Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Smoking Article
Technical Field
The invention relates to smoking articles and methods for making smoking
articles.
Background
Smoke produced when smoking articles, such as cigarettes, are combusted is
known to contain many different constituents. Smoking articles frequently
comprise a filter to remove constituents from the smoke that is drawn from the
smokeable material.
Summary
According to a first aspect, a method of making a smoking article is provided.
In
use, the smoking article generates smoke having a smoke constituent. The
smoking article comprises a smoke constituent reducing technology which is
capable of reducing the concentration of the smoke constituent. The method
comprises:
1) determining one or more first lateral regions at which, when the
smoking article is in use, the smoke constituent is present at a first
concentration, and one or more second lateral regions at which, when the
smoking article is in use, the smoke constituent is present at a second
concentration which is lower than the first concentration; and,
2) producing a smoking article in which the smoke constituent reducing
technology is targeted to reduce the concentration of the smoke constituent
present at the one or more first lateral regions.
According to a second aspect, a method of reducing the concentration of a
smoke
constituent in the smoke produced by a smoking article is provided. The
smoking
article comprises a smoke constituent reducing technology which is capable of
reducing the concentration of the smoke constituent in smoke. The method
comprises:
1) determining one or more first lateral regions at which, when the
smoking article is in use, the smoke constituent is present at a first
concentration, and one or more second lateral regions at which, when the
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smoking article is in use, the smoke constituent is present at a second
concentration which is lower than the first concentration; and,
2) producing a smoking article in which the smoke constituent reducing
technology is targeted to reduce the concentration of the smoke constituent
present at the one or more first lateral regions.
The smoke constituent reducing technology may be located in the one or more
first lateral regions.
The smoke constituent reducing technology may or may not also be located in
the one or more second lateral regions.
The amount of smoke constituent reducing technology located in the one or more
first lateral regions may be greater than the amount located in the one or
more
second lateral regions.
The smoke constituent reducing technology may be included in any suitably
appropriate amount sufficient to ensure that the concentration of the target
smoke constituent in smoke is reduced. For example, the relative amounts of
smoke constituent reducing technology located in the first and second regions
may be proportional to the relative first and second concentrations of the
smoke
constituent. In other embodiments, the relative amounts of smoke constituent
reducing technology and concentrations of the smoke constituent may not be
proportional.
The smoking article may comprise a rod of smokeable material, and in this
case,
the first and second lateral regions may be regions of the rod of smokeable
material.
The rod of smokeable material may be generally cylindrical in shape and in
this
case, the first and second lateral regions may be located on a diametrical
line
across the width of the cylinder.
The smoke reducing technology may be located at the one or more first and/or
second lateral regions. In addition, or alternatively, the smoke reducing
technology may be located in a region of the smoking article which is away
from
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the one or more first and/or second lateral regions. For example, the smoking
article may comprise a filter and in this case, the smoke constituent reducing
technology may be located within the filter to reduce the concentration of the
smoke constituent present at the one or more first lateral regions. The filter
may
comprise a smoke reducing technology to reduce the concentration of the smoke
constituent generated at the one or more first lateral regions. In addition,
or
alternatively, the filter may contain a plurality of smoke reducing
technologies,
targeted to reduce concentrations of the smoke constituent or smoke
constituents generated in both the first and second lateral regions.
The rod of smokeable material and/or the smoking article filter may comprise
portions of varying density to create controlled pressure drop regions to
control
airflow through the smoking article.
The smoking article may comprise a plurality of different smoke constituent
reducing technologies. For example, there may be two different smoke
constituent reducing technologies included in the smoking article. In this
case,
the two different smoke constituent reducing technologies may be located in
the
same one or more first lateral regions. Alternatively, the two different smoke
constituent reducing technologies may be located in different lateral regions,
which may include the first and/or second lateral regions, and/or alternative
regions.
For example, it may be desirable to reduce smoke constituent levels in both
the
one or more first and second lateral regions. To achieve this, smoke
constituent
reducing technologies, which may be the same or different technologies, may be
included at the one or more second lateral regions in addition to the one or
more
first lateral regions.
The plurality of different smoke constituent reducing technologies may be
directed towards the same or different smoke constituents.
The smoking article may comprise a co-axial rod comprising an outer rod of
smokeable material circumscribed by an outer wrapper, the outer rod comprising
an inner rod of smokeable material circumscribed by an inner wrapper.
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The inner wrapper may be permeable or impermeable to the passage of smoke
constituents.
The inner wrapper may comprise the smoke constituent reducing technology.
The smokeable material of the inner and / or outer rod may comprise the smoke
constituent reducing technology.
The outer wrapper may be permeable or impermeable to the passage of smoke
constituents.
The outer wrapper may comprise the smoke constituent reducing technology.
The inner and/or outer rods may be wrapped in a plurality of wrappers, one or
more of which may comprise the smoke constituent reducing technology. For
example, particulate sorbent material may be adhered to one or more surfaces
of
one or more of the wrappers. The particulate sorbent material may cover the
entire surface or surfaces, or may be present in one or more discrete patches
on
the surface or surfaces of the one or more wrappers. In addition, or
alternatively,
particulate sorbent material may be present within the structure of the
wrapper
material itself.
One of the inner or outer rods may have a higher density relative to the other
rod
to create a region of controlled pressure drop to control airflow through the
smoking article.
The inner rod may comprise a further inner rod of smokeable material
circumscribed by a further inner wrapper, thus forming a triple core co-axial
rod.
The smoking article may comprise a thread. For example, the smoking article
may comprise a rod of smokeable material and the thread may extend
continuously within the smokeable material along the whole length of the rod
of
smokeable material.
The smoking article may comprise a plurality of threads, such as 2, 3, 4, 5,
6, or
more threads.
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The thread or threads may extend along the rod of smokeable material in one or
more lateral regions corresponding to the one or more first lateral regions at
which, when the smoking article is in use, the target smoke constituent has
been
5 found to occur in a higher concentration.
The smoking article may comprise particles that may be concentrated in a
longitudinal region extending along the rod of smokeable material.
The smoking article may comprise a plurality of lateral regions in which
particulate material is concentrated, such as 2, 3, 4, 5, 6, or more regions.
The region or regions of particulate material may extend along the rod of
smokeable material in one or more lateral regions corresponding to the one or
more first lateral regions at which, when the smoking article is in use, the
target
smoke constituent has been found to occur in a higher concentration.
The smoking article may comprise both a thread and longitudinally disposed
granular material in the same or different one or more lateral regions,
targeted
to the same or to different smoke constituents.
The smokeable material may be circumscribed by a wrapper and the particles
may be adhered to the inner surface of the wrapper.
The smokeable material may be circumscribed by a plurality of wrappers, one or
more of which may comprise the smoke constituent reducing technology. For
example, particulate sorbent material may be adhered to one or more surfaces
of
one or more of the wrappers, covering the entire surface or surfaces, or
present
in one or more discrete patches on the surface or surfaces. In addition, or
alternatively, particulate sorbent material may be present within the
structure of
the wrapper material itself.
The smoke constituent reducing technology may be in particulate or granular
form.
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The smoke constituent reducing technology may comprise an additive. The
additive may be a sorbent or a catalyst.
The smoke constituent reducing technology may comprise a diluent.
The smoke constituent reducing technology may comprise a smokeable material
which in use generates a concentration of the smoke constituent which is lower
than the concentration that is produced by tobacco.
According to a third aspect, a smoking article is provided. In use, the
smoking
article generates smoke having a smoke constituent. The smoking article
comprises a smoke constituent reducing technology which is capable of reducing
the concentration of the smoke constituent. In use, the smoke constituent is
present at a first concentration in one or more first lateral regions of the
smoking article. The smoke constituent is present at a second concentration
which is lower than the first concentration in one or more second lateral
regions
of the smoking article. The smoke constituent reducing technology is targeted
to
reduce the concentration of the smoke constituent present at the one or more
first lateral regions.
The smoke constituent reducing technology may be located at the one or more
first lateral regions.
The smoke constituent reducing technology may additionally be positioned at
the
one or more second lateral regions.
The amount of smoke constituent reducing technology located in the one or more
first lateral regions may be greater than the amount located in the one or
more
second lateral regions.
The smoking article may comprise a rod of smokeable material, and in this
case,
the first and second lateral regions may be regions of the rod of smokeable
material.
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The rod of smokeable material may be generally cylindrical in shape and in
this
case, the first and second lateral regions may be located on a diametrical
line
across the width of the cylinder.
According to a fourth aspect, a smoking article, which is obtainable by the
method of the first aspect, is provided.
Brief Description of Drawings
Preferred embodiments of the present invention will now be described with
reference to the accompanying drawings (not to scale), in which:
Figure la is a perspective view of a smoking article according to one aspect
of the
present invention, showing in particular the co-axial construction of the rod
of
smokeable material, wherein the inner wrapper comprises a smoke constituent
reducing additive;
Figure lb is transverse cross-sectional view of the body of the co-axial
smoking
article of Figure la, showing in particular, the inner wrapper comprising a
smoke
constituent reducing additive targeted to a lateral region of the rod of
smokeable
material;
Figure 2 a is a perspective view of a smoking article according to one aspect
of the
present invention, showing in particular, a thread comprising a smoke
constituent reducing additive located along a longitudinal axis of a rod of
smokeable material;
Figure 2b is transverse cross-sectional view of the body of the smoking
article of
Figure 2 a, showing in particular, a thread comprising a smoke constituent
reducing additive targeted to a central lateral region of the rod of smokeable
material;
Figure 3a is a perspective view of a smoking article according to one aspect
of the
present invention, showing in particular, particulate smoke constituent
reducing
additive located along a longitudinal axis of a rod of smokeable material;
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Figure 3h is transverse cross-sectional view of the body of the smoking
article of
Figure 3a, showing in particular, particulate smoke constituent reducing
additive
targeted to a central lateral region of the rod of smokeable material;
Figure 4 shows a number of graphs illustrating gas concentration profiles
(%v/v)
along the central axis of a cigarette; and,
Figures 5-10 show gas concentration (%v/v) and temperature distributions in a
smoking article at different time points.
Detailed Description
As used herein, the term "smoking article" includes smokeable products such as
cigarettes, cigars and cigarillos whether based on tobacco, tobacco
derivatives,
expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-
not-burn products and other devices capable of generating and delivering an
aerosol. Such smoking articles may be provided with a filter.
As used herein, the term "smoke constituent" includes any compound that may
be found in the smoke produced by the combustion and/or pyrolysis of tobacco.
The smoke arising from a smoking article comprising tobacco is a complex,
dynamic mixture of more than 5000 identified compounds. The constituents are
present in the mainstream smoke (MS), which exits the mouth end of the
cigarette, and are also released between puffs as constituents of sidestream
smoke (SS).
