Note: Descriptions are shown in the official language in which they were submitted.
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Filter Additive
The invention relates to methods for making filter elements and filters for
smoking
articles, the filter elements and filters comprising an additive material. In
particular,
the invention relates to methods of incorporating an additive which is solid
at room
temperature into filter material, the method comprising the step of melting
the
additive material.
A wide variety of materials have been used as filter materials for tobacco
smoke.
The most commonly used filter material is cellulose acetate tow. However,
whilst
cellulose acetate has an excellent capacity to filter tobacco smoke, it has
the
drawback that it is slower to degrade than other materials and can therefore
be
disadvantageous environmentally.
Filter materials made from non-woven sheet material and paper are known.
Suitable sheet materials include polyvinyl alcohol, reconstituted tobacco,
starch, and
polylactic acid. These materials are much more readily degradable than
cellulose
acetate tow, however, they have drawbacks. In particular, in order to attain
the
desired structural rigidity when constructing a filter element from non-woven
sheet
materials and paper, the filter material is generally densely packed and this
means
that these filter elements have quite different properties to those made of
cellulose
acetate. They exhibit a greater resistance to the flow of smoke, resulting in
a
pressure drop which is higher than that of a conventional cellulose acetate
(CA)
filter, requiring the user to draw harder on the smoking article. Perhaps more
significantly, the smoke drawn through such filter material has been found to
have
different taste characteristics compared to the smoke drawn through
conventional
cellulose acetate filter material. What is more, filter elements comprising
non-
woven sheet materials or paper as the filter material have been shown to
exhibit
significantly less selective removal of semi-volatile compounds than
conventional
cellulose acetate tow filter materials.
It is known to use additives such as triacetin (glycerin triacetate), TEC
(triethyl
citrate) and PEG 400 (low molecular weight polyethylene glycol) in cellulose
acetate
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filters. These additives function as plasticizers and they are generally used
in cellulose
acetate filters to give the filter rods sufficient hardness for cigarette
manufacture and use.
Some plasticizers have the additional advantage of providing cellulose acetate
tow with an
improved capacity to selectively remove semi-volatile compounds such as
phenol, o-
cresol, p-cresol and m-cresol from tobacco smoke.
These plasticizers are in liquid form at room temperature and they are sprayed
on to
cellulose acetate tow. The plasticizer coats the individual fibres within the
tow and, with
time, they bind or fuse adjacent fibres together at their points of contact,
thereby
increasing the hardness or rigidity of the filter material, to give the core
of the filter the
desired structural strength. The mode of action of the plasticizers does,
however, mean
that there is an upper limit to the amount that may be incorporated into
cellulose acetate
tow filter material. When above about 7% of plasticizer by weight of the
filter is included,
the plasticizer starts to have a detrimental effect on the cellulose acetate
tow, forming
holes which compromises its filtration properties.
Whilst inclusion of plasticizers such as triacetin, TEC or PEG 400 in CA
filters is
relatively common, their inclusion in non-woven sheet and paper filter
materials is less
attractive. Firstly, the plasticizers are used in CA filters to bind fibres
and the plasticizer
would clearly not have this advantageous effect when added to non-woven sheet
material
or paper (in which the fibres are already bound within the sheet structure).
Secondly,
these commonly used plasticizers are liquids and their application to non-
woven sheet and
paper filter materials will be limited as they will cause these materials to
become soggy and
to lose their structural integrity. Paper, the most commonly used sheet filter
material, may
start to disintegrate when moist, and will therefore have a reduced
acceptability to the
user. Furthermore, many sheet materials, including polyvinyl alcohol and
polylactic acid,
are soluble and therefore the addition of aqueous additives may result in the
partial
dissolution of the material.
The present invention provides a method of constructing a filter element which
is more
readily degradable than filter elements comprising a conventional cellulose
acetate tow as
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the filter material. Preferably, the method will also result in a filter
element which exhibits
an improved capacity to selectively remove semi-volatile compounds and which
provides
smoke having similar taste characteristics to that provided by conventional
cellulose
acetate filters.
Summary of the Invention
According to a first aspect of the present invention, a method for making a
smoking
article filter element is provided. The method comprises the steps of:
i) applying an additive which is solid at room temperature to the filter
material;
ii) heating the additive so as to melt it; and
forming the filter material and additive into a filter element.
The steps of the method may be carried out in any order, although in some
embodiments,
step i) is preferably carried out before step iii).
