U.S. patent application number 15/333721 was filed with the patent office on 2017-02-09 for smoking article filters.
This patent application is currently assigned to British American Tobacco (Investments) Limited. The applicant listed for this patent is British American Tobacco (Investments) Limited. Invention is credited to Andrew Davis, David Lewis, John Major, John Richardson, John Sampson.
Application Number | 20170035103 15/333721 |
Document ID | / |
Family ID | 46330760 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170035103 |
Kind Code |
A1 |
Lewis; David ; et
al. |
February 9, 2017 |
SMOKING ARTICLE FILTERS
Abstract
The present invention relates to improvements in filters for use
in smoking articles such as cigarettes, cigars and cigarillos. The
improvements, particularly but not exclusively, relate to filter
capabilities and to the manufacture of such filters. In one
example, a filter for a smoking article comprises a first fibrous
filter material having an average fibre denier in the range 7 to 9
and a second fibrous filter material having an average fibre denier
of below 7. The application also describes a filter for a smoking
article comprising various other filter arrangements including
absorbent and/or adsorbent materials.
Inventors: |
Lewis; David; (London,
GB) ; Davis; Andrew; (London, GB) ;
Richardson; John; (London, GB) ; Major; John;
(London, GB) ; Sampson; John; (London,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
British American Tobacco (Investments) Limited |
London |
|
GB |
|
|
Assignee: |
British American Tobacco
(Investments) Limited
London
GB
|
Family ID: |
46330760 |
Appl. No.: |
15/333721 |
Filed: |
October 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14398648 |
Nov 3, 2014 |
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PCT/GB2013/051142 |
May 2, 2013 |
|
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15333721 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/061 20130101;
A24D 3/10 20130101; A24D 3/14 20130101; A24D 3/04 20130101; A24D
3/08 20130101; A24D 3/062 20130101; A24D 3/048 20130101; A24D 3/063
20130101; A24D 3/12 20130101; A24D 3/16 20130101 |
International
Class: |
A24D 3/06 20060101
A24D003/06; A24D 3/14 20060101 A24D003/14; A24D 3/10 20060101
A24D003/10; A24D 3/08 20060101 A24D003/08; A24D 3/04 20060101
A24D003/04; A24D 3/16 20060101 A24D003/16 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2012 |
GB |
1207779.8 |
Claims
1-15. (canceled)
16. A smoking article filter, comprising randomly oriented short
length fibers of a first material and randomly oriented short
length fibers of a second material, wherein the second material
comprises at least one material including at least one of polyvinyl
alcohol (PVOH), polylactic acid (PLA),
poly(.epsilon.-caprolactone)(PCL), poly(1-4 butanediol
succinate)(PBS), poly(butylene adipate-co-terephthalate)(PBAT),
starch based materials, paper, aliphatic polyester materials and
polysaccharide polymers, nanofibers, carbon nanofibers and/or
nanofibers supporting a catalytic agent.
17. The filter according to claim 16, wherein the first material
comprises cellulose acetate.
18. The filter according to claim 16, wherein the second material
comprises a non-crimped material.
19. The filter according to claim 16, wherein the catalytic agent
comprises zinc oxide (ZnO) or gold (Au).
20. The filter according to claim 16, wherein the nanofibers have a
length between 1 mm and 15 mm.
21. The filter according to claim 16, wherein the filter has a
non-cylindrical shape.
22. The filter according to claim 16, wherein the filter has a
cylindrical shape and a circumference less than 16 mm or greater
than 25 mm.
23. The filter according to claim 16, further comprising a flavor
release component.
24. The filter according to claim 17, wherein the second material
comprises a non-crimped material.
25. A smoking article comprising a filter according to claim 16.
Description
TECHNICAL FIELD
[0001] The present invention relates to improvements in filters for
use in smoking articles. Particularly but not exclusively the
improvements relate to filter capabilities and to the manufacture
of such filters.
BACKGROUND
[0002] A known filtering material used in cigarette filters is a
continuous tow of filamentary cellulose acetate plasticised with
triacetin. The cellulose acetate is gathered together to form a rod
which is cut to form individual filter segments. The filter for a
smoking article may be made of one segment of filter rod, or may be
made from multiple segments, with or without a cavity or spaces
between them.
