Note: Descriptions are shown in the official language in which they were submitted.
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FILTER FOR A SMOKING ARTICLE
The present invention relates to filters for smoking articles.
It is well known that filtration of smoke in a smoking article, such as a
cigarette may
affect the taste and flavour characteristics of a product when smoked. Filters
commonly
include adsorbent materials, such as activated carbon, to reduce certain
components of
the smoke during smoking. However, activated carbon in a filter can adversely
affect
the taste and/or flavour characteristics of a cigarette.
Therefore, in a first aspect of the invention, there is provided a filter
element for a
smoking article, the filter element comprising a plug of filter material, a
tobacco core
extending substantially longitudinally through the plug of filter material,
and wrapping
means wrapped around at least a portion of a longitudinally extending surface
of the
tobacco core.
The inventors have found that the provision of the substantially longitudinal
tobacco
core improves the flavour of smoke (which comprises gas and particulate
matter) that is
inhaled by a smoker. Furthermore, the provision of the wrapping means ensures
that
the tobacco remains within the core within the plug of filter material, and
that the
smoke is directed therealong.
Preferably, the tobacco core extends substantially longitudinally between
mutually
opposing end faces of the plug of filter material. Preferably, the tobacco
core extends
in a direction which is substantially parallel to a side face of the plug of
filter material,
which side face is preferably substantially perpendicular to one or both end
faces.
Preferably, the tobacco core extends through an inner portion of, and is
surrounded by,
the filter material. Preferably, the tobacco core extends through
substantially the =centre
of the plug of filter material.
Advantageously, the tobacco core is disposed in close proximity with the path
of the
gaseous flow as it moves through the filter element, and is therefore able to
affect
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various characteristics of the gaseous flow before the flow reaches the
smoker's mouth.
Furthermore, because the tobacco core is disposed substantially longitudinally
within
the plug of filter material, it does not adversely affect the direction or
rate of gaseous
flow, and so the smoker does not detect a significant difference in the
resistance to
draw therethrough.
The tobacco core may comprise shredded tobacco, powdered tobacco,
reconstituted
tobacco, tobacco stem, tobacco fibres, tobacco sheet and/or cut tobacco.
However,
preferably the tobacco core comprises cut tobacco lamina, cut tobacco blend
and/or
tobacco stem.
The tobacco core may form a tobacco rod of any cross-section. For example, the
tobacco core may form a tobacco rod of triangular or square cross-section.
However,
preferably the tobacco core forms a tobacco rod of circular cross-section.
Hence, the
tobacco core may be substantially cylindrical in shape.
The wrapping means may be substantially permeable to air, such that smoke may
pass
therethrough in to the tobacco core as a smoker inhales. The wrapping means
may be
formed of any conventional paper material. For example, the wrapping means may
comprise plugwrap or paper, for example cigarette paper. The wrapping means
may be
perforated. The wrapping means may be a reconstituted wrapper, or a tobacco
sheet
wrapper. The wrapping means may comprise tobacco leaf. The wrapping means may
be impervious.
The wrapping means may be in contact with substantially all of the
longitudinally
extending side surface of the tobacco core. Preferably, the wrapping means
circumscribes the tobacco. However, the wrapping means may not be disposed
around
at least one end face, and preferably each end face, of the tobacco core.
The tobacco core may comprise, or be derived from, at least a longitudinal
section of a
tobacco rod of a smoking article, such as a cigarette, cigar or cigarillo, or
the like, i.e. the
smokeable section of the smoking article. It will be appreciated that the
longitudinal
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section of the tobacco rod will comprise a wrapper, such as cigarette paper or
the like,
and that this wrapper forms the wrapping means of the filter element of the
first aspect.
It is preferred that the diameter of the longitudinal section of the tobacco
rod is less
than the diameter of the plug of filter material, and hence filter element
according to
the first aspect, such that it forms the tobacco core extending therethrough.
Standard-
sized cigarettes tend to have a diameter of about 7.5mm to about 9.5mm
(preferably 8-
12mm), whereas slim-sized cigarettes tend to have a diameter of about 2-6mm.