According to a second aspect of the present invention, a filter element for a
smoking
article is provided. The filter element comprises filter material and an
additive which is
solid at room temperature, the filter element being obtained or obtainable by
the method
according to the first aspect of the present invention, wherein the sheet
filter material
comprises one of paper, reconstituted tobacco, and starch.
According to a third aspect of the present invention, a filter for a smoking
article is
provided, comprising a filter element according to the second aspect.
According to a fourth aspect of the present invention, there is provided a
smoking article
comprising a filter element according to the second aspect and/ or a filter
according to
the third aspect, attached to a rod of smokeable filler material. The
smokeable filler
material may comprise tobacco and the smoking article may be a cigarette.
As used herein, the term "smoking article" includes smokeable products such as
cigarettes, cigars and cigarillos whether based on tobacco, tobacco
derivatives,
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expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-
not-
burn products.
Detailed Description of the Invention
The present invention relates to a method of producing a filter element for
inclusion in a smoking article, the method comprising applying an additive to
filter
material, the additive being solid at room temperature and the method
involving
heating the additive so that it melts.
In one embodiment of the invention, the additive is applied to the filter
material in
solid form, for example in the form of a powder, prior to formation of the
filter
rod. The formed filter rod may then be heated to melt the additive whilst it
remains
in contact with the filter material. When the additive material subsequently
cools
and re-solidifies, it provides the filter material and the filter element
formed with
one or more of: stability and rigidity; improved smoke taste characteristics;
and
improved selective removal of semi-volatile compounds.
In an alternative embodiment of the invention, the additive is melted and
applied to
the filter material in molten or liquid form, prior to formation of the filter
rod.
When the additive material subsequently cools and re-solidifies, it provides
the filter
material and the filter element formed with one or more of: stability and
rigidity;
improved smoke taste characteristics; and improved selective removal of semi-
volatile compounds.
The methods according to the present invention may be used to add an additive
to
any type of filter material, including fibrous filter material or tows, such
as
conventional cellulose acetate tow which is currently widely used in smoking
article
filters. However, the method is considered to be particularly effective when
it is
used to add an additive to alternative filter materials, such as those
constructed
from a sheet material, for example non-woven sheet materials or paper.
Paper filter material usually comprises gathered, pleated, crimped, crepe or
even
shredded paper. Paper filter materials tend to have a low air permeability,
exhibit a
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basic pH, and can be gathered or formed easily to form the filter element. A
preferred filter material for filter elements of the present invention is a
gathered or
pleated paper. Examples of suitable papers are PuracelTM and MyriaTM papers
(Filtrona plc, United Kingdom).
Other, non-woven sheet materials may be used as filter materials. Non-woven
materials are broadly defined as sheet or web structures bonded together by
entangling fibres or filaments mechanically, thermally or chemically, or by a
combination of two or more of these. They tend to be flat, porous sheets that
are
made directly from separate fibers. They are not made by weaving or knitting
and
do not require converting the fibers to yarn. The non-woven sheet materials
used
in the present invention are preferably ones which are readily biodegradable.
Examples of materials include polyvinyl alcohol (PVOH), polylactic acid or
polylactide (PLA), poly(e-caprolactone) (PCL), poly(1-4 butanediol succunate)
(PBS)
and poly(butylene adipate-co-terephthalate) (PBAT). Other suitable filter
materials
include starch fibres and calcium alginate.
Non-woven sheet materials and paper are more readily biodegradable than
cellulose
acetate tow. However, they currently have drawbacks when used as filter
materials.
In order to attain the desired structural rigidity when constructing a filter
element
from non-woven sheet materials and paper, the filter material must be very
densely
packed and this means that these filter elements have quite different
properties to
those made of cellulose acetate. They exhibit a greater resistance to the flow
of
smoke, resulting in a pressure drop which is higher than that of a
conventional
cellulose acetate filter, requiring the user to draw harder on the smoking
article.
The sheet material used in the method of the invention may comprise paper,
polyvinyl alcohol, reconstituted tobacco, starch, or polylactic acid.
Preferably the
sheet filter material is paper.
Preferred non-woven sheet materials have a thickness greater than about 0.05
mm,
preferably from about 0.06 mm to about 0.08 mm. The paper filter materials may
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comprise paper having a basis weight of about 15g/m2 to about 40g/m2,
preferably
about 20g/m2 to about 35g/m2.