Smoking articles such as cigarettes and their formats are often named
according
to the cigarette length: "regular" (typically in the range 68 -75 mm, e.g.
from
about 68 mm to about 72 mm), "short" or "mini" (68 mm or less), "king-size"
(typically in the range 75 - 9imm, e.g. from about 79 mm to about 88 mm),
"long" or "super-king" (typically in the range 91-105 mm, e.g. from about 94
mm
to about 101 mm) and "ultra-long" (typically in the range from about no mm to
about 121 Mal).
Cigarettes are also named according to their circumference: "regular" (about
23-
25 mm), "wide" (greater than 25 mm), "slim" (about 22-23 mm), "demi-slim"
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(about 19-22 mm), "super-slim" (about 16-19 mm), and "micro-slim" (less than
about 16 mm). Accordingly, a cigarette in a king-size, super-slim format will,
for example, have a length of about 83 mm and a circumference of about 17 mm.
Cigarettes in the regular, king-size format, namely with a circumference of
from
23 to 25 mm and an overall length of from 75 to 91 mm, are one of many formats
commercially manufactured.
Smoking articles may be manufactured in any of the above formats. The
smoking article can, for instance, be from 70 to womm in length and from 14 to
25mm in circumference. Indeed, the smoking article may have any suitable size
and shape as appropriate.
When a smoking article comprising a rod of smokeable material is in use,
combustion and/or pyrolysis of the smokeable material may cause the
production of a number of smoke constituents. The concentration at which
smoke constituents occur within the burning coal (the burning tip of the
cigarette) may differ when the smoking article is used under smouldering
versus
puffing conditions.
When a smoking article is in use the burning portion (burning coal) advances
along the rod of smokable material. By inserting a miniature or micro-sampling
probe into the smoking article in use, aerosol samples may be withdrawn
without
influencing the smoking, combustion, and/or pyrolysis processes occurring. In
this way, the concentration of a particular smoke constituent at a specific
location relative to the burning portion may be determined. By repeating this
process using the probe to investigate different specific locations within the
smoking article, a map of the concentration of the smoke constituent within
the
smoking article as it is used may be produced. The concentration of the smoke
constituent may be determined as a function of smoking parameters such as the
puff volume, puff length, and inter-puff duration. Measurements may be
effected
relative to a fixed position on the cigarette, such as the burn line.
The concentration of smoke constituents has been found to differ in different
lateral regions across the rod of smokeable material. Regions of higher and
lower
concentration may be located on a diametrical line across the width of the
cylindrical rod of smokeable material.
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As used herein, the "lateral" dimension of a smoking article or a rod of
smokeable material refers to any diametric line across the width of a
cylindrical
rod of smokeable material, wherein the width is measured perpendicularly to
the
5 longitudinal axis of the rod.
Inclusion of smoke constituent reducing technology
In accordance with the disclosed method, in order to reduce the concentration
of
a particular smoke constituent in the smoke produced by a smoking article, the
10 skilled person must first determine the concentration of the smoke
constituent at
different positions within the smoking article when the smoking article is in
use.
A smoke constituent reducing technology, which is capable of reducing the
concentration of the smoke constituent of interest, may then be incorporated
within the smoking article, targeted to reduce the concentration of the smoke
constituent at the location at which the smoke constituent has been found to
be
present at a higher concentration.
This approach has a number of advantages over previous approaches to reducing
the concentration of smoke constituents in smoke. By targeting the location of
highest concentration, the greatest effect on the concentration of the
constituent
of interest within the smoke may be most effectively achieved. Moreover, the
amount of smoke constituent reducing technology may be reduced because a
lower amount of the technology may be used in areas in which the constituent
is
produced in the lowest concentration, albeit optionally at an inclusion level
that
effectively reduces the concentration of the smoke constituent in that
location.
Also, smoke constituent reducing technologies, which are more effective at
reducing a particular smoke constituent, or classes of constituents, in the
aerosol, may be selected and positioned within the smoking article to target
these constituents. For example, the smoke constituent reducing technologies
may be positioned in the region of formation of the smoke constituent.
Positioning a smoke constituent reducing technology within the 'hot zones' of
combustion and/or pyrolysis in the smoking article may be kinetically
favourable
to smoke constituent reducing technologies such as catalysts. The
effectiveness
of sorbents could also be enhanced in the hot zone, since a target smoke
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constituent, whilst in the solid or liquid phase at lower temperatures, may
occur
in the gaseous phase within this zone, and thus be more readily adsorbed. Such
technologies, which demonstrate enhanced activity at elevated temperatures,
may advantageously be targeted to the hot zones to enhance the removal or
destruction of the target smoke constituents.
Conversely, other smoke constituent reducing technologies may operate more
effectively at lower temperatures and thus may advantageously be targeted to
cooler areas of the smoking article, such as the filter tip.
Since the burning portion advances along the rod as the smoking article is
used,
the lateral region at which the smoke constituent occurs at a higher
concentration will therefore also advance along the rod of smokeable material.
Thus, to optimally target the particular smoke constituent, a smoke
constituent
reducing technology may be incorporated longitudinally throughout the length
of
the smoking article at a particular lateral region.
The smoke constituent reducing technology may be incorporated within the rod
of smokeable material and/or the filter as appropriate. The smoke constituent
reducing technology is targeted to reduce the concentration of a particular
smoke constituent at a lateral position corresponding to a position in which
the
smoke constituent is found in a higher concentration.
The smoke constituent reducing technology may be included in the smoking
article at the one or more lateral regions at which the smoke constituent has
been found to be produced at a higher concentration. The smoke constituent
reducing technology may optionally also be included in a lower amount in a
lateral region at which the smoke constituent is produced at a lower
concentration.
Location of the smoke constituent reducing technology
The smoke constituent reducing technology may be incorporated within the rod
of smokeable material and/or the filter as appropriate.
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The smoke constituent reducing technology may be located at the one or more
first lateral regions at which, in use, the smoke constituent has been found
to be
present at a higher concentration, relative to the concentration at another
region
of the smoking article.
The smoke constituent reducing technology may be located in a greater amount
at a first lateral region at which, in use, the smoke constituent has been
found to
be present at a higher concentration, and, in a lesser amount, at a second
lateral
region at which, in use, the smoke constituent has been found to be present at
a
lower concentration.
The smoke reducing technology may be located in a region of the smoking
article
which is away from the one or more first lateral regions at which, in use, the
smoke constituent has been found to be present at a higher concentration. In
this case, the smoke constituent reducing technology may be targeted to reduce
the concentration of the smoke constituent at the one or more first lateral
regions at which, in use, the smoke constituent has been found to be present
at a
higher concentration, relative to the concentration at another region of the
smoking article.
The smoke reducing technology may be located in a region of the smoking
article
which is away from the one or more second lateral regions at which, in use,
the
smoke constituent has been found to be present at a lower concentration.
Several different smoke reducing technologies may be used in a smoking
article,
positioned in the same or different lateral regions.
It has now been discovered that the incorporation of smoke constituent
reducing
technologies longitudinally in different lateral positions within a smoking
article
reduces the level of target smoke constituents generated in use in the smoke.
Depending on the particular smoke constituent reducing technology, the
technology may be included in the rod of smokeable material, in the smoking
article filter, or in both the rod of smokeable material and the smoking
article
filter.
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A number of smoke constituent reducing technologies may only be suitable for
incorporation into the filter of the smoking article. Porous polymer resins
have
been designed for trapping volatile and semivolatile substances from air, for
example Tenax TA . Other sorbent polymeric resins are available, for example,
molecularly imprinted polymers, and commonly used ion exchange or chelating
resins, such as Diailon CR-20. These materials are unsuitable for use within
the
smoking material, due to their thermal instability and potential degradation
in
the 'hot zone' of the smoking article.
Smoke constituents
In some embodiments, reductions in mainstream smoke constituents may
include, but are not restricted to, one or more of the substances known in the
art
as 'Hoffmann analytes'. This term relates to a group of constituents of
mainstream smoke generated from a smoking article, and includes: aromatic
amines; phenols; carbonyls; polycyclic aromatic hydrocarbons; acrylonitrile;
volatile hydrocarbons such as isoprene, styrene, benzene, and 1,3-butadiene;
nitrogen heterocyclics such as pyridine; quinoline; tobacco specific
nitrosamines
(TSNAs) such as N'- nitrosoanabasine (NAB), N'- nitrosoanatabine (NAT), 4-
(methylnitrosamino)-1-(3-pyridy1)-1-butanone (NNK) and N'- nitrosonornicotine
(NNN); inorganic compounds such as ammonia, hydrogen cyanide, nitric oxide
and carbon monoxide; and heavy metals such as mercury, cadmium, lead,
chromium and nickel.
The smoke constituents targeted by the smoke constituent reducing technology
may include, but are not restricted to, one or a combination of: aromatic
amines, such as i-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, 4-
aminobiphenyl; phenols, such as phenol, o-cresol, m-cresol, p-cresol,
catechol,
resorcinol, hydroquinone; carbonyls, such as formaldehyde, acetaldehyde,
acetone, acrolein, propionaldehyde, crotonaldehyde, methyl ethyl ketone,
butyraldehyde; polycyclic aromatic hydrocarbons such as benzo(a)pyrene,
naphthalene; aromatic hydrocarbons such as, toluene, benzene; acrylonitrile;
volatile hydrocarbons such as isoprene, styrene and 1,3-butadiene; nitrogen
heterocyclics such as pyridine, quinoline; tobacco specific nitrosamines
(TSNAs)
such as N'- nitrosoanabasine (NAB), N'- nitrosoanatabine (NAT), 4-
(methylnitrosamino)-1-(3-pyridy1)-1-butanone (NNK) and N'- nitrosonornicotine
(NNN); inorganic compounds such as ammonia, hydrogen cyanide, nitric oxide
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and carbon monoxide; and heavy metals such as mercury, cadmium, lead,
chromium and nickel.
Smoke constituent reducing technologies
The smoke constituent reducing technology may comprise any technology that is
capable of being incorporated into a smoking article and reducing the
concentration of a constituent of the smoke produced in use by the smoking
article. The smoke constituent reducing technology may be specific for a
particular smoke constituent. Alternatively, the smoke constituent reducing
technology may have a broad capacity to interact with various smoke
constituents or classes of smoke constituents.
The smoke constituent reducing technology may comprise any technology that is
capable of reducing the concentration of a smoke constituent in smoke. For
example, the smoke constituent reducing technology may comprise an additive,
such as a sorbent or a catalyst, a diluent, or a modified or synthetic
smokeable
material. By way of examples, a number of suitable smoke constituent reducing
technologies are discussed below.
