Note: Descriptions are shown in the official language in which they were submitted.
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TOBACCO-CONTAINING CONSUMABLE FOR AEROSOL GENERATING
DEVICES
Many alternatives to traditional combustible tobacco products have been
launched in recent years.
Electronic Cigarettes use battery power to heat a nicotine-containing aerosol-
generating liquid to form an inhalable nicotine-containing aerosol. Such
products
tend not to contain tobacco.
Heated Tobacco Products use various energy sources and means to heat a
tobacco-containing consumable to generate an inhalable aerosol that contains
some components derived from tobacco, including flavour and nicotine.
There are also various "hybrid" products which can combine technology from
both electronic cigarettes and Heated Tobacco Products in order to generate an
inhalable nicotine-containing aerosol wherein flavour and nicotine can
originate
from either the aerosol-generating liquid or the tobacco portions.
Specific examples of existing technologies include:
W09639880 and W02013190036 describe a cigarette-like cylindrical
consumable article, with a distal end containing tobacco-derived material,
typically crimped reconstituted tobacco sheet, a mouth-end filter typically
containing multiple segments, and an overwrap made from paper. Said article is
intended to be electrically heated in order to produce an inhalable nicotine-
containing aerosol.
W02016207407 also describes a tobacco consumable intended for consumption
by heating, namely a distal tobacco-derived portion, a mouth-end filter and a
paper overwrap.
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US2009151717 describes a small metallic capsule ("pod") with a foil lid that
is
pierced prior to use. Inside the pod, the tobacco-derived material typically
comprises finely ground tobacco particles, humectants and flavourings.
W02016159013 describes a device in which an aerosol is generated by heating
a liquid which is then passed through a separate tobacco portion; the tobacco
portion imparts flavour and/or nicotine to the final aerosol. The tobacco
portion
can be held within a moulded plastic capsule with a mesh at the distal end and
a
small filter at the mouth-end.
W02016135342 describes a product which operates in a similar manner to that
described in W02016159013, however the tobacco portion and the liquid
heating unit are comprised as one unit. The tobacco portion is held within a
moulded plastic structure with a filter at the mouth-end.
With regards to the consumable units for these products, there are some
recognised limitations.
For example, with consumables manufactured using cigarette-rod-making
technology the user can mistakenly ignite the consumable and potentially
inhale
unintended and or undesirable combustion products. Also, consumables utilising
plastic or metal capsules require bespoke manufacturing machinery, have
limited environmental recyclability, and have high material & manufacturing
costs.
The current invention describes a tobacco-containing consumable article for
use
in aerosol-generating devices comprising at least a tobacco-derived portion, a
distal filter portion and a mouth-end filter portion held together in a
continuous
overwrap, with a compressibility factor less than 10%.
The article may have a total pressure drop <120mm water column along its
longitudinal axis. The pressure drop is preferably in the range of 5 to 40 mm
water column and more preferably is in the range 10 to 30 mm water column.
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Such a consumable may be manufactured using conventional cavity-filter-
making technology, well known within the tobacco industry and shown in
U56537186 for example. In such prior art arrangements, a filter is
manufactured
with a distal filter portion, a cavity to receive typically a solid granular
material
such as activated carbon, and a mouth-end filter portion all held together by
a
paper overwrap. Products have also existed which utilised tobacco-derived
material within said cavity to impart or attenuate flavour to the smoke as it
passes through the filter.
The current invention therefore allows production of consumables via readily-
available high- speed production machinery, using proven manufacturing
technology, with low material and production costs, material & design
flexibility,
and can be compatible with a variety of aerosol-generating systems.
In some examples, the article may modify one or more other organoleptic
properties of the aerosol (e.g. modifying the feel or smell or look of the
aerosol to
the user).
In some examples, the article may comprise a substance that modifies the PH of
the aerosol by either lowering or raising the PH (e.g. modifying the acidity
or the
basicity of the aerosol).
In some examples, the article may modify (e.g. reduce) the amount of aldehydes
in the aerosol.