SUMMARY
[0003] According to embodiments of the invention, there is provided
a filter for a smoking article comprising a first fibrous filter
material having an average fibre denier in the range 7 to 9 and a
second fibrous filter material having an average fibre denier of
below 7, wherein the second fibrous filter material is dispersed
within the first fibrous filter material, and wherein the first and
second fibrous filter materials comprise discrete short length
fibres which are randomly oriented in the filter.
[0004] The randomly oriented short length fibres can be held
together in the filter without the use of a plasticiser.
[0005] The first and/or second fibrous filter materials can
comprise fibres having an average length of from about 5 mm to 20
mm when extended.
[0006] The second fibrous filter material can have an average fibre
denier in the range from 1 to 6.
[0007] The second fibrous filter material can comprise a plurality
of nano fibres.
[0008] The nanofibres can carry an additive for the selective
reduction of at least one constituent of smoke drawn through the
filer in use.
[0009] According to embodiments of the invention, there is further
provided a filter for a smoking article comprising a sheet material
dispersed within randomly oriented short length fibres.
[0010] The sheet material can comprise shredded sheet material
selected from at least one of polyvinyl alcohol (PVOH), polylactic
acid (PLA), poly(.epsilon.-caprolactone)(PCL), poly(1-4 butanediol
succinate) (PBS), poly(butylene adipate-co-terephthalate)(PBAT),
starch based materials, paper, aliphatic polyester materials and
polysaccharide polymers.
[0011] According to embodiments of the invention, there is further
provided a filter for a smoking article comprising randomly
oriented short length fibres formed from a first material and
randomly oriented short length fibres formed from a second
material.
[0012] The first material can comprise cellulose acetate.
[0013] The second material can comprise a non-crimped material.
[0014] The second material can comprise at least one material
selected from polyvinyl alcohol (PVOH), polylactic acid (PLA),
poly(.epsilon.-caprolactone)(PCL), poly(1-4 butanediol
succinate)(PBS), poly(butylene adipate-co-terephthalate)(PBAT),
starch based materials, paper, aliphatic polyester materials and
polysaccharide polymers.
[0015] The filter can be formed into a shape other than a cylinder
or into a cylinder having a circumference smaller than 16 mm or a
circumference greater than 25 mm.
[0016] The filter can further comprise a flavour release
component.
[0017] According to embodiments of the invention, there is further
provided a smoking article comprising a filter as set out
above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Embodiments of the invention will now be described, by way
of example only, with reference to the accompanying drawings, in
which:
[0019] FIG. 1 is a schematic illustration of a smoking article
having a filter with at least one segment having from 12 mg of
adsorbent material per millimetre of length and 4 mg of absorbent
material per millimetre of length, for a regular format filter;
[0020] FIG. 2 is a schematic illustration of a filter making
apparatus for use in manufacturing filters;
[0021] FIG. 3 is a graph illustrating the carbon weight and tow
weight in filters based on desired ranges for filter pressure drop
and hardness;
[0022] FIG. 4 provides three graphs respectively illustrating the
influence of carbon weight, tow weight and machinery operating
speed on pressure drop for filters;
[0023] FIG. 5 provides three graphs respectively illustrating the
influence of carbon weight, tow weight and machinery operating
speed on hardness for filters;
[0024] FIG. 6 is a schematic illustration of a smoking article
having a filter with a first fibrous filter material having an
average fibre denier in the range 7 to 9 and a second fibrous
filter material, dispersed within the first fibrous filter
material, having an average fibre denier of below 7;
[0025] FIG. 7 is a schematic illustration of a smoking article
having a filter with at least one segment including a nanofibre
carrying an additive for enabling or enhancing the reduction of at
least one component of main stream smoke;
[0026] FIG. 8 is a schematic illustration of a smoking article
having a filter with at least one segment comprising randomly
oriented discrete short length fibres having a thread extending
therethrough;
[0027] FIG. 9 is a schematic illustration of a smoking article
having a filter with at least one segment comprising randomly
oriented discrete short length fibres having a capsule disposed
therein;
[0028] FIG. 10 is a schematic illustration of a smoking article
having a filter with at least one segment comprising randomly
oriented discrete short length fibres having microcapsules disposed
therein;
[0029] FIG. 11 is a schematic illustration of a smoking article
having a filter with at least one segment comprising randomly
oriented discrete short length fibres having shredded sheet
material disposed therein;
[0030] FIG. 12 is a schematic illustration of a smoking article
having a filter with at least one segment comprising randomly
oriented discrete short length fibres having degradable fibres
disposed therein;
[0031] FIG. 13a is a schematic illustration of a filter rod
comprising regions of higher average density and regions of lower
average density;
[0032] FIG. 13b is a schematic illustration of a section of a
filter forming band for producing filter segments having regions of
higher average density and regions of lower average density;
[0033] FIG. 14 is a schematic illustration of a smoking article
having a filter comprising an elliptical cross-section; and
[0034] FIG. 15 is a schematic illustration of a smoking article
having a filter comprising a square cross-section.