Additives
The smoke constituent reducing technology may be a smoke constituent reducing
additive. The smoke constituent reducing additive may be any additive that is
capable of reducing the concentration of a smoke constituent in smoke. For
example, the smoke constituent reducing additive may comprise a sorbent or a
catalyst.
The additive may be in any suitable form. For example, the additive may be
particulate or in a processed form, such as in the form of a monolith.
The smoke constituent reducing technology may be a particulate additive, the
particles of which are concentrated in one or more longitudinally extending
regions within the filter material or the rod of smokeable material.
The smoke constituent reducing technology may be an additive which is
incorporated into one or more of the paper wrappers of the smoking article.
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The additive may be adhered to one or more surfaces of one or more of the
wrappers. The additive may cover the entire surface of one side of the
wrapper,
or the entire surface of both sides of the wrapper. Alternatively, the
additive may
be present in one or more discrete patches on the wrapper, which may be on one
5 side of the wrapper, or on both sides of the wrapper. The one or more
patch or
patches may have any shape or configuration. For example, the patch or patches
may be in the form of circumferential bands around the smoking article, or
longitudinal stripes along the length of the smoking article. Such wrappers
are
discussed, for example, in WO 2007/104908.
In addition, or alternatively, particulate additive material may be present
within
the structure of the wrapper material itself, as described, for example, in WO
2010/043475. For example, the additive may be a particulate sorbent material
such as active carbon which is incorporated into the structure of the paper
during manufacture of the paper. The sorbent may carry a further smoke
constituent reducing technology, for example, the sorbent may be impregnated
with a diluent, and/or the sorbent may serve as a carrier for a catalyst.
The wrapper material may be a paper material. Alternatively, the wrapper may
comprise a reconstituted tobacco material. The reconstituted tobacco material
may comprise particulate additive material. The additive may be applied to the
reconstituted tobacco material using the same approaches as described above in
respect of paper wrappers. For example, the additive may be applied to the
surface of the material, and/or the additive may be incorporated within the
structure of the reconstituted tobacco material itself. Such a material is
described, for example, in WO 99/38396.
The additive may be adhered to one or more threads which extend longitudinally
along the length of the smoking article filter and/or rod of smokeable
material.
Such threads are described, for example, in WO 96/14762, WO 2009/010380,
and WO 2010/032032.
The smoke constituent reducing additive may be coated or otherwise contained
in a protective environment to prolong shelf life. For example, the smoke
constituent reducing additive may comprise an encapsulated additive. The
protective environment utilised to prolong shelf life of the smoke constituent
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reducing additive should not inhibit the activity of the material, which may
be
capable of being released or activated by mechanisms encountered during the
smoking process. For example, the additive may be activated by heat or by
interaction with a smoke constituent such as water.
Sorb ents
A "sorbent" is a substance that can condense or hold molecules of other
substances on its surface, and/or can take up other substances, i.e., through
penetration of the other substances into its inner structure, or into its
pores.
Accordingly, the term "sorbent" as used herein refers to an adsorbent, an
absorbent, or a substance that can function as both an adsorbent and an
absorbent. The sorbent may be any relatively high surface area material to
which
the smoke constituent may adsorb, and which is thereby capable of reducing the
concentration of a smoke constituent in smoke.
The smoke constituent reducing additive may include one or a combination of
any suitable sorbents, including, for example, carbon (such as activated
carbon),
zeolite, silica gel, silica, silicates, alumino-silicates, sepiolite, clay,
aluminium
oxide.
In particular, the smoke constituent reducing additive may be an activated
carbon material. The activated carbon material may be derived from vegetable
matter (such as coconut shells), as described, for example, in WO 2012/032349.
Alternatively, the activated carbon material may be derived from a resin (such
as
a phenolic resin), for example, as described in WO 2006/103404.
The activated carbon material may be surface modified to improve the
specificity
of the material for a particular smoke constituent or class of smoke
constituents.
The presence of particular chemical groups on the surface of the porous carbon
material may affect the adsorption properties of the material. For example,
activated carbon material prepared using a nitrogen-donating agent may
enhance the selective adsorption of smoke constituents including low molecular
weight aldehydes and HCN, as described in WO 2012/098405. Likewise,
activated carbon material prepared using magnesium carbonate may enhance the
selective adsorption of acrolein, formaldehyde and HCN, as described in WO
2012/160354. The hydrophobicity and/or hydrophilicity of the surface of the
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sorbent material may be modified to provide further control of the sorbent
properties and improve the specificity of the material for a particular smoke
constituent or class of smoke constituents.
The sorbent may comprise micropores (<2nm pore diameter), mesopores (2-
5onm diameter), and/or macropores (diameters greater than 5onm). The
sorbent may be modified to adjust the pore structure, such as to increase the
mesoporosity, as described, for example, in WO 2010/103323 and WO
2012/032349.
The sorbent may be present in the smoking article in granular or particulate
form, for example, as described in WO 2006/103404.
The sorbent may be a carbonaceous dried gel, for example of the type described
in WO 2011/030151. Such dried gels are porous, solid-state materials obtained
from gels or sol-gels whose liquid component has been removed and replaced
with a gas, which have then been pyrolysed and/or carbonized. They can be
classified according to the manner of drying and include carbon xerogels,
aerogels and cryogels.
Xerogels are typically formed using an evaporative drying stage under ambient
pressure conditions. They generally have a monolithic internal structure,
resembling a rigid, low density foam having, for example, 60-90 % air by
volume. Aerogels, on the other hand, can be produced using other methods such
as supercritical drying. They contract less than xerogels during the drying
stage
and so tend to have an even lower density (90-99 % air by volume for example).
Cryogels may be produced using freeze drying techniques.
The sorbent may comprise carbon material in the form of carbon nanotubes
and/or graphene.
The sorbent may comprise a Metal Organic Framework (MOF).
The sorbent may be coated. For example, the sorbent may comprise an alginate-
coated porous carbon material. In addition, or alternatively, the sorbent may
carry a diluent, for example as described in WO 2010/125386.
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The sorbent may be in a processed form. In particular, the sorbent may be in
the
form of a monolith, for example as described in WO 2012/168699.
The sorbent may comprise an adsorption promoter. A suitable adsorption
promoter may comprise a hydrophilic organic substance and both a hydrogen
bond donor and acceptor. Such an adsorption promoter may increase the affinity
of the sorbent for phenol, as discussed in WO 2011/015861.
Catalysts
The smoke constituent reducing additive may be a catalyst. A "catalyst" is a
substance that modifies and increases the rate of a chemical reaction without
being consumed in the process. The catalyst may be capable of promoting the
conversion of a smoke constituent into one or more different substances. In
addition, or alternatively, the catalyst may convert a compound, which would
otherwise be a precursor of the target smoke constituent, into an alternative
compound, thus preventing the formation of the smoke constituent.
Catalysts may comprise, for example, metals, such as transition metals or rare
earth metals, metal salts, or metal oxides. In some embodiments, a catalyst
capable of facilitating the oxidation of CO to CO2 may be used. Suitable CO
catalysts include metals, such as transition metals or rare earth metals,
metal
salts, metal oxides or combinations thereof. In particular, a catalyst capable
of
facilitating the oxidation of CO to CO2 may comprise iron oxide and/or a
hopcalite (copper manganese oxide).
The catalyst may be placed on a support or carrier made of graphite, activated
carbon, copper oxide, alumina or titania, for example. The carrier may be
uniformly coated with the catalyst, the loading being from about 0.1% to about
10%, based on the total dry weight of the coated support or carrier.
The catalyst may be provided in the form of coarse, fine or ultrafine
particles.
Coarse particles are particles having a diameter of about 2.5[Im to about
200[Im.
Fine particles are particles having a diameter of about ioonm to about
Ultrafine particles are particles having a diameter of less than about loonm.
Typically, the particles have an average particle size of between about inm
and
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100[1m, for example, between about ionm to about io[tm. Particles of catalyst
may be obtained commercially.
Molecularly imprinted polymers
The additive may comprise a molecularly imprinted polymer (MIP).
The MIP may be specific for one or more than smoke constituents. For example
the MIP may be capable of specifically binding tobacco specific nitrosamines,
as
described, for example, in WO 2008/068153.
Diluents
The smoke constituent reducing technology may comprise a diluent. A "diluent"
acts as a direct replacement of a smoke constituent, and thereby reduces the
concentration of the smoke constituent in the smoke.
The diluent may be included in the smokeable material. For example, the
diluent
may be bound to the smokeable material and/or incorporated within the cellular
structure of the material, as described in WO 03/092416 and WO 2012/010880.
The diluent may be incorporated into the wrapper of the smokeable material.
For
example, the diluent may be carried by a sorbent material which is
incorporated
into the wrapper. Such wrappers are described, for example, in WO
2010/043475.
The diluent may be impregnated into particulate porous material, as described,
for example, in WO 2010/125386.
The diluent may be in the form of particles of diluent encapsulated with a
barrier
material, as discussed, for example, in WO 2010/125385.
Suitable diluents include aerosol forming means utilising a wide range of
classes
of substances known to those skilled in the art. For example, polyhydric
alcohols,
such as glycerol, propylene glycol, sorbitol and triethylene glycol; esters,
such as
diacetin, triethyl citrate, isopropyl myristate or triacetin, high boiling
point
hydrocarbons, or lactic acid. A combination of diluents may be used, in equal
or
differing proportions.
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Other additives
The smoke constituent reducing technology may comprise a chemical reactant
which may reduce the concentration of a smoke constituent by reacting with the
5 constituent. The reaction mechanism may comprise a chemical combination
and/or a chemical combination followed by a decomposition.
The smoke constituent reducing technology may comprise an additive which
adjusts the temperature of combustion of the smokeable material.
For example, the additive may act to either decrease the thermal energy
produced during the smoking process by passively absorbing energy, or it may
actively influence smoking thermal energy by itself undergoing an endothermic
promoted change (wherein thermal energy may be taken out of the smoking
process) or an exothermic promoted change (wherein thermal energy may be
contributed to the smoking process). In this way, due to the adjusted
temperature, the chemical reactions occurring as the smokeable material
combusts or pyrolyses may be adjusted, and different smoke constituents may be
produced, and as a result, the concentration of target smoke constituents, or
classes of constituents, may be reduced.
An example of a material that may be used to increase the temperature is a
carbon material such as particulate charcoal material.
Similarly, other additives may be used to change the conditions within the
smokeable material and thus adjust the chemical reactions occurring. Suitable
examples may include oxidising and reducing agents.