As described herein, a non-combustible tobacco article means an article
containing a tobacco-derived portion that is not intended to be combusted as a
whole or in part during use, and no part of said article is intended to be lit
during
use. Furthermore the construction of said article resists ignition through the
use
of filter materials such as cellulose acetate at both the distal and mouth
ends.
The term aerosol shall be interpreted to include gas, vapour, droplets,
condensates, particulates and combinations thereof. An inhalable aerosol shall
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mean an aerosol with an average particle size as measured by laser dispersion
ranging from 0.1 to 10 pm, more preferably 0.1 to 1.5 pm.
Examples of the present invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 is a side schematic view of an article according to the invention;
Figure 2 is a side schematic view of an article according to the invention
showing
the longitudinal axis;
Figure 3 is a side perspective view of an example filter portion and overwrap
for
use in the invention employing multiple layers in its overwrap,
Figures 4, 5 and 6 are side schematic views of example articles according to
the
invention with different overwrap configurations;
Figures 7 and 8 are schematic views of a device employed in combination with
the article of the invention;
Figure 9 shows an example filter portion that can be employed in the article
of
the invention; and
Figure 10 is a schematic view of an alternative method of employing the
article
of the invention to generate vapour.
Figure 1 depicts the basic construction of the article of the invention. The
mouth
end 3 is the end of the article intended as the exit of the aerosol towards
the
user. The distal end 1 is the opposite end of the article, typically intended
as the
inlet for air and other materials into the article. A tobacco portion sits
there
between. By way of example, the length of the tobacco portion 2 is in the
range
7mm to 17mm and preferably in the range lOmm to 13mm, the length of each of
the filter portions 1,3 is in the range 3mm to 15mm and preferably in the
range
4mm to 6mm and the diameter of the flavour container is in the range 5mm to
8.5mm. The dimensions depend upon a combination of the need to provide
sufficient material within the tobacco portion 2 to provide a desired flavour
effect
whilst ensuring a balance between the three sections overall to provide an
appropriate pressure drop whilst retaining overall product strength and
compressibility.
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In the example of Figure 1 part 2 is a tobacco-derived portion, which can
include
single-grade tobacco, blended tobacco grades, leaf, stem, dust, reconstituted
tobacco, washed tobacco, extracted tobacco, treated tobacco, tobacco extracts
and mixtures thereof. The tobacco-derived portion 2 can be produced from
5 tobacco plants by methods including harvesting, drying, cutting,
shredding,
grinding, extraction, reconstitution, extrusion and combinations thereof. The
tobacco-derived portion 2 can be present in the physical form of leaf, stem,
dust,
reconstituted sheet, crimped, folded, shaped, beaded, granulated and mixtures
thereof. In most examples the tobacco portion 2 comprises tobacco although
other botanicals or flavour agents may also be used. In variations of the
examples shown, the tobacco portion 2 may be occupied by a cut tobacco rod or
fully or partially by ground tobacco. Selection of the material for the
tobacco
portion 2 is dependent upon a number of factors such as desired level of
flavour
delivery and the requirements to meet an appropriate pressure drop.
In a preferred embodiment of this invention, the tobacco derived portion 2 is
obtained by carefully selecting a mix of cured tobacco grades based upon
desirable taste attributes and low levels of undesirable chemicals; reducing
the
particle size of the plant material by cutting or grinding to a size suitable
for
further processing; treating the tobacco material to further reduce
undesirable
components via a suitable combination of processes including liquid
extraction,
heat treatment, pressure treatment and chemical treatment; adding ingredients
including humectants to produce aerosol and flavourants, reconstituting the
tobacco into a sheet format; drying to produce a stable material which is
added
to the tobacco article either intact as crimped sheet or as fragments of cut
or
shredded sheet. The above steps can be interchanged, although size reduction
is best formed at an early stage in the process and extraction is preferable
before addition of flavours to minimise losses of the added flavours. Drying
is
normally the final stage, although flavour/humectants can be added at the end.