DETAILED DESCRIPTION
[0035] 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. Such smoking articles may be provided with a filter for
the gaseous flow drawn by the smoker.
[0036] Smoking articles such as cigarettes and their formats are
often named according to the cigarette length: "regular" (typically
in the range 68-75 mm, e.g. from about 68 mm to about 72 mm),
"short" or "mini" (68 mm or less), "king-size" (typically in the
range 75-91 mm, e.g. from about 79 mm to about 88 mm), "long" or
"super-king" (typically in the range 91-105 mm, e.g. from about 94
mm to about 101 mm) and "ultra-long" (typically in the range from
about 110 mm to about 121 mm).
[0037] They are also named according to the cigarette
circumference: "regular" (about 23-25 mm), "wide" (greater than 25
mm), "slim" (about 22-23 mm), "demi-slim" (about 19-22 mm),
"super-slim" (about 16-19 mm), and "micro-slim" (less than about 16
mm). Accordingly, a cigarette in a king-size, super-slim format
will, for example, have a length of about 83 mm and a circumference
of about 17 mm. Cigarettes in the regular, king-size format are
preferred by many customers, namely with a circumference of from 23
to 25 mm and an overall length of from 75 to 91 mm.
[0038] Each format may be produced with filters of different
lengths, smaller filters being generally used in formats of smaller
lengths and circumferences. Typically the filter length will be
from 15 mm, associated with short, regular formats, to 30 mm,
associated with ultra-long super-slim formats. The tipping paper
will have a greater length than the filter, for example from 3 to
10 mm longer.
[0039] FIG. 1 is a schematic illustration of a smoking article 1
having a filter. The smoking article 1 is in the regular, king size
format, namely having a length in the range 75-91 mm and a
circumference in the range 23 to 25 mm. The smoking article 1
includes a tobacco rod 2 wrapped in a wrapping material 3, in this
case cigarette paper, connected longitudinally to a filter 4 by
tipping material 5 overlaying the filter 4 and partially overlaying
the wrapping material 3. The filter 4 comprises a first segment 6
at the mouth-end of the filter 4 comprising crimped cellulose
acetate tow 7 wrapped in a first plug wrap 8, and a second segment
9 at the tobacco rod end of the filter 4 comprising absorbent
material 10 having an adsorbent material 11 dispersed therein and
wrapped in a second plug wrap 12.
[0040] The first segment 6 is a cellulose acetate segment formed
using continuous cellulose acetate fibres and a plasticiser.
[0041] The absorbent material 10 of the second segment 9 comprises
randomly oriented discrete short length cellulose acetate fibres
and the adsorbent material 11 comprises activated carbon particles.
The randomly oriented discrete short length cellulose acetate
fibres of the second segment 9 are non-plasticised fibres. The
randomly oriented discrete short length cellulose acetate fibres of
the second segment 9 comprise 8 denier, 10 mm fibre lengths.
However, other denier fibres or fibre lengths can be used. For
instance, fibre deniers in the range 5 to 9 or 7 to 9 can be used.
In terms of fibre length, when used herein, the term `short length`
means fibre lengths of fibres in the form used in a filter segment
(i.e. crimped or uncrimped as appropriate) which are shorter than
the length of the filter segment. Average fibre lengths (when the
fibres are extended) in the range from 5 mm to 25 mm, or from 6 mm
to 20 mm, 7 mm to 20 mm or 7 mm to 15 mm can be used. The activated
carbon particles are in the present example coconut carbon provided
in a 30/70 mesh size, although other carbons and/or sizes can be
used. For instance, particles with diameters in the range of
approximately 0.1 to 1.0 mm, or approximately 0.2 to 0.9 mm, 0.2 to
0.8 mm, 0.2 to 0.7 mm, 0.2 to 0.6 mm, 0.3 to 0.9 mm, 0.3 to 0.8 mm,
0.3 to 0.7 mm or 0.3 to 0.6 mm can be used.