Ceramic wrapper materials
The smoke constituent reducing technology may comprise a ceramic-based
wrapper. The ceramic-based wrapper may be capable of trapping smoke
constituents. In addition, or alternatively, the ceramic-based wrapper may be
thicker than a conventional wrapper and thus displace a proportion of the
smokeable material. Ceramic-based wrappers are discussed, for example, in WO
01/41590.
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The ceramic-based wrapper may comprise a smoke constituent reducing additive
which is capable of reducing the concentration of a smoke constituent in
smoke.
The additive may be incorporated together with the ceramic filler into the
structure of the wrapper. In addition, or alternatively, the additive may be
applied to the surface of the wrapper.
The ceramic-based wrapper may comprise a proportion of a ceramic filler of
predefined shape, a binder, optionally a burn additive and optionally an ash
improver.
The predefined shape of the ceramic filler is such that the wrapper has a
porous
self-sustaining structure and when combusted the wrapper loses its structural
integrity. For example, the ceramic filler may be spherical or substantially
spherical, oval or substantially oval, or another irregular shape
approximating
thereto.
Advantageously the ceramic filler has a particle size in the range of 2-9o[tm,
more preferably 2-75[Im and even more preferably 25-7o[tm, such as about
5o[tm.
The ceramic filler may be an insoluble or low solubility metal oxide or metal
salt,
and may be a thermally stable metal oxide or metal salt. The ceramic filler
may
be one or more of alumina, silica, an alumino-silicate, silicon carbide,
stabilised
or un-stabilised zirconium oxide, zircon, garnet, feldspar, or other materials
known to the skilled man and having the necessary particle size or other
suitable
ceramic materials having been milled to the necessary size or shape.
The ceramic filler may be present at greater than 40% by weight of the dry
materials in the slurry producing the wrapper, and is more preferably present
in
the range of 50-95%, and more preferably 70-90%.
The binder functions to cement the particles of ceramic filler together. The
binder may be an organic binder, and may be one or more of an alginate, (such
as calcium alginate or propylene glycol alginate), a gum, a cellulose
(modified or
natural), a pectin or pectinaceous binder, starch, or the Group I or II metal
salts
of these binders, such as sodium carboxymethylcellulose or sodium alginate. In
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addition or alternatively, the binder may be an inorganic binder, and may be
one
or more of activated alumina, aluminium silicate, magnesium silicate or an
inert
clay.
A burn additive may be included in the ceramic-based wrapper to improve the
burn characteristics of the wrapper. The burn additive may be present in the
range of 1-15% by weight of the dry materials in the slurry used to produce
the
wrapper and is more preferably <10% and even more preferably <5%, such as in
the range of 2-5%. The burn additive is a burn promoter. Suitable burn
additives
may be selected from one or more of salts of Group I or II metals such as
acetates, citrates and other burn promoters known to the skilled person.
An ash improver may be included in the ceramic-based wrapper to provide
bridging means or packing improvement means between the ceramic filler
particles. The wrapper should burn down and ash in a manner similar to that of
a
conventional combustible smoking article. The components of the wrapper, and
in particular the ceramic filler and ash improver, have a particle size and/or
shape such that their combination provides the necessary strength in the
wrapper before combustion but loses such strength during combustion in order
to provide acceptable ashing of the combusted products.
The inorganic ash improver suitably has a platelet morphology and materials
that have the appropriate platelet morphology compared to the more rounded
shape of the ceramic filler, include one or more of mica, chalk, perlite,
clays,
such as, for example, vermiculite; kaolinites and talcs. The ash improver may
in
addition or alternatively be a material with a very small particle size such
that
particles thereof bridge the voids between the larger ceramic filler
particles.
In some embodiments, the ceramic-based wrapper may be produced using
known manufacturing techniques. In particular, ceramic-based wrappers may be
formed by producing a thick slurry of the wrapper components, coating the
slurry about a rotating mandrel, and removing excess moisture by physical or
chemical means. Alternatively, the slurry may be cast as a sheet on a drum or
band caster, or extruded as a hollow tube, through a "torpedo" die-head, for
example, which has a solid central section, or extruded as a sheet material.
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The ceramic-based wrapper may have a thickness of 0.1-4mm, and may
preferably be 1.5-3.5mm, such as 2.1-2.8mm in thickness.
Smokeable materials
The smoke constituent reducing technology may comprise the use of an
alternative or modified smokeable material. For example, some smokeable
materials may generate lower amounts of a smoke constituent than others and
the smoke constituent reducing technology may comprise a smokeable material
that is known to generate a low amount of a particular smoke constituent.
Thus,
a smokeable material that is known to generate a low amount of a smoke
constituent may be incorporated into specific lateral regions of a rod of
smokeable material. Smokeable materials, including tobacco and tobacco
reconstituted materials, and tobacco-free materials, which generate low
amounts
of a smoke constituent, may be used.
The smoke constituent reducing technology may comprise a modified tobacco
material. The tobacco may be modified to reduce the amount of smoke
constituent produced upon combustion or pyrolysis of the tobacco. The tobacco
may be modified by addition of modifying agents. For example, salts such as
inorganic salts may be added to tobacco to alter the type and concentrations
of
smoke constituents produced upon combustion or pyrolysis of the material.
Suitable metal salts include zinc chloride and magnesium chloride.
The tobacco may be modified by the addition of smoke diluents on its surface
and/or within its cellular structure, as described for example in WO
2012/010880. The tobacco may comprise a diluent and be coated with a barrier
material, as described for example, in WO 2010/125287.
The smoke constituent reducing technology may comprise a tobacco substitute
material such as a smokeable filler material. The smokeable filler material
may
comprise no tobacco, and may comprise for example, a filler such as chalk, and
a
binder. The smokeable filler material may be a foamed smokeable filler
material.
Such a material is described, for example, in WO 2005/044026.
The smoke constituent reducing technology may comprise a smokeable material
such as tobacco that is heated to cause the volatilisation of the low boiling
point
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components but avoiding pyrolysis or combustion of the material or volatiles,
and thereby reducing the concentration of smoke constituents.
Materials comprising no tobacco, such as chalk particles bound together with a
suitable binder such as sodium alginate to form a sheet or extrudate, which
may
be subsequently cut or shredded may also be used as a smoke constituent
reducing technology. These materials may also contain other ingredients which
act as aerosol forming substances that are released on combustion or by
thermal
means. Such sheets are described, for example, in WO 03/092416.
The smoke constituent reducing technology may be added to, and/or carried by,
a smokeable element comprising a porous material such as a porous carbon
material. The technology may be carried within the pores of the porous
material
and may be released or activated when the smoking article is in use. The
technology may be released by any suitable means, for example, the
temperature,
pH, moisture content, or other property of the smoke or combustion of the
smokeable material may induce the release and/or activation of the technology.
Such a material is described, for example, in WO 2013/045944.
Any of the smoke constituent reducing technologies may be used in combination
with another smokeable material, which may be another smoke constituent
reducing technology.
The smokable material may comprise tobacco material. The tobacco material
may comprise one or more of stem, lamina, and tobacco dust. The tobacco
material may comprise one or more of the following types: Virginia or flue-
cured
tobacco, Burley tobacco, Oriental tobacco, reconstituted tobacco, and expanded
tobacco. The smokable material may comprise a blend of tobacco material, and
may, for example, comprise Virginia tobacco, Burley tobacco, Oriental tobacco,
reconstituted tobacco, expanded tobacco, such as dry ice expanded tobacco, and
stem. The smokable material may comprise processed tobacco materials, such as
volume expanded or puffed tobacco, processed tobacco stems, such as cut-rolled
or cut-puffed stems, reconstituted tobacco materials, blends thereof, and the
like.
.35
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The smokable material may comprise a humectant. The humectant may
comprise, for example, glycerol, triethylene glycol and/or propylene glycol.
The smokable material may further comprise a colourant and/or a flavourant. As
5 used herein, the terms "flavour" and "flavourant" refer to materials
which, where
local regulations permit, may be used to create a desired taste or aroma in a
product for adult consumers. The colourant may be used to darken the material
and the flavourant may be used to impart a particular flavour. Finely ground,
granulated or homogenised tobacco may be used. Industry approved food
10 colourants may also be used, such as Ei50a (caramel), E151 (brilliant
black BN),
E153 vegetable carbon or E155 (brown HT). Suitable flavourants include
menthol and vanillin, for example.
Control of smoke flow
15 The smoking article may be configured such that different internal
regions offer
different levels of resistance to the passage of smoke, thereby providing
different
levels of pressure drop in the different regions. This may be achieved for
example, by the use of different smokeable materials, having different
inherent
densities, or different packing densities, in different regions of the smoking
20 article. In use, a greater pressure drop will be established as smoke is
drawn
through the region of higher density, as described, for example, in WO
2012/016795.
It may be advantageous to arrange smoking articles in this way because smoke
25 that is drawn through the region of greater pressure drop may move more
slowly
and therefore may be subject to an increased action from the smoke constituent
reducing technology within that region. This may be particularly effective in
embodiments in which the smoke constituent reducing technology comprises an
additive such as a sorbent or a catalyst.
Furthermore, different combinations of smoke constituents may be produced
under different pressures. Thus, the use of compartments having different
pressure drops may directly reduce the level of production of the smoke
constituent.
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Specific embodiments
A description of a suitable methodology to determine distribution
concentrations
of smoke constituents with respect to lateral and longitudinal regions of a
smoking article is given in the Examples.
The concentration of smoke constituents can be measured by inserting a
miniature or micro-sampling probe into the smoking article at known spatial
positions. Smoke samples may then be collected without influencing the
smoking, combustion, and/or pyrolysis processes that are occurring as the
smoking article is used. The concentration of smoke constituents may thus be
determined in real time, for example, by mass spectrometry as described in the
Examples.
Smoke constituents have been found to be produced at different concentrations
in different regions of the smoking article when the smoking article is in
use. In
accordance with the disclosed method, a smoke constituent reducing technology,
which is capable of reducing the concentration of the smoke constituent, is
targeted to reduce the concentration of the smoke constituent present at the
one
or more first lateral regions. For example, the smoke constituent reducing
technology may be incorporated within the smoking article at a lateral
position
corresponding to the location at which the smoke constituent has been found to
be present at a higher concentration relative to the concentration at another
lateral region.
The smoke constituent reducing technology may be incorporated into a smoking
article using any suitable method. A number of approaches, which have been
found to be suitable, are shown in the accompanying Figures and discussed
below.
Figure la, ib is a schematic illustration of a smoking article 101 according
to an
embodiment of the invention.
In the embodiment shown in Figure la, ib, the smoke constituent reducing
technology is targeted to a lateral region, which is an intermediate annular
region, located between the centre and the circumferential surface of the rod
of
smokeable material.