In some examples a tobacco cut rag is used in the tobacco portion 2 in which
case the density of the tobacco cut rag may be in the range of 150- 500 mg per
cm3, preferably in the range 180- 280 mg per cm3, and most preferably in the
range 200-250 mg per cm3. Control of this size ensures provision of the
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maximum possible tobacco quantity within the volume of the tobacco portion 2
so that there is maximum transfer into the aerosol.
In a some examples, the tobacco portion 2 comprises a flavour material that
has
been ground or otherwise treated or formed so that it is in the form of
particles,
for example, powder, granules, grains, fibres, beads, pellets or the like so
as, for
example, to increase the active surface area or amount of the flavour material
in
order to maximise the amount of flavour imparted to a vapour and/or aerosol
stream flowing through the article.
As used herein, the terms "flavour" and "flavourant" may refer to materials
which, where local regulations permit, may be used to create a desired taste
or
aroma in a product for adult consumers. They may include extracts (e.g.,
licorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek,
clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry,
berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint,
peppermint, lavender, cardamom, celery, cascarilla, nutmeg, sandalwood,
bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil,
cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger,
anise, coriander, coffee, or a mint oil from any species of the genus Mentha),
flavour enhancers, bitterness receptor site blockers, sensorial receptor site
activators or stimulators, sugars and/or sugar substitutes (e.g., sucralose,
acesulfame potassium, aspartame, saccharine, cyclamates,
lactose,
sucrose, glucose, fructose, sorbitol, or mannitol), and other additives such
as charcoal, chlorophyll, minerals, botanicals, or breath freshening agents.
They may be imitation, synthetic or natural ingredients or blends thereof.
They
may be in any suitable form, for example, oil, liquid, solid, or powder. For
example, a liquid, oil, or other such fluid flavourant may be impregnated in a
porous solid material so as to impart flavour and/or other properties to that
porous solid material. As such, the liquid or oil is a constituent of the
material in
which it is impregnated.
To prevent excessive pressure drop it is preferable to have the major axis of
the
tobacco derived sheet running parallel to the longitudinal axis 6 of the
article of
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the invention to form pathways for air to pass (see figure 2, part 2). In an
alternate preferred embodiment of this invention, the tobacco derived material
is
prepared as above except that the tobacco derived material is reconstituted
into
a granular or particulate format which can then be added to the invention.
Preferably the granular or particulate tobacco derived material is produced by
extrusion, because this ensures consistency of particle size and shape as well
as ensuring uniform distribution of any added flavourant or humectant.
In the specific case of the material of the tobacco portion 2 comprising a
continuous fibre ground tobacco the tobacco weight is preferably in the range
of
2 mg to 6 mg per mm of the tobacco portion.
In the specific case of the material of the tobacco portion 2 comprising short
cut
fibres ground tobacco the tobacco weight is preferably in the range of 6 mg to
15
mg per mm of the tobacco portion 2.
Figure 2 shows the longitudinal axis 6 of the article of the invention, taken
as the
major axis of the article and running from the mouth end 3 to the distal end
1.
Other axes are taken as perpendicular to this longitudinal axis. Definition of
such axes is important in the measurement of key physical parameters that
control the integrity of the product during storage & use, and of the sensory
experience that the user receives.
"Pressure drop" or "draw resistance" is measured using the Coresta
Recommended Method 41.
(https://www.coresta.org/sites/default/files/technical_documents/main/CRM_41-
update2_0.pdf) and expressed as millimetres water-column equivalent. This
design feature determines how the user can extract a volume of aerosol from
the
consumable/device with reasonable effort.
"Compressibility" is measured in the longitudinal axis 6 by application of a
fixed
force of 10 Newtons at points 5 (see figure 2), and measuring the deflection
distance as a percentage of the total product length. Such measurement can be
performed using equipment such as lnstron's electromechanical rig 3300.