Therefore, because the diameter of the tobacco rod of a slim-sized cigarette
is less than
that of a standard-sized cigarette, the inventors envisage using a
longitudinal extending
section of the tobacco rod of a slim-sized smoking article to form the wrapped
tobacco
core of a filter element for use in filter of a standard-sized smoking
article. The
inventors believe that they are the first to consider using the tobacco rod
section of a
slim-sized smoking article to form a tobacco core in the filter of a standard-
sized
smoking article.
Hence, in a second aspect of the invention, there is provided a filter element
for a
smoking article, the filter element comprising a plug of filter material, and
a tobacco
core extending substantially longitudinally through the plug of filter
material, wherein
the tobacco core comprises, or is derived from, a longitudinal section of a
tobacco rod
of a smoking article.
The tobacco core may comprise, or be derived from, a longitudinal section of a
tobacco
rod of a slim-sized smoking article. By using a longitudinal section of a
wrapped
tobacco rod of a slim-sized smoking article, the manufacture of standard-sized
filter
elements may be facilitated. Furthermore, advantageously, it is easier to
change the
tobacco in the longitudinal core extending through the filter material,
thereby providing
different tobacco styles and tastes in a range of filter elements.
It will be appreciated that there are many different types of slim-sized
smoking articles
from which the tobacco core may be derived, and that the dimensions of such
slim-
sized smoking articles varies from brand to brand. However, the tobacco core
in the
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filter element of the first or second aspect may be between 3mm and 8mm in
diameter,
preferably between 3mm and 7mm in diameter, more preferably between 3.5mm and
6.5mm in diameter, and most preferably between 4mm and 6mm in diameter.
Once prepared, the tobacco core may be encased by filter material to form the
filter
element of the first or second aspect. The plug of filter material may
comprise any
suitable filter media, which will be known to the skilled technician. A
preferred filter
material comprises cellulose acetate. The diameter of the plug of filter
material may be
between 5mm and 15mm, preferably between 6mm and 12mm, more preferably
between 7mm and 10mm, and most preferably between 7mm and 9mm.
Preferably, the ratio of the diameter of the plug of filter material to the
diameter of the
tobacco core is between 0.5:1 and 10:1, more preferably between 1:1 and 5:1,
even
more preferably between 1:1 and 3:1, and most preferably between 1.5:1 and
2:1.
The filter element of the first or second aspect may comprise a flavourant. In
embodiments where a flavourant is used, the flavourant may be incorporated in
the
plug of filter material. However, preferably the flavourant is incorporated in
the
tobacco core. For example, flavourant may be sprayed onto the tobacco material
prior
to formation into a rod.
It will be appreciated that the filter element according to the first or
second aspect may
be used in the manufacture of a filter, for use in a smoking article.
Hence, according to a third aspect of the invention, there is provided a
filter for a
smoking article, the filter comprising a filter element according to the first
or second
aspect.
The filter of the third aspect may comprise a plurality of filter elements
according to the
first or second aspect, in which a tobacco core extends through a plug of
filter material.
For example, the filter may comprise 2, 3, 4, 5 or more filter elements of the
first or
second aspect, in which adjacent filter elements may either be connected to
each other,
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or which elements may be separated from each other by other filter elements
(which
may not be in accordance with the first or second aspect).
Hence, the filter may comprise a plurality of filter elements, at least one of
which is a
filter element according to the first or second aspect of the invention. For
example, it is
envisaged that, in one embodiment, in addition to comprising one or more
filter
elements according to the first or second aspect (ie. containing the tobacco
core), the
filter of the third aspect may also comprise an adsorbent filter element,
which element
comprises an adsorbent material. The adsorbent filter element is provided to
adsorb
and, hence, reduce certain components of the smoke during smoking. The
adsorbent
filter element may comprise a plug of filter material in which the adsorbent
material is
dispersed. The filter material may be cellulose acetate. A preferred adsorbent
material
is activated carbon. The activated carbon may be in the form of granular
activated
carbon, which is preferably distributed substantially throughout the volume of
the plug
of filter material. Preferably, the adsorbent filter element does not include
a tobacco
core.
In another embodiment, in addition to comprising one or more filter elements
according to the first or second aspect (ie. containing the tobacco core), the
filter of the
third aspect may also comprise a filter element, which comprises filter
material (such as,
cellulose acetate), and which does not include a tobacco core or adsorbent
material.