[0042] The second segment 9 has 12 mg of adsorbent material per
millimetre of length and 4 mg of absorbent material per millimetre
of length. However, in alternative examples, the amount of
adsorbent can be anywhere in the range from 6 mg to 16 mg per mm
length on average, or from 7 mg to 16 mg, 8 mg to 16 mg, 9 mg to 16
mg, 10 mg to 16 mg, 11 mg to 16 mg, 12 mg to 16 mg, or 13 mg to 16
mg per mm length and the amount of absorbent can be from 1.5 mg to
8 mg per mm length on average, or from 1.5 mg to 7 mg, 1.5 mg to 6
mg, 1.5 mg to 5 mg, or 1.5 mg to 4 mg, all of these ranges being
for a regular format filter, i.e. having a circumference of about
23 to 25 mm. It has been found that these parameters enable the
filter to exhibit desirable pressure drop and hardness levels for
consumer acceptable smoking articles, while increasing the level of
adsorbent or other granular additive in the filter over known
filters.
[0043] The filter material of the second segment 9, for instance,
exhibits desirable pressure drop in the range 500 to 700 mmWg for
an experimental sample having a 144 mm filter length (3.47 to 4.86
mmWg/mm) and desirable hardness of between 85% to 95% according to
the Filtrona filter hardness measure (defined as the compressed
diameter of the filter rod as a percentage of the initial rod
diameter, the compression of the rod being caused by a known weight
applied through a circular foot for a specific period of time).
Alternative weights of adsorbent material and absorbent material
per mm of filter length would be used for filters in formats other
than regular, for instance having slimmer or wider average
diameters, as would be appreciated by those skilled in the art.
[0044] An increase in the pressure drop and/or hardness percentage
resulting from an increase in the amount of adsorbent per mm in a
filter can be offset by a decrease in the amount of absorbent per
mm. Also, an increase in the pressure drop and/or hardness
percentage resulting from an increase in the amount of absorbent
per mm in a filter can be offset by a decrease in the amount of
adsorbent per mm. The inventors have, in particular, found that the
amount of adsorbent material in mg, C.sub.w, per mm in length for a
regular format smoking article, and the amount of absorbent
material in mg, T.sub.w, per mm in length for a regular format
smoking article, can be determined in accordance with the
range:
10.ltoreq.(C.sub.w+T.sub.w).ltoreq.20,
these values enabling the filter to exhibit appropriate levels of
filter pressure drop and hardness, such as those discussed
above.
[0045] Particular benefits can be achieved if the amount of
adsorbent material and the amount of absorbent material in mg per
mm of length for a regular circumference smoking article fall
within the range:
11.ltoreq.(C.sub.w+T.sub.w).ltoreq.18,
or more particularly within the range:
12.ltoreq.(C.sub.w+T.sub.w).ltoreq.17.
[0046] Advantages can also be achieved using adsorbent and
absorbent weights, in mg per mm of length for a regular
circumference smoking article, in other ranges, including
10.ltoreq.(C.sub.w+T.sub.w).ltoreq.19,
10.ltoreq.(C.sub.w+T.sub.w).ltoreq.18,
10.ltoreq.(C.sub.w+T.sub.w).ltoreq.17,
11.ltoreq.(C.sub.w+T.sub.w).ltoreq.20,
12.ltoreq.(C.sub.w+T.sub.w).ltoreq.20,
13.ltoreq.(C.sub.w+T.sub.w).ltoreq.20 and
14.ltoreq.(C.sub.w+T.sub.w).ltoreq.20.
[0047] In addition to selected adsorbent and absorbent weights per
mm falling within the above ranges, at least one of the adsorbent
and absorbent weight C.sub.w, T.sub.w can be greater than a minimum
level. For instance, the absorbent level can be equal to or greater
than about 1.5 mg per mm in some embodiments of the invention
and/or the adsorbent can be equal to or greater than 6 mg per mm,
both minimum levels being for a regular circumference filter, of
about 23 mm to 25 mm.
[0048] The above ranges can also be applied for use with granular
additives other than adsorbents, such as certain flavourants (where
local regulations permit).