The sheet material used in the method of the invention may additionally or
alternatively comprise polyvinyl alcohol (PVOH). PVOH is unique in being the
only
biodegradable, carbon-carbon backbone polymer that can completely biodegrade
to
small molecules, e.g., carbon dioxide and water.
The method may comprise the use of the sheet material polylactic acid. The
lactate
from which PLA is produced can be derived from the fermentation of
agricultural
by-products.
However, because of the hygroscopicity of PVOH and PLA, prior art attempts to
process such materials have resulted in filter rods which are too soft to be
efficiently handled in high speed cigarette manufacturing machines.
Furthermore,
cigarette filter elements formed from PVOH and PLA have failed to provide a
sufficiently stable porous matrix to permit proper draw characteristics and
avoid
collapse in use. Using the method of the present invention to apply additive,
the
qualities of these sheet materials may be modified to make them suitable for
use in
filter elements.
In contrast to the use of additives which are liquid at room temperature (such
as the
plasticisers frequently used in conventional cellulose acetate filters,
including low
molecular weight PEG, triacetin and TEC), an additive which is solid at room
temperature may provide firmness and rigidity to the filter without damaging
the
filter material by making it soggy.
Indeed, rather than weakening a non-woven sheet or paper filter material, the
method of the present invention uses a solid additive which has been melted,
but
which re-solidifies at room temperature and bonds parts of the filter material
together. Therefore, the additive has the benefit that it can actually
increase the
structural integrity and rigidity of the filter material. In the case of sheet
filter
materials, addition of a solid additive by a method according to the present
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invention may make it possible to use less of the filter material in the
filter element.
This provides further flexibility when forming the filter element with regard
to the
amount of filter material required to achieve the desired hardness and
rigidity. This
in turn would allow the manufacturer to adjust the pressure drop of the filter
element. This would allow a filter element according to the present invention
to be
designed having properties which closely resemble those of conventional CA
filter
elements.
Thus, the addition of a solid additive to the filter material by the methods
according
to the present invention can eliminate the shortcomings that are currently
associated
with the use of sheet filter materials, by improving the rigidity of the
filter,
improving the taste of the smoke, and increasing the selective removal of semi-
volatile compounds. Furthermore, the combination of filter material and solid
additive may provide vastly improved disintegration, dispersion and/or
biodegradability of the filter element.
The methods of the invention allow the properties of non-woven sheet and paper
filter materials to be fine-tuned, so that the performance of the filter
element can
more closely resemble that of a cellulose acetate filter element. These
additives also
give the use of sheet filter material much greater flexibility, widening the
range of its
applicability whilst retaining the beneficial biodegradable properties.
In one embodiment of the invention, the additive comprises a high molecular
weight polyethylene glycol which is solid at room temperature. Suitable PEGs
include PEG 600 and higher, and preferably PEG 1000 and higher.
High molecular weight polyethylene glycol has the additional advantage of
providing
selective removal of semi-volatile compounds. This selective removal of semi-
volatile compounds provided by the addition of the PEG to the filter element
is
proportional to the amount of PEG included. The methods of the present
invention, which involve the use a PEG which is solid at room temperature (in
contrast to the PEG previously used in filters) provide flexibility which
allows the
addition of greater amounts of PEG than would be possible if using a liquid
PEG.
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This means that the ability of the filter element to selectively remove semi-
volatile
compounds may easily be adjusted to a desirable level. This is in contrast to
the
situation where low molecular weight PEG is added to cellulose acetate filters
as a
plasticizer. Cellulose acetate filters are generally disclosed as including
less than
10% plasticizer because including higher levels of plasticizer than this has a
detrimental effect on the cellulose acetate tow, causing holes to be formed.
Consequently, the amount of plasticizer available to provide selective removal
of
semi-volatile compounds in cellulose acetate filters is limited.
According to the method of the invention, PEG may be included in the filter
material of the filter element in an amount of up to about 30%, preferably up
to
about 20%, and more preferably about 5-10% by weight of the filter element.
As PEG is water-soluble, its inclusion in the filter elements should not
adversely
affect the biodegradation of the product. Indeed, it has been surprisingly
found that
the addition of PEG to a filter element comprising a non-woven sheet material
or
paper as the filter material actually enhances biodegradation.