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Figure la, 1.13, shows a smoking article 101 comprising a filter 102 and a rod
of
smokeable material 103. The filter 102 is at the mouth end of the smoking
article 101. The rod of smokeable material 103 is in the form of a cylindrical
rod,
and the circumferential surface of the smokeable material 103 is wrapped in a
wrapping material 104, such as a cigarette paper.
The filter 102 comprises a substantially cylindrical plug of filter material
105
wrapped in a plugwrap 106 around its circumferential surface. The wrapped rod
of smokeable material 103 is aligned with the filter 102, such that the end of
the
rod of smokeable material abuts the end of the filter 102. The rod of
smokeable
material 103 is joined to the filter 102 by tipping material 107 which
overlays
the filter 102 and partially overlays the wrapping material 104.
In the embodiment shown, the smoke constituent reducing technology 109 is
located within the rod of smokeable material 103. In other embodiments, a
smoke constituent reducing technology, which may be the same or a different
technology, may in addition or alternatively be located within the filter 102
of
the smoking article 101.
The rod of smokeable material 103 is of co-axial construction and has an inner
rod no, an inner wrapper 111, and an outer rod 112. The outer rod is wrapped
in
the wrapping material 104.
The inner rod no of the co-axial arrangement contains a first smokeable
material 114, which in the embodiment shown is cut tobacco material, and may
in general comprise any suitable smokeable material or blend.
The inner rod no is circumscribed by the inner wrapper 111, as shown in Figure
la, ib. The inner wrapper 111 is, in the present example, a cigarette paper.
The inner rod no and inner wrapper 111 are circumscribed by the outer rod 112,
as shown in Figure la, lb. In the embodiment shown, the outer rod 112
comprises a second smokeable material 115, comprising cut tobacco material,
which is combusted during use. The second smokeable material 115 may in
general comprise any suitable smokeable material or blend.
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As shown in Figure la, lb, the outer rod 112 is circumscribed by the outer
wrapper 104. In the embodiment shown, the outer wrapper 104 is a cigarette
paper.
The construction of the inner rod no, inner wrapper 111, outer rod 112 and
outer wrapper 104, may for example, be achieved through existing co-axial
cigarette manufacturing technology.
In use, combustion of the inner and outer rods 110, 112 generates smoke which
is drawn through the smoking article 101.
The rod of smokeable material comprises a smoke constituent reducing
technology 109 which is capable of reducing the concentration of a particular
target smoke constituent in smoke. In other embodiments, the smoke
constituent reducing technology may be capable of reducing the concentration
of
several target smoke constituents.
In the embodiment shown in Figure la, ib, the smoke constituent reducing
technology comprises particles of a smoke constituent reducing additive 109.
The additive 109 is capable of adsorbing a target smoke constituent from
smoke.
Specifically, the inner wrapper 111 comprises a smoke constituent reducing
additive 109, as shown in Figure lb. In this case, the additive is particulate
activated carbon material, and is adhered to, and completely covers, both
surfaces of the wrapper 111. Due to being adhered to the inner wrapper 111,
the
additive 109 is targeted to a position within the rod of smokeable material
103
corresponding to an intermediate annular region. The targeted region may be
varied by adjusting the position of the inner wrapper 111, for example, by
adjusting the relative diameters of the inner and outer rods 110, 112.
In the embodiment shown, the additive 109 is adhered to the wrapper 111 as
described in WO 2007/104908 and is present on both faces of the inner wrapper
111. Any suitable method may be used to apply the additive to the wrapper 111.
In other embodiments, the additive 109 may in addition, or alternatively, be
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incorporated within the structure of the wrapper 111, as described in WO
2010/043475.
The inner wrapper 111 is a paper wrapper material. In other embodiments,
however, the wrapper 111 may comprise an alternative material, such as a
reconstituted tobacco material, which may comprise particulate sorbent
material
as described in WO 99/38396.
By means of the arrangement shown in Figure 1, a smoke constituent reducing
additive may be targeted to specific lateral regions with the rod of smokeable
material 103. Specifically, the inner and outer rods 110, 112, may be
constructed
so that the inner wrapper 111 substantially coincides with the lateral regions
at
which a particular smoke constituent has been found to occur at a
concentration
which is higher than the concentration found in another lateral region.
In use, combustion of the rod of smokeable material 103 generates smoke which
is drawn through the smoking article 101. Due to the targeted positioning of
the
smoke constituent reducing additive 1439 within the smoking article 101, the
concentration in the smoke of a particular smoke constituent, which has
previously been found to be produced at a high concentration in the lateral
region of the smokeable material 1433 targeted by the inner wrapper 111, may
be
reduced.
In some embodiments, the inner wrapper 111 may comprise reconstituted
tobacco sheet material. The reconstituted tobacco sheet material may have a
similar thickness to a paper wrapper, or may be of a different thickness, such
as,
for example, thicker. In embodiments in which the wrapper is thicker than a
paper wrapper, the reconstituted tobacco sheet material 111 may function as a
smoke constituent reducing technology by displacing a proportion of the first
and/or second smokeable material 114, 115. In addition, or alternatively, due
to
the composition of the reconstituted tobacco sheet material 111, the material
may produce a reduced amount of the smoke constituent when combusted or
pyrolysed. For example, the reconstituted tobacco sheet material may comprise
a
sorbent, as described in WO 99/38396.
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The wrapper may also be modified in other ways in order to reduce the
concentration of a specific smoke constituent. For example, the wrapper may
comprise a diluent, as described in WO 2010/043475.
5 The inner rod wrapper 111 may be permeable to smoke and smoke
constituents,
or may be impermeable, and may prevent the passage of smoke and smoke
constituents.
In some embodiments, for example, where it is desired to target smoke
10 constituents in other lateral regions of the smoking article, the
smokeable
material of the inner rod 110 and/or outer rod 112 may comprise a smoke
constituent reducing technology.
For example, in some embodiments, in addition to, or as an alternative to
being
15 applied to one or more faces of the inner wrapper 111, or dispersed
throughout
the body of the wrapper material, the additive 109 may be applied to the
smokeable material 114, 115 of the inner and/or outer rod 110, 112. The
additive
may be bound to the smokeable material or simply distributed within the
smokeable material, for example, as described in WO 2011/033121. In these
20 embodiments, the inner wrapper 111 may serve to segregate lateral
regions of the
rod of smokeable material, wherein different lateral regions may comprise
different concentrations of additive 109.
In addition, or alternatively, the inner rod no and/or outer rod 112 may
25 comprise different smokeable materials or different blends of smokeable
material. Upon combustion, the different smokeable materials in the inner and
outer rods 110, 112, may give rise to different quantities of a particular
smoke
constituent. One or both of the smokeable materials 110, 112, may comprise a
smoke constituent reducing technology, which may be selected to produce a
30 lower concentration of the particular target smoke constituent. In
addition, or
alternatively, a smoke constituent reducing additive 109 may be applied to one
or both of the different smokeable materials.
For example, in some embodiments, the inner rod no may comprise one or
more tobacco substitute materials such as a smokeable filler material. Such
tobacco substitute materials may in use generate reduced levels of a target
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smoke constituent and may thereby constitute a tobacco constituent reducing
technology, which is targeted to a lateral region which is a central region of
the
smoking article, by means of the co-axial construction of the rod of smokeable
material.
In other embodiments, the outer rod 112 may in addition, or alternatively,
contain one or more tobacco substitute materials such as a smokeable filler
material. Such tobacco substitute materials may in use generate reduced levels
of
a target smoke constituent and may thereby constitute a tobacco constituent
reducing technology, which is targeted to a peripheral lateral region by means
of
the co-axial construction of the rod of smokeable material.
The smokeable filler materials that may be used in the inner rod no and/or
outer rod 112 may comprise an inorganic filler, such as described in WO
03/092416. The smokeable filler material may in addition, or alternatively, be
a
foamed smokeable filler material, such as described in WO 2005/044026.
The inner or outer rod 110, 112 may comprise a smokeable material other than
tobacco or a tobacco substitute material. For example, the smokeable material
of
the inner or outer rod 110, 112 may comprise a smokeable element. A suitable
smokeable element may comprise particles of a porous carrier material, bound
together by means of a binder, wherein the binder is a combustible binder. The
smokeable element may further comprise an agent, which may be a flavourant,
such as a tobacco extract, carried by the porous carrier material. Such a
smokeable element is described in WO 2013/045944.
In addition, or alternatively, the smoking article 101 may be arranged such
the
first or second smokeable material is heated to cause volatilisation of low
boiling
point components within the smokeable material, while avoiding pyrolysis or
combustion of the smokeable material or volatile smokeable material
constituents. Such an arrangement is described, for example in WO
2012/016795.
To improve the targeting of the smoke constituent reducing technology to the
one or more lateral regions at which the particular smoke constituent is
concentrated, the inner rod 110 may be symmetrical or asymmetrical. For
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example, in cross-section, the inner rod no may be circular, or may have any
non-circular shape, such as for example, oval, square, rectangular, or
triangular.
In addition, or alternatively, the inner rod no may be positioned off-centred
within the outer rod 112, such that the longitudinal axes of the two rods 110,
112
do not coincide.
In some embodiments, the inner rod no comprises one or more further inner
rod(s). In this way, smoke constituent reducing technologies can be targeted
towards an increased number of lateral locations within the smoking article.
In some embodiments, the smoking article is configured such that the inner and
outer rods 110, 112, offer different levels of resistance to the passage of
smoke.
Thus, there are different levels of pressure drop in the different
compartments.
This may be achieved for example, by constructing one of the inner and outer
rods at a higher density than the other rod. This will create a (greater)
pressure
drop in the rod of higher density. Smoke drawn through the compartment which
has a greater pressure drop may move more slowly and therefore may be subject
to an increased action from the smoke constituent reducing technology within
that compartment. This may be particularly effective in embodiments in which
the smoke constituent reducing technology comprises an additive such as a
sorbent or a catalyst.
Furthermore, different combinations of smoke constituents may be produced
under different pressures. Thus, the use of compartments having different
pressure drops may directly reduce the level of production of the smoke
constituent.
In some embodiments, the outer wrapper 104 may comprise the smoke
constituent reducing technology. This may be in addition, or as an
alternative, to
the use of a smoke constituent reducing technology in the first and/or second
smokeable materials 114, 115, and/or the inner wrapper 111. Such an
arrangement may be particularly suitable for targeting smoke constituents that
have been found to be produced at a higher concentration in peripheral
regions,
nearer to the circumferential surface of the outer wrapper 104 of the smoking
article 101.