The filter may comprise at least two, and preferably at least three filter
elements,
provided that at least one filter element is in accordance with the first or
second aspect.
Preferably, the filter comprises a filter element according to the first or
second aspect,
an adsorbent filter element comprising adsorbent, and a filter element, which
does not
include adsorbent or a tobacco core. Preferably, multiple filter elements are
arranged
longitudinally of one another with the end face of one filter element abutting
the end
face of an adjacent filter element. It is preferred that the filter elements
have
substantially similar diameters. It should be appreciated that the various
filter elements
may be in any order in the filter, as illustrated in Figures 3 and 4.
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The filter element of the first or second aspect, or the filter of the third
aspect, may be
incorporated into a smoking article.
Hence, according to a fourth aspect of the invention, there is provided a
smoking
article comprising a filter element according to the first or second aspect,
or a filter
according to the third aspect.
The smoking article preferably comprises a section or rod of smokeable
material, such
as tobacco. 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.
The section of smokeable material and the filter may be attached by tipping
paper.
According to a fifth aspect of the invention, there is provided a method of
manufacturing a filter element for a smoking article, the method comprising
providing a
tobacco core through a plug of filter material, wherein the tobacco core
extends
substantially longitudinally through the plug of filter material, and wherein
wrapping
means is wrapped around at least a portion of a longitudinally extending
surface of the
tobacco core.
According to a sixth aspect, there is provided a method of manufacturing a
filter
element for a smoking article, the method comprising providing a tobacco core
through
a plug of filter material, wherein the tobacco core extends substantially
longitudinally
through the plug of filter material, and wherein the tobacco core comprises,
or is
derived from, a longitudinal section of a tobacco rod of a smoking article.
The method of the sixth aspect may comprise a step of arranging a longitudinal
section
of a tobacco rod of a slim-sized smoking article, such that it extends
substantially
longitudinally through the plug of filter material. Preferably, the method of
the sixth
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aspect comprises cutting the slim-sized tobacco rod into a section of suitable
length
prior to being arranged in the plug of filter material.
The methods of the fifth or sixth aspect preferably comprise a step of
introducing the
tobacco core into substantially the centre of the filter material. The methods
may
comprise using guide means to guide the tobacco core as a tow of filter
material is
formed therearound. The guide means may comprise a guide tube through which
the
tobacco core is entrained. As the core exits the guide means, it is preferably
surrounded by filter material.
All of the features described herein (including any accompanying claims,
abstract and
drawings), and/or all of the steps of any method or process so disclosed, may
be
combined with any of the above aspects in any combination, except combinations
where at least some of such features and/or steps are mutually exclusive.
For a better understanding of the invention, and to show how embodiments of
the
same may be carried into effect, reference will now be made, by way of
example, to the
accompanying Figures, in which:-
Figure 1 shows a perspective view of a smoking article, including a rod of
smokeable
material, a filter in accordance with the invention, and tipping paper
attaching the rod
and filter together;
Figure 2 shows a cross-sectional side view of a first embodiment of the filter
according
to the invention;
Figure 3 shows a cross-sectional side view of a second embodiment of the
filter; and
Figure 4 shows a cross-sectional side view of a third embodiment of the
filter.
Referring to Figure 1, there is shown a smoking article 2, in the form of a
cigarette,
which includes a filter 4 in accordance with the invention. Even though the
Figures
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show the smoking article 2 as a cigarette, it should be appreciated that the
smoking
article 2 may take other forms, such as cigars and cigarillos etc, which may
also include
the filter 4 according to the invention.
Referring to Figure 1, the smoking article 2 comprises a generally cylindrical
paper-
wrapped rod 6 of smokeable material, such as tobacco, which is co-axially
attached to
the filter 4 by tipping paper 8, which is glued around one end of the rod 6
and the filter
4.
Referring to Figure 2, there is shown a first embodiment of the filter 4
attached to the
rod of tobacco 6. In this embodiment, the filter 4 is made up of a single,
filter element
12 about 27mm in length, which consists of a continuous plug of filter
material 20 (for
example, cellulose acetate) having a diameter of 9mm. The filter element 12
has first
and second generally circular end faces 22, 24, and a circumferential or
longitudinally
extending side surface 26 substantially perpendicular to the first and second
end faces
22, 24.