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In Figure 1 part 4 shows an "overwrap": one or more sheets of material that
provide the outer surface of the article, act to hold the separate elements
(distal
end filter 1, tobacco derived portion 2 and mouth-end filter 3) in sequence
relative to each other and provides structural strength to the article
sufficient for
required manipulation by the user, in particular during insertion and removal
from
an associated device. An overwrap 4 typically comprises paper, plastic, foil,
laminates or combinations thereof. An overwrap 4 can comprise a single layer
over the entirety of the article or can have multiple layers at different
points as
shown in Figure 3, parts 8 and 9, as may be required depending on the
underlying construction of the article, for example multi-segment filter
portions
are typically held together with an outer wrapper to assist manufacturing
processes. Overwraps of particular relevance to this invention preferably have
grammage in the range of 20-100 grams per square meter (gsm). A preferred
embodiment utilises a rigid non-porous overwrap in the range of 40 ¨ 200 g/m2
composed of transparent cellulose-based paper without chalk overprinted with
metallic inks. The lower limit of the grammage is usually determined by the
need
for opacity and physical strength for the end consumable. The upper limit of
the
grammage range is set by the operability of the machinery, which can perform
if
the overwrap material is too thick. In terms of the preferred embodiment, an
employment of a rigid non-porous overwrap without chalk, this had advantages
in that printing can be performed on specific areas to provide shaped windows,
logos etc.
In some examples, the overwrap 4 is configured so that its acts as a liquid
resistant barrier that prevents liquid, for example, condensation that forms
around the article when it is in use, from getting into the interior of the
article and
making the tobacco portion 2 soggy. In one example, a liquid resistance
wrapper layer is used in the overwrap 4 comprises paper impregnated with a
barrier material or Natureflex or other suitable thin polymer film.
In a preferred embodiment of the present invention, the overwrap 4 is supplied
as a continuous roll of material which is bent in the cross-direction, shaped
into a
continuous cylinder and affixed to itself using glue. Concurrent with the
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formation of this continuous cylinder of overwrap the internal elements,
namely
filter portions 1,3 and tobacco derived portions 2, are supplied and affixed
to the
overwrap 4 as appropriate. This continuous cylinder is then cut into the
discreet
tobacco articles. This process can be carried out in a continuous manner using
a machine for producing cavity filters as known in the art. In an alternative
preferred embodiment, the continuous roll of overwrap is formed into a helix
and
affixed to itself to form the continuous cylindrical shape with a resultant
spiral
seam (as seen in Figure 4). A helical arrangement has the further advantage
that the seam can provide further structural rigidity to the complete article
by
preventing compression in the cross-direction.
Figures 4, 5 and 6 show exemplary embodiments wherein regions 11 are
transparent, and regions 12 are opaque. Transparent overwrap is defined by the
ability to allow the user to visually perceive the contents inside the
article.
Suitable properties can be found with transparent, semi-opaque and translucent
materials. Accordingly regions of transparency can be created within an
overwrap 4 by altering the composition of the overwrap 4 in that region by
means including reducing the amount of print, reducing the amount of an opaque
layer, removal of a foil layer or combinations thereof. A preferred embodiment
utilises a transparent cellulose- based paper opacified with metallic inks to
give a
foil-like appearance overall, and has regions with no metallic ink that serve
as
transparent windows 11 to view the contents inside the article. Most
preferably
these transparent windows 11 are aligned with the tobacco derived portion 2.
During storage and use the physical properties of the overwrap 4 can be
affected by absorption of volatile, liquid and aerosol components. For
example,
paper based overwraps can absorb moisture and other liquids which soften the
overwrap reducing its structural integrity; this can be undesirable as it can
affect
the user's ability to remove the article from the associated device. It can
also
have a detrimental effect upon the visual aesthetics of the overwrap, for
example
causing staining. Hence it is desirable to provide overwraps that resist the
absorption and therefore retain desirable structural properties and
appearance.
To resist absorption overwraps can be composed of plastics and foils; have a
plastic or foil inner layer; have an inner surface coated with varnish or
lacquer;
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be composed of paper with low propensity to absorb liquids and combinations
thereof. These may include trilaminate foils with a PE:Al:PET type
construction.