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For example, the outer wrapper 1434 may comprise a smoke constituent reducing
technology in the form of an additive, such as a sorbent or a catalyst,
adhered to
the inner face of the wrapper 1434, such as described in WO 2007/104908. In
addition, or alternatively, the outer wrapper 104 may comprise reconstituted
tobacco sheet material, as described above in respect of the inner wrapper
111,
and in WO 99/38396.
In some embodiments the smoking article 101 may comprise a ceramic-based
wrapper, such as described in WO 01/41590. The ceramic-based wrapper may be
capable of trapping smoke constituents. In addition, or alternatively, the
ceramic-based wrapper may be thicker than a conventional wrapper and thus
displace or replace a proportion of the second smokeable material 115.
In some embodiments, the ceramic-based wrapper may comprise a smoke
constituent reducing additive which is capable of reducing the concentration
of a
smoke constituent in smoke. In some embodiments, the additive may be
incorporated together with the ceramic filler into the structure of the
wrapper. In
addition, or alternatively, the additive may be applied to the surface of the
wrapper 104.
In accordance with embodiments of the type shown in Figure la, lb, the
arrangement of two or more smoke constituent reducing technologies, which
may be the same or different technologies, at two or more lateral positions in
the
smoking article may be used to facilitate reductions of smoke constituents at
lateral positions where smoke constituents may be generated at both higher and
lower concentrations. Specifically, the arrangement of the co-axial smoking
article shown in Figure 1 allows the accurate incorporation of one or more
different smoke constituent reducing technologies into specific location(s) in
the
smoking article. For example, as described above, the inner and/or outer
wrappers 111, 1434, and/or the first and/or second smokeable material 114,
115,
or any combination of these parts, may comprise one or more smoke constituent
reducing technologies. The location of the technologies may be easily and
accurately controlled, by adjusting the materials used and the diameter of the
inner rod 1143, to target one or more smoke constituents based on prior
measurements of the concentration of the smoke constituents present at
different locations when the smoking article is in use.
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Figure 2a, 2b is a schematic illustration of a smoking article 201 according
to a
further embodiment of the invention. Corresponding reference numerals are
used for features of the smoking article 201 which are the same as those of
the
smoking article 101 described with reference to Figure 1, unless otherwise
stated
below.
As shown in Figure 2a, 2b the smoking article 201 includes a filter 202 and a
rod of smokeable material 203.
In the embodiment shown in Figure 2a, 2b, the smoke constituent reducing
technology is targeted to a lateral region, which is a central region of the
smoking article.
The filter 202 comprises a substantially cylindrical plug of filter material
205
wrapped in a plugwrap 2436 around its circumferential surface. The rod of
smokeable material 203 is wrapped in a wrapping material 204. The rod of
smokeable material 203 is connected longitudinally to the filter 202 by
tipping
material 207 overlaying the filter 202 and partially overlaying the wrapping
material 204.
The rod of smokeable material 203 is circumscribed by a wrapping material
204, as shown in Figure 2a, 2b. The wrapping material 204 may be a cigarette
paper. The rod of smokeable material 203 is connected longitudinally to the
filter 202 by tipping material overlaying the filter 202 and partially
overlaying
the wrapping material 204.
The rod of smokeable material 203 comprises a smokeable material, in this case
tobacco 2438. The smokeable material 2438 may in general comprise any suitable
smokeable material or blend.
The rod of smokeable material 203 also comprises a smoke constituent reducing
technology 209, which is capable of reducing the concentration of a smoke
constituent in smoke.
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In the embodiment shown, the tobacco rod 203 comprises a smoke constituent
reducing technology in the form of a thread 210 disposed within the tobacco
material 2438. The thread and its method of incorporation may be similar to
that
described in WO 96/14762 and WO 2010/032032.
5
The thread 210 is positioned along a central longitudinal axis of the rod 203.
The thread 210 extends continuously the whole length of the rod.
10 In the embodiment shown, the thread 210 comprises carbon in fibrous
form,
such as carbon fibre or carbonised fibre materials, for example, carbonised
polyester or polyamide, such as described in WO 96/14762.
The carbon fibre threads 210 are generally used as a continuous strand so as
to
15 be easily incorporable into the tobacco rod 203 as part of a continuous
manufacturing operation.
The thread 210 may comprise a loosely assembled bundle or strand of typically
1
to 30 micrometres diameter or larger.
The presence of the carbon fibre thread 210 may itself reduce the
concentration
of the smoke constituent, but the thread may also be used as a carrier, for
example of a smoke constituent reducing technology 209.
Any suitable smoke constituent reducing technology 209 may be carried by the
thread 210. For example, an additive 209 may be used, which may be a sorbent
such as, for example, particulate activated carbon material, or a catalyst
such as
a metal catalyst. Metals which are suitable for plating onto the thread 210
include, in successive layers, first copper then silver; copper then gold;
copper,
silver then gold; copper, silver then platinum; copper, silver, gold then
platinum
or other suitable metals such as tin. Any other suitable metal or combination
of
metals may be used.
The additive 209 may be applied to the thread 210 by any suitable method. The
smoke constituent reducing technology may be retained both by surface
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adsorption on the thread material and by interstitial retention between the
fibres
of the bundle.
The additive 2439 is capable of adsorbing a particular target smoke
constituent
from smoke. The thread is positioned longitudinally along the centre of the
smokeable material 2438, and in this way, the additive 209 is targeted to a
position within the rod of smokeable material 203 corresponding to the central
lateral region of the smoking article. Smoking articles having this
configuration
may therefore be suitable for use when the target smoke constituent has been
found to be present in a higher concentration in a central lateral region of
the
smoking article versus another lateral region.
When the smoking article 201 of Figure 2 is in use, combustion of the rod of
smokeable material 203 generates smoke which is drawn through the smoking
article 201. The smoke constituent may be produced at a higher concentration
in
the central lateral region and due to the targeted positioning of the smoke
constituent reducing additive 209 the concentration of the smoke constituent
may be reduced.
The targeted region may be varied by adjusting the position of the thread 210
within the smokeable material 208. For example, where the smoke constituent
has been found to be present at a higher concentration in a non-central
lateral
position, the thread 210 may be positioned extending longitudinally in a non-
central lateral region of the tobacco rod 203. For example, the rod of
smokeable
material 203 may comprise one or more threads in a peripheral lateral region
of
the rod of smokeable material 203.
In other embodiments, for example where the smoke constituent has been found
to be present at a higher concentration in more than one lateral position, the
thread 210 may be positioned extending longitudinally in more than one lateral
regions of the tobacco rod 203. For example, the rod of smokeable material may
comprise one or more threads extending longitudinally along two, three, or
four
lateral regions of the rod 203. The plurality of threads may comprise
different
additives 209, targeted towards the same or different smoke constituents.
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By means of the arrangement shown in Figure 2, a smoke constituent reducing
additive 209, 210 may be targeted to one or more specific lateral regions
within
the rod of smokeable material 203. Specifically, the position of the thread or
threads 210 within the smokeable material 2438 may be arranged to
substantially coincide with the lateral regions at which a smoke constituent
has
been found to occur at a higher concentration.
The arrangement of a plurality of smoke constituent reducing threads at
several
lateral positions in the requisite quantities, may be used to facilitate
reductions
of smoke constituents at lateral positions where smoke constituents may be
generated at both higher and lower concentrations, hence further lowering
smoke constituent concentrations generated at these positions.
In some embodiments, one or more threads may be used in combination with
other smoke constituent reducing technologies as appropriate. For example, the
wrapper 204 may be a wrapper comprising a smoke constituent reducing
technology as described above in respect of the embodiment of Figure la, lb.
In accordance with embodiments of the type shown in Figure 2a, 2b, the
arrangement of two or more smoke constituent reducing technologies, which
may be the same or different technologies, at two or more lateral positions in
the
smoking article may be used to facilitate reductions of smoke constituents at
lateral positions where smoke constituents may be generated at both higher and
lower concentrations. Specifically, the arrangement of the smoking article
shown
in Figure 2 allows the accurate incorporation of one or more different smoke
constituent reducing technologies into specific location(s) in the smoking
article.
For example, as described above, the one or more threads 210, the content of
the
smokeable material 2438, and the wrapper 204, or any combination of these
parts, may comprise one or more smoke constituent reducing technologies. The
location of the technologies may be easily and accurately controlled, by
adjusting
the materials used and the position and number of threads 210, to target one
or
more smoke constituents based on prior measurements of the concentration of
the smoke constituents present at different locations when the smoking article
is
in use.
.35
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Figure 3a, 3h is a schematic illustration of a smoking article 301 according
to a
further embodiment of the invention. Corresponding reference numerals are
used for features of the smoking article 301 which are the same as those of
the
smoking article 101 described with reference to Figure 1, unless otherwise
stated
below.
As shown in Figure 3a, 3h the smoking article 301 includes a filter 302 and a
rod of smokeable material 303.
In the embodiment shown in Figure 3a, 3h, the smoke constituent reducing
technology is targeted to a lateral region, which is a central region of the
smoking article.
The filter 302 comprises a substantially cylindrical plug of filter material
305
wrapped in a plugwrap 306 around its circumferential surface. The rod of
smokeable material 303 is wrapped in a wrapping material 304. The rod of
smokeable material 303 is connected longitudinally to the filter 302 by
tipping
material 307 overlaying the filter 302 and partially overlaying the wrapping
material 304.
The rod of smokeable material 303 comprises a smokeable material, in this case
tobacco 308. The smokeable material 308 may in general comprise any suitable
smokeable material or blend.
The rod of smokeable material 303 also comprises a smoke constituent reducing
technology 309 which is capable of reducing the concentration of a smoke
constituent in smoke. In the embodiment shown, the smoke constituent reducing
technology comprises particles of a smoke constituent reducing additive 309.
As shown in Figure 3a, 3h, the tobacco rod 303 comprises a plurality of
particles
of additive 309 disposed within the tobacco material 308, concentrated in a
longitudinal region which extends continuously along the whole length of the
rod
303.
The particulate additive material 309 may be applied to the smokeable material
by any suitable method.
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The additive 309 is capable of adsorbing a particular target smoke constituent
from smoke. The additive is positioned longitudinally along the centre of the
smokeable material 308, and in this way, the additive 309 is targeted to a
position within the rod of smokeable material 303 corresponding to the central
lateral region of the smoking article. Smoking articles having this
configuration
may therefore be suitable for use when the target smoke constituent has been
found to be present in a higher concentration in a central lateral region of
the
smoking article versus another lateral region.
Other lateral regions of the rod of smokeable material 303, such as the
peripheral lateral regions, may comprise a reduced amount of additive 309,
such
that the additive 309 is concentrated in the central lateral region.
Alternatively,
the other lateral regions of the rod of smokeable material 303 may comprise no
additive 309.