[0049] The second filter segment 9 can be manufactured using a
filter manufacturing apparatus such as the Turmalin apparatus
available from Hauni Maschinenbau AG in Germany.
[0050] In cases in which the absorbent weight per mm is less than
3.5 mg per mm and/or the adsorbent weight per mm is less than 9 mg
per mm (both for a regular circumference smoking article), and/or
the combined adsorbent and absorbent weight per mm is at the lower
end of the above ranges, for instance 12 mg per mm or lower, the
inventors have determined that a reduction in hardness caused by
these low weights can be offset by using, for instance, a stiffer
plug wrap and/or stiffer tipping material surrounding the filter.
For instance, the plug wrap and/or tipping could have a basis
weight of greater than 30 g/m.sup.2, greater than 40 g/m.sup.2,
greater than 50 g/m.sup.2, greater than 60 g/m.sup.2, greater than
70 g/m.sup.2 or greater than 80 g/m.sup.2. Alternatively, multiple
layers of plug wrap and/or tipping material can be used.
[0051] Known Dalmatian filters, i.e. those comprising carbon
particles dispersed in continuous cellulose acetate tow cut
according to the required segment length, in the regular format,
generally have an upper carbon loading limit of 5 mg/mm in order to
keep the pressure drop at levels desirable for consumers. Higher
loading could result in the pressure drop being too high. If it was
desired to have a higher loading then, in the past, it was usually
necessary to use a cavity triple filter, having mouth-end and
tobacco end cellulose acetate tow sections with a carbon filled
cavity between them. Such cavity filters result in the removal of a
quantity of cellulose acetate for a given filter length and so this
can have a negative effect, for instance on particular aspects of
tar filtration and phenol selectivity. As such, there are clear
advantages to being able to increase the loading of additives
without causing too great a pressure drop and without the removal
of filtration material.
[0052] The present inventors accordingly have recognised that by
using randomly oriented discrete short length cellulose acetate
fibres for forming the filter, manufactured using a filter
manufacturing apparatus such as the Turmalin apparatus available
from Hauni Maschinenbau AG in Germany, and by selecting the amount
of adsorbent to be in the range from 6 mg to 16 mg per mm on
average, and the amount of absorbent to be in the range from 1.5 mg
to 8 mg per mm on average (or the other ranges and limits set out
above), for a regular circumference cigarette, improved filters can
be provided whilst maintaining acceptable pressure drop and filter
hardness parameters.
[0053] FIG. 2 is a schematic illustration of a filter making
apparatus, such as the Turmalin apparatus available from Hauni
Maschinenbau AG in Germany, for use in manufacturing filters.
[0054] Referring to FIG. 2, a source 21 of cellulose acetate or
other filter material is supplied to the filter making apparatus
20, which comprises a plurality of modules 22-26. A feeder module
22 receives the supply of filter material, for instance crimped
continuous fibres such as crimped cellulose acetate tow, from which
it is fed into a cutter and randomiser 23. The cutter and
randomiser 23 cuts the filter material into short staple lengths,
for instance 10 mm lengths. Other fibre lengths can be used, as
described above in relation to the smoking article 1 described with
reference to FIG. 1. A filter bander 24 includes a vacuum band onto
which the cut filter material is provided. This is fed into a rod
former 25, for forming the band of cut filter material into a rod
which is wrapped with a plug wrap. Finally, a segment cutter 26 is
used to cut the rod into filter segments of a desired length.
[0055] The filter bander 24 comprises a carding unit which
distributes the cut fibres evenly onto the vacuum band, and a
plurality of hoppers, two in the present example, for applying
additives, for instance in the form of granules or additional
fibres. There is also an add-back system which can be used if
required to feed a third additive into the band of cut filter
material. The add-back system alternatively may be used to feed any
loose cut filter material back into the cutter and randomiser 23 to
reduce wastage. The filter bander 24 comprises metering rollers
which are adjustable to permit control over the additive loading
and to ensure uniformity of the band of cut filter material as it
is formed. The filter bander 24 also comprises a jet inserter for
enabling liquids such as flavours (where local regulations permit
the use of flavours) to be injected directly into the filter
rod.