As shown in Figure 2, a cylindrical tobacco core 10 having a diameter of 3mm
extends
between the two end faces 22, 24 through the plug of filter material 20. In
order to
retain the tobacco as a core 10, it is wrapped in plugwrap or cigarette paper
11. The
paper 11 is substantially pervious to air, such that smoke can pass
therethrough as a
smoker inhales. The tobacco core 10 is substantially parallel with the
longitudinally
extending surface 26 of the filter element 12, and extends substantially
through the
centre of the plug of filter material 20.
In some embodiments, the tobacco core 10 is derived from a tobacco rod which
would
otherwise be used in the manufacture of a superslim cigarette, examples of
which are
sold under the trade name Vogue (dimensions: 5mm x 99mm) or Kent Nanotek
(dimensions: 5mm x 83mm), which may be obtained from British American Tobacco
Company, and available in Europe and Russia. It is envisaged that the tobacco
core 10
consists of cut tobacco lamina, a cut tobacco blend or cut tobacco stems,
which is
wrapped in plugwrap or cigarette paper 11. Hence, the tobacco rod section of a
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suitable superslim cigarette consisting of a tobacco core wrapped in cigarette
paper is
used to form the tobacco core 10 wrapped in plugwrap 11 of the filter element
12 of
the present invention.
The wrapped tobacco core 10 is approximately 3mm in diameter, which is then
introduced into the centre of the filter material 20. One method of
introducing the
tobacco core 10 in to the plug of filter material 20 in the manufacture of the
filter
element 12 as follows. The method involves entraining the tobacco core 10
through the
lumen of a guide tube having a diameter of about 5mm. Simultaneously, a supply
of
fibrous filter material 20 (e.g. cellulose acetate) is passed through a series
of blooming
rollers so that it is de-crimped. A tow of de-crimped filter material 20 is
then formed
around the core 10 as it exits the guide tube, to thereby form a continuous
rod of filter
material 20 enclosing the wrapped tobacco core 10. The rod may then be cut up
in to
sections of appropriate length to produce the completed filter element 12 as
shown in
Figure 2. The length of the filter element 12 will depend on the type of
filter 4
required. For example, a standard cigarette filter 4 is about 27mm in length.
In the
embodiment shown in Figure 2, the whole 27mm length of the filter 4 consists
of the
filter element 12, such that the core 10 extends all the way along. However,
Figures 3
and 4 illustrate other embodiments, in which the filter 4 comprises a shorter
section of
the filter element 12 containing the core 10 in combination with other
sections, as
described below.
Referring to Figure 3, there is a shown a second embodiment of the filter 4
attached to
the rod of tobacco 6. The filter 4 comprises a plurality of different discrete
filter
elements 12, 14, 16, each of which may have a different material composition.
In this
embodiment, the filter 4 includes three different filter elements 12, 14, 16.
Each filter
element 12, 14, 16 is generally cylindrical in shape having substantially
equivalent
diameters. Each filter element 12, 12, 16 is wrapped by a layer of thin sheet
material in
the form of a wrapper known as plugwrap (not shown), which may be formed of
conventional paper materials. The filter element 16 that is farthest from the
tobacco
rod 6 (and which will be closest to the smoker's mouth when in use) comprises
a
generally cylindrical tow of filter material 20, such as cellulose acetate.
The filter
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material 20 provides a filter through which smoke may pass as a smoker inhales
on the
cigarette. The filter element 12 that is disposed adjacent element 16 contains
a
continuous plug of filter material 20 having the tobacco core 10 extending
substantially
longitudinally therethrough. This filter element 12 is similar to that shown
in Figure 1,
except that it does not extend along the entire length of the filter 4.