In other embodiments, for example where the smoke constituent may be found
to be present at a higher concentration in a non-central lateral position,
particles
of additive 309 are disposed within the tobacco material 308 extending
longitudinally in a corresponding non-central position along the tobacco rod
303. For example, the rod of smokeable material may comprise additive in a
peripheral lateral region of the rod of smokeable material 303.
In other embodiments, particles of additive 309 may additionally or
alternatively be located within the smoking article 301 by being incorporated
into the wrapping material 304.. For example, the additive 309 may be adhered
to the inner surface of the wrapping material 304, or adhered to a second
inner
wrapping material positioned within the outer wrapper 304.. The second
wrapper material may be a web material, such as a cellulosic paper web, or
reconstituted tobacco sheet material. The additive 309 may be adhered to the
wrapper 304, or an inner wrapper, as described in WO 2007/104908 and may
be present on both faces of the inner wrapper. Any suitable method may be used
to apply the additive to the wrapper 304.. In other embodiments, the additive
309 may in addition, or alternatively, be incorporated within the structure of
the
wrapper 304 or an inner wrapper, as described in WO 2010/043475.
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The wrapper(s) may comprise a paper wrapper material, or an alternative
material, such as a reconstituted tobacco material. In addition, the
wrapper(s)
may comprise particulate sorbent material as described in WO 2010/043475 and
WO 99/38396.
5
The second sheet may be coextensive with the first wrapper 304, or may only be
provided at one or more discrete portions. The wrapping material 304 may
comprise, in addition or as an alternative to particles of additive, a
different type
of smoke constituent reducing technology, such as a diluent. The diluent may,
10 for example be carried by sorbent material within the wrapper, as
described in
WO 2010/043475.
In other embodiments, for example where the smoke constituent has been found
to be present at a higher concentration in more than one lateral position,
15 particles of additive 309 are disposed within the tobacco material 308
extending longitudinally along more than one lateral region of the tobacco rod
303. For example, the rod of smokeable material may comprise two, three, or
four longitudinally extending lateral regions of particulate material.
20 In some embodiments, the additive 309 may comprise, instead or in
addition to
particulate material, portions of the carbon fibre thread material described
above in respect of the embodiment shown in Figure 2a, 2b.
The additive 309 may be inserted into the smokeable material 308 during
25 formation of the rod of smokeable material 303.
When the smoking article 301 of Figure 3 is in use, combustion of the rod of
smokeable material 303 generates smoke which is drawn through the smoking
article 301. The smoke constituent may be produced at a higher concentration
in
30 the central lateral region and due to the targeted positioning of the
smoke
constituent reducing additive 309 the concentration of the smoke constituent
may be reduced.
In some embodiments, the particulate material 309 present in the rod of
35 smokeable material are particles of a porous carbon material and the
smoke
constituent reducing additive is carried within the pores of the porous
material.
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In some embodiments, heat from the combustion of the smokeable material
causes the release of the additive from the porous particulate material. The
porous material may also function as a smoke constituent reducing additive.
Alternatively, or in addition, the particulate material 309 may be impregnated
with one or metals such as silver or copper, which may be capable of acting as
a
catalyst to remove or reduce smoke constituents.
By means of the arrangement shown in Figures 3a, 3h, a smoke constituent
reducing additive 309 may be targeted to specific lateral regions within the
rod
of smokeable material 303. Specifically, the additive 309 may be incorporated
into the rod of smokeable material at one or more lateral regions which
substantially coincide with the lateral regions at which a target smoke
constituent has been found to occur at a higher concentration.
The arrangement of one or a plurality of smoke constituent reducing additives
in
the smoking article may be controlled to reduce the concentration of the smoke
constituent present at the one or more first lateral regions at which the
constituent has been found to occur at a higher concentration. Optionally one
or
a plurality of smoke constituent reducing additives may also be included to
target one or more second lateral regions in which the smoke constituent has
been found to occur at a lower concentration.
In accordance with embodiments of the type shown in Figure 3a, 3h, the
arrangement of two or more smoke constituent reducing technologies, which
may be the same or different technologies, at two or more lateral positions in
the
smoking article may be used to facilitate reductions of smoke constituents at
lateral positions where smoke constituents may be generated at both higher and
lower concentrations. Specifically, the arrangement of the smoking article
shown
in Figure 3 allows the accurate incorporation of one or more different smoke
constituent reducing technologies into specific location(s) in the smoking
article.
For example, as described above, the one or more additives 309, the content of
the smokeable material 308, and the wrapper 304., or any combination of these
parts, may comprise one or more smoke constituent reducing technologies. The
location of the technologies may be easily and accurately controlled, by
adjusting
the materials used and the position and quantity of additive 309, to target
one
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or more smoke constituents based on prior measurements of the concentration
of the smoke constituents present at different locations when the smoking
article
is in use.
In some embodiments, the smoking article may comprise a combination of
different smoke constituent reducing technologies. Different smoke constituent
reducing technologies may be used in combination as appropriate. For example,
the wrapper 304 may be a wrapper comprising a smoke constituent reducing
technology as described above in respect of the embodiment of Figure la, lb.
In
another example, a smoking article may comprise additive 309 in combination
with one or more threads as described above in respect of the embodiment of
Figure 2 a, 2b. Alternatively, the co-axial arrangement of Figure la, lb may
be
used in combination with the particulate additive of Figure 3a, 3h, and/or
with
one or more threads as described above in respect of the embodiment of Figure
2a, 2b.
Without wishing to be bound by any theory, the effects of the smoke
constituent
reducing technologies when longitudinally positioned at different lateral
regions
in the smoking article may arise from a change in combustion and/or pyrolysis
profile of the smoke components in the aerosols generated during the smoking
process. This may be the result of the physical presence of these technologies
in
specific lateral locations within the smoking article, which may exert
physicochemical effects on thermal processes within the combustion and/or
pyrolysis zones, resulting in reductions of several smoke constituents. For
example, the smoke constituent reducing technology may inherently minimise or
eliminate the generation of target smoke constituents, and means of targeting
the smoke constituent may include catalysis, absorption or other physical
means,
chemical reaction, and exothermic or endothermic means.
In smoking articles in which the smoke reducing technology is positioned
distal
from the coal, such as in the filter, the smoke constituent reducing
technology
may inherently minimise or eliminate the generation of target smoke
constituents. Means of targeting the smoke constituent may include catalysis,
absorption or other physical means, and by means of chemical reaction.
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As discussed in the specific Examples, co-axial cigarette constructions where
longitudinal smoke constituent reducing technologies are located at different
lateral positions demonstrate reductions in the level of specific targeted
smoke
constituents in comparison to control smoking articles.
The methods and systems of the present disclosure, as described above and
shown in the accompanying Figures, provide for improved smoking articles and
techniques for making the same. It will be apparent to those skilled in the
art
that various modifications and variations can be made to the smoking article
and
method of the disclosed embodiments without departing from the spirit and
scope of the disclosed embodiments. Thus, it is intended that the present
disclosure includes modifications and variations that are within the scope of
the
subject disclosure and equivalents. 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 equivalents to the claims, and that other embodiments may be
utilised and modifications may be made without departing from the scope
and/or spirit 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 following examples are provided to illustrate the present invention and
should not be construed as limiting thereof.
Examples
Experimental System and Procedure
A suitable experimental system for obtaining samples of gases from the burning
portion of a smoking article at various times and at various locations within
the
smoking article, before, during and after a puff, is described below.
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Untipped tobacco rods were prepared, 70 mm long and 8 mm in diameter. The
cigarette paper had a permeability of i8o cm3 mini (io cm2)-1 (io cm water )-
1,
and the tobacco was cut at 56 cuts per inch. The cigarettes were selected for
weight (0.99 0.02 g) and pressure drop (9.3 0.5 cm water at an air flow of
17.5 cm3 S-1), and were conditioned at 21 c and 6o% relative humidity.
The cigarettes were smoked in an atmosphere of 21% v/v oxygen/79% v/v argon
inside a cubic Perspex chamber of 140 mm side. The gas mixture was passed
vertically through the chamber at a flow rate of 250 cm3 s-1, equivalent to a
linear
velocity of 12.8 mm s-i or o.18 miles per hour past the cigarette. This is
equivalent to a Beaufort force o air condition ("calm air"). Under these
conditions, the burn rates of the cigarette during the third puff, and in the
preceding smoulder period were the same as when the cigarette was smoked in
open air (1.29 and a mean 0.069 mm s-1 respectively). Furthermore, no decrease
in the bulk concentration of oxygen in the smoking chamber could be detected
as
the cigarette smouldered, or when puffs were taken. The puff by puff carbon
monoxide deliveries were effectively the same in the smoking chamber as when
smoked in open air.
The smoke was withdrawn from the cigarette using a quartz probe/thermocouple
mounted radially into the cigarette, filtered using a mini-Cambridge filter
unit,
and analysed using a quadrupole mass spectrometer.
The gas concentrations during the third puff in the smoking regime was
determined, together with those during the smoulder period before and after
that puff. The cigarette was smoked singly in the smoking chamber using a
Cigarette Components Ltd. C.S.M.io smoking machine, taking a 35 cm3 puff of 2
seconds duration, once per minute under restricted smoulder conditions. The
pressure-time profile of the puff was square.
For a given position of the probe in the cigarette, at least four replicate
experiments were performed. The mass spectrometer was systematically
calibrated before each replicate experiment, using known gas mixtures. In
successive experiments, the probe was inserted into the cigarette for
distances of
o, 1, 2, 3 and 3.5 mm from the central axis, and at distances of between -10
and
+10 from the line of paper burn at the start of the puff (Table 1).
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Table
INITIAL POSITIONS OF PROBE FOR THE INTERNAL CONTOUR DETERMINATIONS*
Distance From
Central Axis
Initial** Axial Distance (mm) from Paper Burn Line
of Cigarette
(TD.111)
o -10 -6 -4 -2 0 2 4 6 8 10
1 -10 -6 -4 -2 0 2 4 & 8
2 -10 -6 -4 -2 0 2 4 6 8
3 -10 -6 -4 -2 0 2 4 6
3.5 -10 -6 -4 -2 0 2 4
* Axial positions in the unburnt tobacco rod are given as negative
distances from the line of paper burn, the burn line is given the
axial position of zero, and positions in the coal and ash are given
as positive distances from the burn line.
** The distance at the start of the third puff in the smoking regime.
During the puff, the paper burn line moves down the tobacco rod with
a linear speed of 1.29 mm s-1. For about 15 s after the end of the
puff, the paper burn line is stationary; it them moves with a linear
speed of 0.069 mm s-1.