A study was conducted to assess the effect of the use of a paper filter
material and
additives on biodegradability. Degradation of cigarette butts under
environmental
conditions was assessed. The samples used included a filter with PuracelTM
(7mg)
with no additive and a filter with PuracelTM with 7% PEG 400. The results show
that the inclusion of the PEG as an additive significantly increased the rate
of
biodegradation of the butts on a grass surface. It is speculated that this may
have
been due to the presence of microorganisms, insects and the like, which fed on
the
butts and the presence of the PEG additive made some butts more attractive. It
is
anticipated that a similar effect will be observed upon use of a high
molecular
weight PEG as an additive.
Other additives which may be used in the methods of the present invention
include
high molecular weight methoxypolyethylene glycols (MPEGs), such as MPEG 750,
1000, 2000, 3000 and 5000; and waxes which are solid at room temperature,
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including beeswax, carnauba, shellac, castor wax, paraffin and various
synthetic
waxes.
If desired, the method can further comprise the incorporation into the sheet
filter
material of further additives such as tobacco extracts, glycerine, menthol,
carbon
fibres, carbon particles, and the like.
A further advantage of the method of the invention is that filter elements to
which
additive has been applied using the claimed method are more stable to the
subsequent addition of additives, including liquid additives. Other additives,
including liquid additives, which would otherwise have been difficult to apply
to
sheet material without making it soggy, can be added to the filter rod to
adjust the
properties of the filter as required, or provide further qualities to the
filter element,
such as flavourants for enhanced flavour.
Methods according to the present invention encompass different ways of
applying
the additive to the filter material.
In one embodiment, the method involves applying the additive to the filter
material
in liquid form. In order to do this, the additive must be heated and is
sprayed or
otherwise applied to the filter material before the filter material is formed
into the
filter rod or core of the filter element.
This embodiment is attractive because it necessitates relatively little
modification of
conventional filter-making machinery. The only real change is the provision of
means for heating the additive so that it is in molten form and may be applied
to the
filter material in that form. The application of the heat is relatively easy
to control
and monitor. Also, the application of heat is primarily just to the additive
and so
other components of the filter element do not need to be exposed to localised
heat.
This method is applicable to both fibrous tow filter materials as well as to
non-
woven sheet materials and paper. Although such sheet materials are being fed
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under some tension, the application of the liquid additive does not weaken the
sheet
structure sufficiently to cause a problem.
In an alternative embodiment, the method involves applying the additive to the
filter material in solid form, for example in the form of a powder, before the
filter
material is formed into the filter rod or core of the filter element. Once
formed, the
filter rod is heated to melt the additive. The additive melts and subsequently
re-
solidifies, bonding the filter material without making it soggy.
This method allows the additive to be applied to the filter material in a
controlled
and uniform manner, and with minimal wastage of additive material. It also
avoids
any potential disadvantages associated with applying a liquid to the filter
material.
For example, in the case of sheet filter materials, this embodiment avoids the
potential weakening of the sheet structure by applying a liquid.
Where the solid additive is being applied to a sheet material, such as the non-
woven
sheet materials and papers discussed herein, steps will need to be taken to
ensure
that the solid additive remains in contact with the sheet filter material
whilst the
sheet is being fashioned into a filter rod. This may require the application
of some
adhesive or special orientation of the sheet material.
Filter elements comprising sheet materials are generally manufactured using a
process which comprises the steps of crimping the sheet material and then
gathering
the sheet material to form a cylindrical filter rod. The additive may be added
prior
to or during the crimping process, or may be added to the sheet material after
it has
been crimped. The additive may even be added to the crimped material as it is
gathered to form the filter rod, with the effect that it is immediately
contained
within the rod and does not need to be adhered.
The additive may be adhered to the filter material using any suitable
adhesive, for
example, using liquid starch adhesives, or EVA and PVA adhesives.
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The solid additive may be applied to sheet filter material as a powder or in
larger
pieces, such as in the form of flakes or pellets.
The additive may be applied to the filter material by any suitable method that
is
known to the skilled person. For example, powdered additive may be sprayed on
to
the filter material, or it may be applied by an applicator which may or may
not be in
direct physical contact with the filter material. The additive may be loosely
applied
to the filter material, for example by being sprayed or sprinkled, or may be
applied
using a degree of force, such as by being pressed or smeared on to the filter
material.
In a particular embodiment, the filter material is formed with the solid
additive
embedded in or on it. Applying the additive which is solid at room temperature
to
the filter material in this way can simplify the methods of the present
invention.
Once the filter material has been formed into the filter rod, the rod may be
heated
to melt the additive, and then allowed to re-solidify.
