of a representative sample of embodiments only, and are not
exhaustive and/or exclusive. They are presented only to assist in
understanding and
teach the claimed features. It is to be understood that advantages,
embodiments,
examples, functions, features, structures, and/or other aspects of the
disclosure are not
to be considered limitations on the disclosure as defined by the claims or
limitations on
ro equivalents to the claims, and that other embodiments may be utilised
and
modifications may be made without departing from the scope of the
disclosure. Various embodiments may suitably comprise, consist of, or consist
essentially of, various combinations of the disclosed elements, components,
features,
parts, steps, means, etc. In addition, the disclosure includes other
inventions not
presently claimed, but which may be claimed in future.
The foregoing description and examples have been set forth merely to
illustrate the
invention and are not intended to be limiting. Since modifications of the
described
embodiments incorporating the substance of the invention may occur to
persons skilled in the art, the invention should be construed broadly to
include all
2o variations within the scope of the appended claims and equivalents
thereof.