Results of smoke constituent concentration determination
Example gas concentration profiles obtained before, during and following a 2-
5 second puff for one position of the probe during the cigarette, are shown
in
Figure 4. The profiles shown in Figure 4 illustrates the gas concentration as
a
function of time, from the start of the puff, or axial distance from the burn
line,
for a given initial position of the probe in the cigarette. The 95% confidence
limits of each mean point (mean of four replicates) are also shown. These
10 depend on the quantity of gas and the position in the smoking cycle.
Example contour distributions of temperature, oxygen, carbon monoxide, carbon
dioxide, hydrogen and propane inside the combustion coal of the cigarette, at
various stages during and following the third puff are given in Figures 5-10.
In Figures 5-10, the x-axis is the distance from the line of paper burn (mm)
and
the y-axis is the diameter of the cigarette (which was 8mm).
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The gas concentration contour distributions shown in Figures 5-10
are obtained from a combination of many profiles for different initial probe
positions, and show the gas concentration distribution throughout the coal at
a
given time point in the smoking cycle.
Alternate contours in each plot are marked with the value of the contour, and
the
serrated contours represent valleys. The sign convention of the axial
distances
used in these diagrams is defined in the first footnote to Table 1. The
temperature distributions were obtained using a thermocouple positioned at the
end of the gas sampling probe.
The concentration of the measured analytes (smoke constituents) can be seen to
vary considerably across the width of the smoking article. For example, during
puffing, oxygen levels drop from about 20 %V/V to near zero near the axial
middle of the coal area, whereas carbon monoxide levels generally are at their
highest at this position. Carbon dioxide also tends to be high in the axial
middle
coal area.
Most of the incoming oxygen during the puff appears to be consumed before it
can reach the centre of the coal.
Propane concentration seems to be highest in almost symmetrically off set
positions axially relative to the coal (Figures 5-9).
Figure lo illustrates the concentration profiles of the analytes 6 seconds
from the
start of a 2 second puff, (i.e. 4 seconds into the inter-puff smouldering
period).
Again, oxygen levels approach zero axially in the middle coal area, with
carbon
monoxide and carbon dioxide tending to be at highest levels in a central
lateral
region. Propane concentration appears to be highest in symmetrically off set
positions axially relative to the coal.
Smoke constituent reducing technologies
Following the observation that carbon monoxide levels are highest near the
axial
centre of the coal, it was hypothesised that smoke component reducing
technologies directed towards carbon monoxide would be effective when
longitudinally positioned in a central lateral region of a cigarette.
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Co-axial design cigarettes similar to those shown in Figure I were produced in
which smoke constituent reducing technologies directed towards carbon
monoxide were longitudinally positioned in central lateral regions of a
cigarette.
For the purpose of this work, the term 'Smoke Constituent Reducing Technology'
is abbreviated to `SCRT'.
Two different smoke constituent reducing technologies were investigated
utilising a co-axial cigarette construction. The smoke constituent reducing
technologies are described in Table 2.
Table 2: Smoke Constituent Reducing Technologies
Smoke Constituent Type of
Description
Reducing Technology Technology
A cigarette paper wrapper incorporating iron oxide,
SCRT-A Catalyst
with potential to reduce carbon monoxide levels
A non-tobacco based reconstituted material
incorporating smoke dilution technology which is
SCRT-B Diluent designed to dilute tobacco smoke with a
smoke
diluent, and hence dilute smoke constituents: this
was incorporated into a tobacco blend
These technologies were included longitudinally within a co-axial cigarette
design, in central lateral positions. The effect on smoke chemistry was
assessed
by comparison with control co-axial cigarettes manufactured from control
materials.
Co-axial cigarettes similar to those described above and shown in Figure I
were
prepared. The cigarettes were constructed using either of two different types
of
cigarette paper as the inner wrapper (111), and either of two different types
of
smokeable material as the first (inner) smokeable material (114) in the inner
rod
(110).
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The inner rod was a super-slim cigarette construction, having a diameter of
about 17mm. The outer diameter of the cigarettes was about 24-25mm. The co-
axial cigarettes were manufactured utilising two cigarette making machines in
series, the super-slim tobacco rod from the first machine being fed into the
second to enshroud this with an outer annulus of smokeable material and apply
the outer overwrap.
The filters (102) of the cigarettes were non-ventilated.
According to Figure 1, the outer annulus of smokeable material corresponds to
a
second smokeable material (115) in the outer rod (112), which circumscribes
the
inner rod (no).
The co-axial cigarette design requires both an inner and an outer wrapper (see
Figure 1, 111, 104). The outer wrapper used was the same for all of the
cigarette
samples studied, and consisted of 50 CU permeability paper with a basis weight
of 23gsm. This paper is referred to as Cigarette Paper 2.
The inner rod wrapper (111) used was variable in different cigarette samples
studied. The first type of wrapper, which was the control wrapper and referred
to
as Cigarette Paper 1, was a 25 CU permeability paper with a basis weight of
23gsm. This wrapper did not comprise a smoke constituent reducing technology.
The second type of wrapper, referred to as "Iron Oxide Paper", was a 45 CU
permeability iron oxide type paper where the iron oxide is used as a filler,
manufactured by a commercial cigarette paper manufacturer. The paper had a
basis weight of 26g5m, with an iron oxide content equivalent to 16.2% w/w
iron.
The first type of smokeable material, referred to as 'Blend i', comprises a
blend
of defined tobacco materials in known proportions. This blend did not comprise
a smoke constituent reducing technology.
The second type of smokable material, referred to as 'Diluent Blend',
comprises a
mixture of Blend 1 and a sheet material containing a chalk based band-cast
sheet
with the addition of substances to act as a smoke diluent (`Diluent Sheet').
The
Diluent Sheet was blended at 5o% inclusion by weight with 'Blend i'. The
Diluent
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Blend incorporating the Diluent Sheet is designed to dilute the tobacco smoke
(and hence smoke constituents) with a smoke diluent ¨ in this case the Diluent
Sheet contained triacetin and glycerol to act as smoke diluents. The
composition
of the Diluent Sheet is presented in Table 3.
Table 3: Composition of the Diluent Sheet of the Diluent Blend
Ingredient % (by weight)
Chalk 71-
Alginate 7.5
Caramel 1.5
Glycerol 3
Triacetin 17
Co-axial cigarettes were constructed to study the effect of incorporating the
smoke constituent reducing technologies longitudinally in central lateral
positions within the co-axial construction. The following cigarette designs
were
manufactured, which facilitated a study of the technologies, individually and
in
combination, on smoke chemistry when compared to co-axial cigarettes made
from control materials (control cigarettes). The co-axial cigarette design
experimental matrix is given in Table 4.
Table 4: Co-axial Cigarette Design Experimental Matrix
Lateral Position Lateral Position
Cigarette
Comment
Sample
Outer Outer
Inner Blend Inner Wrapper
Blend Wrapper
Cigarette
1 Blend 1 Blend 1 Cigarette Paper 1
Paper 2 Control Cigarette
(Control)
Cigarette
Blend 1 Blend 1 Iron Oxide Paper
2 Paper 2 SCRT-A
(SCRT-A)
DiluentCigarette
Blend 1 Cigarette Paper 1
3 Blend Paper 2 SCRT-B
(SCRT-B)
DiluentCigarette
Blend 1 Iron Oxide Paper
4 Blend Paper 2 SCRT-A and SCRT-B
(SCRT-A)
(SCRT-B)
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By comparing Cigarette 2 to Control 1, the effect of SCRT-A (Iron Oxide Paper)
may be ascertained.
5 By comparing Cigarette 3 to Control 1, the effect of SCRT-B (Diluent
Blend) may
be ascertained.
By comparing Cigarette 4 to Control 1, the combined effect of SCRT-A (Iron
Oxide Paper) and SCRT-B (Diluent Blend) may be ascertained.
A cellulose acetate filter was used on all cigarettes. The filter was not
ventilated.
The cigarettes were manufactured to a firmness of about 72% and not exceeding
a pressure drop of i6ommWG.
The cigarettes were smoked under ISO smoking regime, which is set out in Table
5.
Table 5: Smoking Regime
Puff Volume (mL) Puff Duration (s) Puff Frequency (s)
35 2 6o
The amounts of carbon monoxide and NFDPM present in the mainstream smoke
produced by the cigarettes were determined. The term 'NFDPM' is a term of art,
determined utilising a test methodology as would be understood by a skilled
person. It is defined as the weight of mainstream smoke particulate matter
trapped on a high efficiency particulate filter, minus the weight of nicotine
and
water on the filter. It is usually expressed in weight units of milligrams per
cigarette.
The carbon monoxide content of the smoke was calculated as the ratio of the
amount of carbon monoxide to the amount of NFDPM, and is shown in Table 6.
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Table 6: Carbon Monoxide : NFDPM Ratio of Non-Tip Ventilated Cigarettes
Cigarette CO : NFDPM % change compared to Control 1
Sample Ratio
1 I-43 Control 1
2 1.25 -12.59
3 1.08 -24.48
4 1.09 -23.78
It can be seen from Table 6 that for Cigarette Sample 2 incorporating SCRT-A
(Iron Oxide Paper) compared to Control 1, the level of carbon monoxide is
reduced relative to the level of NFDPM.
Likewise, for Cigarette Sample 3 incorporating SCRT-B (Diluent Blend)
compared to Control 1, there is a reduction in the level of carbon monoxide
relative to the level of NFDPM.
Finally, the reduction in the level of carbon monoxide relative to that of
NFDPM
is also demonstrated for Cigarette Sample 4, which incorporates SCRT-A and
SCRT-B, compared to Control 1.
Thus, the targeted incorporation of a smoke constituent reducing technology
into
a smoking article, based on the prior determination of the location of the
greatest concentration of the smoke constituent, results in cigarette
constructions having an increased capacity to reduce target smoke constituents
relative to NFDPM.
In conclusion, the concentration of carbon monoxide, as an exemplary smoke
constituent, produced in a smoking article as it is in use was determined at
various lateral positions and at various time points during puffing and
between
puffs. Carbon monoxide was found to be produced at the highest concentrations
in the central lateral region of the smoking article. Smoking articles were
therefore produced comprising one or a combination of two different smoke
constituent reducing technologies positioned in substantially central lateral
regions of the smoking articles to target carbon monoxide. The effect of the
smoke constituent reducing technologies on the concentration of carbon
monoxide was investigated. The first smoke constituent reducing technology was
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a wrapper comprising iron oxide, positioned in an intermediate annular region
of the smokeable material, and the second smoke constituent reducing
technology was the use of a diluent blend in the tobacco blend in a central
lateral
region of the smokeable material. The results obtained clearly show that the
targeted positioning of smoke constituent reducing technologies within a
smoking article reduced the concentration of carbon monoxide produced. This
method provides a useful new tool to the smoking article designer.