In a preferred embodiment, the overwrap is transparent cellulose-based paper
without chalk which exhibits a low absorption propensity. An alternate
preferred
5 embodiment the overwrap 4 is a transparent film of plastic. An alternate
preferred embodiment the overwrap 4 is a paper based material coated with a
layer of alkyl ketene dimer (AKD) on the inner surface.
Filter portions (Figure 1, parts 1 and 3) act as a physical barrier to contain
the
10 tobacco-derived portion 2 and maintain the overall structural integrity
of the
tobacco article predominantly in the minor axis whilst allowing the desired
air
and aerosol to pass through. In some examples, the material of the filteris
moisture resistant so that the filter portions 1,3 maintain their shape in
use. The
mouth-end filter portion 3 can in addition act to prevent undesirable fine
dust
particles from the tobacco derived portion 2 reaching the user and removes
aerosol particles larger than those of an inhalable aerosol.
The filter portions 1, 3 can each be provided by a filter portion 21. To
enhance
airflow through the invention, the pressure drop of the filter portions 21
(shown in
Figure 9), can be reduced by the introduction of one or more airflow channels
22
in the longitudinal axis. Airflow channels 22 can pass the entire length of
the filter
portion. Preferably airflow channels 22 pass through up to 95% of the filter
portion length, leaving at least 5% of the filter portion intact to retain
tobacco
particles. Airflow channels 22 can be introduced once the filter portion 21 is
formed by using lasers to burn through the filter material or by use of a
mechanical pin to punch the channel 22. Preferably airflow channels 22 are
formed by introducing a mandrel or pin into the filter material during the
formation process to shape the channel.
In some examples, the pressure difference across either of the portions 1,3 is
in
the range 0.1mm to 2mm water column per mm length of the section.
Filter portions 21 typically are composed of cellulose acetate, paper,
plastics,
polymers such as polyethylene, polypropylene or polylactic acid and
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combinations thereof. In a preferred embodiment of the present invention the
filter portion 21 is composed of cellulose acetate fibres plasticised with up
to
15% triacetin. Filter portions 21 may be homogenous or composed of multiple
contiguous segments. Filter portions 21, and more preferably the mouth-end
filter portion 3, can contain attenuants, flavourants and aesthetic elements.
A different additional flavour component may be placed in each of the end
filter
portions 1,3 (e.g. a flavour capsule in distal portion 1 and a flavoured
thread or
line in the mouth portion 1).
In some examples, the filter portions 1,3 comprise a fibrous material and may
be, for example, a fibrous material that is typically used as a filter
material in
traditional cigarette, examples including cellulose acetate fibres,
polypropylene
fibres, polyster fibres and paper, including crimped paper. Other materials
may
be used for example, nylon and the like.
In another example, the material of the tobacco portion 2 and the material in
the
two filter portions 1,3 comprises a multiplicity of short cut CA fibres (for
example
fibres cut using a so called Turmalin apparatus) randomly orientated. Short
cut
CA fibres with for example ground tobacco in tobacco portion 2, may use just
enough of the fibres to hold the ground tobacco in a rod form. Benefits of
this
arrangement allow for a lower pressure drop of vapour and/or aerosol flow and
additionally there is reduced or no need for a plasticiser, for example,
triacetine
to hold the rod form as is required for a continuous fibre CA. Furthermore,
use
of short cut CA fibres enables the use of less CA and more tobacco than in the
case of using a long continuous CA fibre.
In some examples, the percentage weight of first flavour component (and any
other components e.g. charcoal, plasticiser) in the filter portions 1,3 to the
weight
of the material of the tobacco portion 2 is in the range 10% to 90% and
preferably in the range 70% to 90%.
In the specific case of the article comprising a continuous fibre and the
tobacco
portion 2 comprising ground tobacco the tobacco weight to the fibre weight is
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preferably in the range of 40% to 60% and most preferably in the range of 45%
to 55%. The fibre weight is preferably in the range of 75% to 95% and most
preferably in the range of 80% to 90%.