It is known to add various materials in or on sheet materials such as non-
woven
sheet materials and paper. For example, the additive may be applied to the
sheet
material during its manufacture or as part of a post-manufacture processing
step. In
this way, the additive may be incorporated within the sheet, or as a coating
on one
or both sides of the sheet material. The additive may be uniformly present
within or
on the surface of the sheet, or may be present in discreet areas, such as in
patches
or strips on the sheet material.
Fibrous filter material may also be prepared with particles of solid additive
material
dispersed throughout the fibres. Such particles may need to be adhered to the
fibres. Alternatively, they may become trapped between adjacent fibres if the
fibrous material is dense enough.
Where the additive is applied to the filter material in liquid form, the
heating step of
the method of the invention involves applying sufficient heat to the additive
to
ensure that the additive is molten to the extent that it has a viscosity
suitable for the
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mode of application chosen. The molten or liquid additive may be sprayed or
printed, or the filter material may be submerged in the liquid additive.
According to one embodiment, a system for applying molten or liquid additive
to
filter material comprises a heated chamber in which the additive is maintained
in
liquid form, a pump, and a hose with one or more nozzles configured to spray
droplets onto the filter material prior to formation of the filter.
A number of application systems are known which are suitable for applying
molten
or liquid additive to filter material. Such systems are available, for
example, from
SPI Developments, C. B. Kaymich & Co. Ltd, or Kohl Maschinenbau GmbH.
Where the additive is to be melted after the filter material has been formed
into a
rod or core, sufficient heat needs to be applied to ensure that all of the
additive,
which is dispersed throughout the rod, is melted.
The application of heat to the formed filter rod must be carried out with
care, as it
may have a detrimental effect on other components of the filter rod, including
the
filter material and any wrapper (which is likely to be paper and could be
singed or
scorched by exposure to high temperatures).
Obviously, the temperature that the filter rod must be heated to, and the
duration
of heating, is dependent upon the melting point of the additive. A preferred
additive, PEG 1000, has a melting point of around 37 C, and therefore in this
case,
the filter rod is heated to a temperature exceeding 37 C. The filter rod may
be
heated to a temperature exceeding 40 C, preferably exceeding 45 C, and most
preferably exceeding 50 C. In addition, the heat needs to be applied for a
period
sufficient to ensure that the whole rod is heated and not just the outer
areas.
Heat may be applied using any suitable means. For example, the filter rod or
filter
element may be brought into close proximity with a heating element.
Alternatively
or additionally, the filter rod or filter element may be heated by means of a
current
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of hot gas, such as hot air or steam, or via the application of radiation,
such as
microwave radiation.
Heat may be applied to the filter rod as soon as it is formed. In other words,
heating of the filter rod may occur at some stage between formation of the
filter rod
at the garniture and the cut-off, where the filter rod is separated into
sections.
Heating of the rod will generally be for a very brief period, such as less
than 1
second, due to the linear motion of the rod through the machine. Clearly,
since
filter rods are currently formed without a heating process, then concomitant
forming and heating of the filter rod may require expensive modification of
the
current apparatus.
For this reason, the filter rod is preferably heated at a later stage, and
this may be
achieved using a heater which is essentially separate from the apparatus
involved in
forming the filter rod. The heating is preferably carried out in a separate
conditioning step, where lengths of filter rod are kept at an elevated
temperature for
an extended period of time to ensure that all of the additive is melted and
bonds to
the filter material.
The method of the invention may further comprise wrapping the filter rod in a
suitable wrapper such as a plugwrap. In this case the heat may be applied
before the
filter rod is wrapped. Alternatively, the filter rod may be wrapped and then
heated.
According to some embodiments, the assembled filter is heated to melt the
additive,
although this approach can be complicated by the insulating properties of the
filter
material. In addition the speed of filter manufacture means that the time
available
for heating the filter is limited. Having said that, heating of the assembled
filter may
be achieved in various ways. For example, the filter rod may be exposed to
heat by
conductance, such as on a heated drum in the presence of hot air.
Alternatively,
trays of filter rods (such as 4,000 filters per tray) may be passed through a
heated
tunnel or similar arrangement, in the presence of hot air. The filter trays
may
alternatively be heated by the application of radiation such as microwave
radiation.
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The methods of the present invention may further comprise a step of
incorporating
particulate material into the filter element. Suitable particulate material
includes
sorbents (e.g. selected from activated carbon, charcoal, silica gel,
sepiolite, alumina,
ion exchange material etc.), pH modifiers (e.g. alkaline materials such as
Na,COõ
acidic materials), flavourants, other solid additives and mixtures thereof.