The third filter element 14 that is disposed between the filter element 12
containing the
tobacco core 10 and the tobacco rod 6 comprises a plug of filter material 20,
in which
an adsorbent, such as activated carbon 18, has been dispersed. The activated
carbon 18
may be in the form of granular activated carbon 18, which is distributed
evenly
throughout the volume of the plug of cellulose acetate 20 in a "Dalmatian"
style, as is
known in the art, and as shown in Figure 3. Alternatively, the activated
carbon 18 may
be sprinkled onto a sticky exterior surface 26 of the plug of cellulose
acetate 20, or
adhered to the inner surface of the plugwrap surrounding the cellulose
acetate, or may
be adhered to a cotton thread surrounded by the plug of cellulose acetate 20
(not
shown). The activated carbon 18 could also be held in a cavity surrounded by
the plug
of cellulose acetate 20. The activated carbon 18 is provided to improve the
characteristics of the smoke that is inhaled by removing toxic chemicals.
Referring to Figure 4, there is shown a third embodiment of the filter 4
attached to the
tobacco rod 6. In this embodiment, the filter 4 includes the same three filter
elements
12, 14, 16 as in the second embodiment, as described above, except that the
order of
the elements has been changed. As shown in Figure 4, the filter element 16
that is
farthest from the tobacco rod 6 comprises filter material 20, such as
cellulose acetate, as
in the second embodiment. However, in the third embodiment, the filter element
12
that is disposed adjacent element 16 contains a plug of filter material 20, in
which
particles of activated carbon 18 have been dispersed. Finally, the third
filter element 12
disposed between element 14 and the rod of tobacco 6 contains a continuous
plug of
filter material 20 through which the tobacco core 10 extends. Accordingly, the
positions
of filter elements 12, 14 have been swapped in the second and third
embodiments.
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As shown in Figures 3 and 4, the filter elements 12, 14, 16 are arranged
longitudinally
of one another with the end face 22, 24 of each filter element 12, 14, 16
abutting the
next. Although the three filter elements 12, 14, 16 are shown in Figures 3 and
4 as being
substantially equal in length, it will be appreciated that they could have
different lengths.
For example, in Figures 3 and 4, the filter element 12 containing the tobacco
core 10
could be 12mm in length, and the other elements 14, 16 could be 7.5mm each,
such
that the total length of the filter 4 is 27mm. In addition, it will be
appreciated that the
filter 4 may comprise only the two filter elements. For example, the filter 4
may
comprise the filter element 12 containing the tobacco core 10 (about 15mm
long) and
9o the filter element 16 containing only filter material 20 (about 12mm long),
in either
order. Alternatively, the filter 4 may comprise the filter element 12
containing the
tobacco core 10 and the filter element 14 containing activated carbon 18, in
either
order.
Also, the filter 4 may comprise more than three filter elements 12, 14, 16.
For example,
the filter 4 may comprise first and second filter elements 16 composed of
cellulose
acetate, a third filter element 14 comprising cellulose acetate and activated
carbon 18,
and a fourth filter element 12 comprising the longitudinal tobacco core 10, as
described
above. It will be appreciated that the various filter elements 12, 14, 16 may
be arranged
in the filter 4 in a variety of alternative orders. However, in each
embodiment, at least
one filter element 12 containing the tobacco core 10 is included in the filter
4.
Referring to Figure 1 once again, the filter 4 is located at a mouth-end of
the smoking
article 2 such that a gaseous flow, comprising smoke drawn from the rod 6 of
smokeable material, moves through the filter 4 before entering the mouth of a
smoker.
The tobacco core 10 is located in one or more filter elements 12, and extends
longitudinally between the end faces 22, 24 of a plug of filter material 20,
as described
in relation to Figure 2. In this way, the tobacco core 10 is disposed in close
proximity
with the path of the gaseous flow as it moves through the filter 4, and is
therefore able
3o to affect various characteristics of the gaseous flow before the flow
reaches the
smoker's mouth.
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The tobacco core 10 may, for example, affect the overall properties of the
gaseous flow
such that the taste and flavour of the gaseous flow are improved. One
application of
the tobacco core 10 is to replace a degree of the taste and flavour
characteristics of the
gaseous flow which may be lost as the gaseous flow moves through the filter
material
20, or the activated carbon 18, which is known to affect the taste and flavour
of
tobacco smoke. The inventors have surprisingly found that the arrangement of
the
tobacco core 10 extending longitudinally through the plug of filter material
20 improves
the flavour of the smoke without compromising the flow characteristics of the
smoke.
The invention also includes further modifications and variations falling
within the scope
to of the claims.