[0056] In use, the Turmalin apparatus operates as follows: the
feeder module 22 feeds filter material such as crimped cellulose
acetate tow into the cutter and randomiser 23. The cutter and
randomiser 23 cuts the tow fibres into short staple lengths of 10
mm in the present example. The cut filter material is blown to the
carding unit of the filter bander 24 from which it is sucked onto
the vacuum band, where it is formed into a band of randomly
orientated filter material. The bander 24 operates in such a way
that the resultant hand of filter material is mechanically bonded.
Additives are fed into the air stream carrying the filter fibres,
and the rod former 25 forms the band into a continuous filter rod,
which is bound by a filter plug wrap. The segment cutter 26 cuts
the continuous filter rod, comprising randomly orientated fibres,
into segments of a desired length.
[0057] Appreciated advantages of the Turmalin apparatus include:
the inclusion of additives, for example carbon, at higher loadings;
retention of the activity of carbon additives because without
plasticisers such as triacetin there is no poisoning of the
charcoal; and a longer product life. The filter designs and
manufacturing developments created by the inventors which are
described below lead to further advantages and improvements.
[0058] It is possible to generate a series of filter capability
curves for differing tow weights, additive loadings and machinery
operating speeds, such that filter designs can be optimised to
desired filter characteristics, such as pressure drop and hardness
level. This thereby increases the range of different filters which
can be manufactured, and which may have purposely different
capabilities depending on the requirements for a particular
product.
[0059] FIG. 3 is a graph illustrating the additive weight (in the
present case carbon weight) and tow weight in filters based on
preferred ranges for their pressure drop and hardness. In
particular, the tow weight and carbon weight required for a filter
pressure drop of from 500 to 700 mmWg for a 144 mm filter length
(3.47 to 4.86 mmWg/mm) and for a filter hardness level from 85% to
95%, according to the Filtrona filter hardness measure, are
indicated in the graph, which represents data from filters produced
using the Hauni Turmalin apparatus. The device can be operated at
speed settings from below 50 m/min up to over 200 m/min. The carbon
used was 30/70 mesh coconut carbon, dispersed within 8 denier
non-plasticised, crimped randomly oriented cellulose acetate tow
fibres cut to 10 mm lengths. For these particular filter
parameters, the resulting contour plot of FIG. 3 illustrates the
range of tow and carbon weights per mm for a regular circumference
smoking article which can be obtained while achieving desired
characteristics such as pressure drop and hardness within
predefined ranges.
[0060] In relation to the pressure drop of the filter, FIG. 4 is a
graph illustrating the influence of carbon weight, tow weight and
machinery operating speed on pressure drop for filters. Again, the
carbon used was 30/70 mesh coconut carbon, dispersed within 8
denier non-plasticised, crimped randomly oriented cellulose acetate
tow fibres cut to 10 mm lengths. While the operating speed of the
machinery has relatively little effect on the pressure drop and the
tow weight has a generally linear relationship, surprisingly the
inventors have realised that an increased carbon weight beyond 10
mg/mm can be shown in some cases to reduce filter pressure drop for
a given tow density, based on filters manufactured using the
Turmalin apparatus. This is a significant result, indicating that
the level of carbon can be increased beyond 10 mg/mm without having
an adverse influence on filter pressure drop.
[0061] In relation to the hardness of the filter, FIG. 5 provides
three graphs illustrating the influence of carbon weight, tow
weight and machinery operating speed on hardness for filters.
Again, the carbon used was 30/70 mesh coconut carbon, dispersed
within 8 denier non-plasticised, crimped randomly oriented
cellulose acetate tow fibres cut to 10 mm lengths. In a similar way
to pressure drop, while the operating speed of the machinery has
relatively little effect on the hardness and the tow weight has a
generally linear relationship, surprisingly the inventors have
realised that an increased carbon weight beyond 10 mg/mm in fact
reduces filter hardness for a given tow density for filters
manufactured using the Turmalin apparatus. This is a significant
result, indicating that the level of carbon can be increased beyond
10 mg/mm without having an adverse influence on filter
hardness.
[0062] Although the additive in the above embodiments has been
described as particles of adsorbent, in particular activated
carbon, other adsorbents, or other additives, can also be used. For
instance, the adsorbent could be an ion exchange resin, such as
CR20, or other materials such as zeolite, silica gel, meerschaum,
aluminium oxide (activated or not), carbonaceous resin, magnesium
silicate, including Sepiolite
(Mg.sub.4Si.sub.6O.sub.15(OH).sub.2.6H.sub.2O) or combinations
thereof with or without activated carbon. Also, other additives
which modify the smoke drawn through the filter, such as flavourant
(where local regulations permit the use of flavourants) for example
menthol crystals, or humectant particles, can be used.