Attenuants remove undesirable chemicals from the aerosol and include solid
particles of carbon, activated charcoal, carbonaceous resin derived by
pyrolysis,
silica, chemically activated derivatives of carbon and silica, metal based
catalysts and mixtures thereof.
Flavourants add desirable sensory properties to the aerosol and can be present
in the tobacco-derived portion, the filter portions and combinations thereof.
Common flavourants include menthol, mint, peppermint, vanilla, liquorice,
fruit
extracts, esters, acetals, fructals and combinations thereof. Flavourants can
be
present within the filter matrix, the tobacco-derived material, in a flavour
thread,
in beads, breakable capsules, non-breakable capsules, encapsulated within a
protective matrix, encapsulated within a molecule including cyclodextrin and
combinations thereof.
Aesthetic elements include colourants dispersed within the filter matrix or
localised within a specific region and filters shaped to form a distinct
pattern,
logo, or are recessed or fluted or is combination thereof. This is represented
in
Figure 3 which shows an example filter component providing a mouthend with a
recessed portion 10. In conjunction with the component 7 can provide a mouth
filter portion 3 with the recess 10 in it for use in the article. This
structure
.. provides an aesthetically pleasing construction that can contribute to
product
strength by employment of the layered overwrap 4. It also allows the
possibility
of provision of a shorter filter component 7 which can reduce total pressure
drop.
With such an example the filter portion 7 will generally be 6 mm in length or
longer to ensure it retains material in the tobacco portion 2 that still
provides
appropriate structural integrity whilst controlling pressure drop and
compressibility for the overall article.
Figures 7 and 8 depict usage of the current invention with an electronic
cigarette
as the aerosol-generating device. The device utilises a battery power source
14
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to heat a resistive wire 17 in order to volatilise an e-liquid from reservoir
16, the
liquid is typically nicotine-free. The article of the invention 19 is inserted
into the
electronic- cigarette device at point 18. The first aerosol produced by
resistive
wire 17 passes through article 19 and is modified to produce the inhalable
aerosol 20. The modification to the first aerosol includes the addition of
nicotine
and other flavourants from the present invention. The modification can also
include the removal of undesirable chemical components via attenuants and the
removal of undesirable aerosol and other particles from the aerosol.
In an alternative embodiment, the first aerosol additionally contains
chemicals to
assist the incorporation of desirable chemicals from the tobacco derived
portion
2 into the aerosol. Preferably the first aerosol contains volatile acids which
act to
incorporate freebase nicotine from the tobacco derived portion 2 and thereby
enhance the amount of nicotine in the inhaled aerosol. Suitable volatile acids
include ascorbic, pyruvic acid and levulinic acid.
Figure 10 shows an alternative use of the current invention, whereby the
current
invention is inserted into a device with power source 14 which uses a heat-
source 23 to directly heat the tobacco portion 2. The action of the heat from
the
associated device releases volatile components from the invention which form
the inhalable aerosol. Heat source 23 includes one of electrically driven or
chemical reaction driven heating means. Electrically driven options include
metallic heating elements, resistive wire, thin film heaters, ceramics heaters
and
combinations thereof in conjunction with a battery or cell. Alternatively, an
electrically driven heat-source 23 can rely upon induction, where an
alternating
electromagnetic field is produced which in turn generates heat in a suitably
placed susceptor element 24. The efficiency of induction is improved when the
susceptor element 24 is in close proximity to the material to be heated,
therefore
the susceptor element 24 is best placed within the tobacco derived material or
as part of the overwrap in contact with the tobacco derived portion. In the
case
of induction heating the power source and circuitry may be configured to
operate
at a high frequency. Preferably, the power source and circuitry may be
configured to operate at a frequency of between approximately 80 kHz and 500
kHz, preferably approximately 150 kHz and 250 kHz, more preferably
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approximately 200 kHz, and the assembly may be arranged to operate in use
with a fluctuating electromagnetic field having a magnetic flux density of
between
approximately 0.5 Tesla (T) and approximately 2.0 T at the point of highest
concentration. Whilst the induction coil may comprise any suitable material,
typically the induction coil may comprise a Litz wire or a Litz cable. The
susceptor may comprise one or more, but not limited, of aluminium, iron,
nickel,
stainless steel and alloys thereof, e.g. nickel chromium. With the application
of
an electromagnetic field in its vicinity, the susceptor may generate heat due
to
eddy currents and magnetic hysteresis losses resulting in a conversion of
energy
from electromagnetic to heat.