Advantageously, the particulate material may be selected from a group of
relatively
high surface area materials capable of adsorbing smoke constituents without a
high
degree of specificity. Suitable general adsorbents can be selected from the
group
consisting of carbon, activated carbon, activated charcoal, activated coconut
carbon,
activated coal-based carbon or charcoal, zeolite, silica gel, meerschaum,
aluminium
oxide (activated or not), carbonaceous resin or combinations thereof.
One type of particulate material which may be used in the method of the
invention
is carbon, for instance activated carbon, or charcoal or other carbonaceous
absorbent material. The preferred type of activated carbon is activated
coconut
carbon.
The particulate material may be incorporated into the filter element in such a
way
that it is interspersed throughout the filter element, or it may be
interspersed in
some parts (but not all) of the filter element. The particulate material may
be
interspersed over the full longitudinal length of the core. Alternatively, the
particulate material may be interspersed from one end of the core to a section
that
is short of the other end. Alternatively, the particulate material may be
present in
discrete areas that need not extend from ¨ or be present at ¨ any end of the
core.
Different areas may have different loadings of particulate material and/or
different
types of particulate material.
The methods of the present invention may further comprise wrapping the filter
element in a suitable wrapper.
The wrapper of the filter element is preferably a paper wrapper, and most
preferably
comprises conventional plugwrap, such as plugwrap having a basis weight of
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between about 20g/m2 and about 35g/m2, preferably about 27g/m2. The plugwrap
may be porous or non-porous.
The method may comprise the use of a wrapper which includes a particulate
material adhered to one or more portions of its surface. Preferably, the
particulate
material is adhered to two or more portions of the wrapper, the portions being
circumferentially spaced from one another, with at least one of the portions
extending over the full longitudinal length of the wrapper.
The smoking article filter element produced according to the method of the
present
invention may be incorporated into a smoking article filter.
The smoking article filter may comprise a single filter element of the method
of the
invention. Alternatively, the smoking article filter may include two or more
filter
elements produced according to the method of the invention. In other words,
the
filter element may be part of a composite (or multi-component) filter.
Suitably the
filter elements of the composite filter are arranged longitudinally of one
another
with the end of each filter element abutting the next. The composite filter
may have
2, 3, 4 or more distinct or discrete sections. In one embodiment the filter is
a triple-
filter with three sections. In another embodiment the filter is a dual-filter
with two
sections.
The filter sections of the composite filter may be identical, or
alternatively, one or
more of the sections may have a composition which is different to that of the
other
section or sections. For example, in some embodiments, one or more of the
sections may optionally comprise: (i) cellulose acetate filter material; (ii)
a
biodegradable filter material, such as crepe, crimped or gathered paper
material; (iii)
one or more additives, such as adsorbent or flavouring materials, which may be
encapsulated; and/or, (iv) a cavity, which may comprise granular material such
as
adsorbent material.
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The smoking article filter element produced according to the method of the
present
invention may be incorporated into a smoking article. The filter element may
be in
the form of a smoking article filter as described above.
The filter element and/or filter comprising the filter element may be attached
to a
wrapped smokeable filler material rod (i.e. a wrapped tobacco rod, for
instance) by
conventional tipping overwrap to form the smoking article, which may be a
cigarette.
Suitably, the smokeable filler material may be tobacco material or a tobacco
substitute material. Preferably the smokeable material is a tobacco material.
Suitably
the tobacco material comprises one or more of stem, lamina, and tobacco dust.
It is
preferred that the tobacco material comprises one or more of the following
types:
Virginia or flue-cured tobacco, Burley tobacco, Oriental tobacco,
reconstituted
tobacco. It is much by preference that the smokeable material comprises a
blend of
tobacco material.
The smokeable filler material may also comprise one or more of the following:
burn
additive, ash improver, inorganic filler material, organic filler, aerosol
generating
means, binder, flavouring and/or colouring agents.
The tipping overwrap may be ventilating or non-ventilating overwrap.
Various modifications and variations of the described methods and system of
the
present invention will be apparent to those skilled in the art without
departing from
the scope of the present invention. Although the present invention has been
described in connection with specific preferred embodiments, it should be
understood that the invention as claimed should not be unduly limited to such
specific embodiments. Indeed, various modifications of the described modes for
carrying out the invention which are obvious to those skilled in the art are
intended
to be within the scope of the following claims.