[0063] It has previously been known to manufacture filters
comprising randomly oriented discrete tow fibres, for example as
described in WO 2009/093051. However, similar to conventional
acetate tow filters, the manufacturing technique described in WO
2009/093051 can also require the use of a plasticising agent, e.g.
triacetin, to cause bonding within the randomly orientated fibres
to give a firm structure. An advantage of the Turmalin apparatus is
that it does not require the use of a plasticising agent. The
Turmalin apparatus causes a mechanical bonding within the fibres
making the need for plasticiser obsolete. Any undesirable effects
caused by using products such as triacetin are therefore
eliminated.
[0064] In addition to the above advantage, the present inventors
have appreciated that the Turmalin apparatus, or similar, enables
various filter designs to be made which offer additional
improvements and advantages. Such improvements and advantages are
described in detail below.
[0065] The inventors have appreciated that the capabilities of the
filters manufactured using a process such as that of the Turmalin
apparatus can be improved by using materials with smaller particle
sizes than traditionally used. Smaller particles can enhance that
filtration performance because they have larger surface area.
[0066] FIG. 6 is a schematic illustration of a smoking article 31.
The smoking article 31 comprises a tobacco rod 32 wrapped in a
wrapping material 33, in this case cigarette paper, connected
longitudinally to a filter 34 by tipping material 35 overlaying the
filter 34 and partially overlaying the wrapping material 33. The
filter 34 comprises a first segment 36 at the mouth-end of the
filter 34 comprising crimped cellulose acetate tow 37 wrapped in a
first plug wrap 38, and a second segment 39 at the tobacco rod end
of the filter 34 comprising a first absorbent material 40 and a
second absorbent material 41 wrapped in a second plug wrap 42.
[0067] The first segment 36 is a cellulose acetate segment formed
using continuous cellulose acetate fibres and a plasticiser.
[0068] The first absorbent material 40 comprises a fibrous filter
material having an average fibre denier in the range 7 to 9 and the
second absorbent material 41, dispersed within the first absorbent
material 40, comprises a fibrous filter material having an average
fibre denier of below 7, for instance a denier of about from 1 to
6, 2 to 6, 3 to 6, or about 6, 5, 4 3, 2 or 1. The first and second
fibrous filter materials 40, 41 comprise short length fibres which
are randomly oriented in the filter.
[0069] The second filter segment 39 can be manufactured using the
Turmalin apparatus, for instance by supplying a continuous tow of
the first absorbent material 40 to the feeder 22 and by adding
fibres of the second absorbent material via one of the additive
hoppers in the filter bander 24. Alternatively, supplies of the
first and second filter materials 40, 41 can each be provided to
the feeder 21 of the Turmalin apparatus, such that they are cut and
randomised together and processed in a similar way to a single
filter material.
[0070] The fibres of the first and second materials 40, 41 comprise
discrete short length cellulose acetate fibres (as described
herein) in the present example, although alternative fibres can
also be used. For instance, the fibres of the first and/or second
material can comprise cellulose acetate, polyvinyl alcohol (PVOH),
polylactic acid (PLA), poly(.epsilon.-caprolactone)(PCL), poly(1-4
butanediol succinate) (PBS), poly(butylene
adipate-co-terephthalate)(PBAT), starch based materials, paper,
aliphatic polyester materials and polysaccharide polymers or
combinations therefore.
[0071] A further advantage is achievable through the use of
nanofibre materials as a base for catalytic substances to enhance
filter performance. Nanofibres have a sufficiently high surface
area to volume ratio to have the potential for catalytic activity.
Such nanofibres may be added to a filter using the apparatus of
FIG. 2, for instance at the time of additive loading through the
one or more hoppers in the filter bander 24 such that the
nanofibres are metered into the airstream within the filter bander
24.
[0072] FIG. 7 is a schematic illustration of a smoking article 51
having a filter including a nanofibre carrying an additive for
enhancing or enabling the reduction of at least one component of
main stream smoke drawn through the smoking article 51 when in
use.