Chemical reaction driven heat sources include combustion, oxidation, redox and
other exothermic reactions.
Humectants are additives that act to retain water within a matrix and include
polyols such as propylene glycol, glycerol, PEGs of various molecular weights,
sugar alcohols such as sorbitol and combinations thereof. Within the present
invention volatilised humectants also function to produce aerosol droplets.
Preferably the humectant is a mixture of propylene glycol and glycerol.
pH modifying agents include acids, bases and buffers which can be used to
alter
the ionisation state of chemicals within the tobacco derived portion thereby
modifying their volatility. Notably free base nicotine which predominates at
alkaline pH is significantly more volatile than nicotine salts which
predominate at
acidic pH. In a preferred embodiment sufficient basic agents are added to the
tobacco derived portion to achieve an overall pH>7 rendering more nicotine
available to be volatilised into the inhalable aerosol. More preferably the
overall
pH is >8. Suitable basic agents include metal carbonates, metal hydrogen
carbonates, metal hydroxides and ammonium salts.
In one embodiment of the present invention the tobacco derived portion 2 is
generated by providing a blend of tobacco grades comprising flue cured and air-
cured tobaccos with a chemical composition in accordance to Gothiateke
Standard, namely tobacco-specific nitrosamine (NNN + NNK) content of
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<1mg/kg and benzo[a]pyrene content of <1.25ug/kg. Once blended, the tobacco
is reduced in size by first shredding and then grinding to pass through a
No.18
Mesh giving a particle size of =<1mm. To the ground tobacco is added 50%
equivalent mass of deionised water; 2% equivalent mass of flavourant - a 50:50
5 mix of menthol and mint oils; 0.375% equivalent mass pH modifying agent -
sodium hydroxide. The resultant tobacco paste is passed through a Coperion
extruder with barrel temperature 25000 and pressure 4atm linked to a
pelletizer
to produce a shaped material of particle size approximately 1.5mm diameter.
The tobacco derived particles are then dried under vacuum to <10% moisture.
10 The dried tobacco particles are then sieved to produce a fraction in the
range
0.2mm - 1.25mm. The mouth end and distal end filter portions 1,3 are
manufactured using a Hauni filter rod making machine. Filter portions 1,3 are
made from cellulose acetate tow 6Y17 using 10.1mg of tow per mm of filter
length; plasticised with 12% weight/weight triacetin, 26g5m, 20000U plugwrap
15 affixed with PVA glue. Final filter portion dimensions are 8mm diameter
and
6mm length. The assembly of the non-combustible tobacco article is carried out
on a Molins cavity filter machine using a paper overwrap PPW 35 by SWM with
a 0.1% coating of AKD on the inner surface. The construction of the article is
6mm filter portion, 17mm cavity with 250mg tobacco-derived material, 6mm
filter
portion affixed with PVA glue. This generates a final article with a total
pressure
drop of 40-65mm water column and compressibility factor of -3% in the
longitudinal axis.
With the present invention, by controlling the compressibility of the article
it is
possible to provide a device which is easy for a user to handle and remove
from
a vapour generating device without deformation or damage even though the
generation of vapour during use will potentially deteriorate the mechanical
properties of the article. By optionally controlling draw pressure it is
possible to
ensure a pressure drop that a user is comfortable in creating the draw
pressure
when receiving vapour. In addition, the invention ensures that an article to
hold
an appropriate of vapour generating material can be provided in an article
which
is aesthetically pleasing and simple and straightforward to manufacture.