[0073] Referring to FIG. 7, the smoking article 51 comprises a
tobacco rod 52 wrapped in a wrapping material 53, in this case
cigarette paper, connected longitudinally to a filter 54 by tipping
material 55 overlaying the filter 54 and partially overlaying the
wrapping material 53. The filter 54 comprises a first segment 56 at
the mouth-end of the filter 54 comprising crimped cellulose acetate
tow 57 wrapped in a first plug wrap 58, and a second segment 59 at
the tobacco rod end of the filter 54 comprising nanofibres 60
wrapped in a second plug wrap 61. The first segment 56 is a
cellulose acetate segment formed using continuous cellulose acetate
fibres and a plasticiser. In the present example the nanofibres 60
are short length randomly oriented fibres mixed with cellulose
acetate short length randomly oriented fibres. The nanofibres
comprise carbon nanofibres 60a supporting zinc oxide (ZnO)
particles acting as a catalytic agent 60b, for instance enhancing
the reduction of HCN in cigarette smoke. In alternative
embodiments, other nanofibre materials and/or other catalytic
agents can be used, alone or in combination (including in
combination with carbon and/or ZnO), such as Gold (Au), for
instance for Carbon Monoxide (CO) reduction from cigarette smoke.
The nanofibres 60 can be added as an additive to randomly
orientated staple length cellulose acetate fibres using the filter
making apparatus 20 of FIG. 2.
[0074] The nanofibres can be of any suitable length for inclusion
in a filter segment, for instance between 1 mm and 15 mm, or from 5
mm to 12 mm. The diameters of the nanofibres used can be from 25 nm
to 900 nm, or from 50 nm to 500 nm, or from 100 nm to 300 nm.
[0075] In further embodiments of the invention, where local
regulations permit, flavour may be provided to filters produced
using the Turmalin apparatus.
[0076] The addition of flavour to a filter can be achieved using a
thread as a carrier. An example of suitable apparatus for inserting
threads into filter material is provided in patent publication no.
WO2010/108739 and corresponding U.S. patent application publication
of U.S. application Ser. No. 13/259,634, the contents of which are
incorporated by reference herein. A Thread insertion device, such
as that described in WO2010/108739, can be installed in a central
portion of the filter vacuum band with a thread inserting needle
carrying the thread into the axial region of the filter rod as it
is formed. Embodiments described herein involving the insertion of
threads into filters are particularly advantageous in slim and
super slim formats, i.e. below 22 mm diameters, and in particular
below 21 mm, 20 mm, 18 mm, 16 mm, 15 mm and 14 mm.
[0077] FIG. 8 is a schematic illustration of a smoking article
having a filter comprising randomly oriented discrete short length
fibres having a thread extending therethrough.
[0078] Referring to FIG. 8, the smoking article 151 comprises a
tobacco rod 152 wrapped in a wrapping material 153, in this case
cigarette paper, connected longitudinally to a filter 154 by
tipping material 155 overlaying the filter 154 and partially
overlaying the wrapping material 153. The filter 154 comprises a
first segment 156 at the mouth-end of the filter 154 comprising
crimped cellulose acetate tow 157 wrapped in a first plug wrap 158,
and a second segment 159 at the tobacco rod end of the filter 154
comprising absorbent material 160. A thread 161 extends axially
through the second segment 159. The second segment 159 is wrapped
in a second plug wrap 162. In the present example the absorbent
material 160 comprises randomly oriented discrete short length
cellulose acetate fibres.
[0079] The inventors have also appreciated that the Turmalin
apparatus, or similar, may be arranged to permit the inclusion into
randomly oriented discrete short length fibre filters of capsules,
microcapsules or other encapsulated material, while ensuring
uniform distribution of the capsule contents, such as flavour
(where local regulations permit) or diluents.
[0080] In a similar manner as described in relation to carbon
loading, it is possible to add such materials at higher levels in
order to deliver more flavour. Capsules, whether larger capsules
such as those with diameters between 3 mm and 8 mm, microcapsules
or other encapsulated materials, can be pushed into filter tow in
an apparatus such as the Turmalin apparatus by directing the
capsules through a tube into the filter tow at the downstream end
of the filter bander. The capsules can, for instance, be blown into
the filter material using high pressure gas, at a frequency
corresponding to the speed of the filter bander, such that capsules
are located in the resulting filter rod at appropriate intervals,
and filter segments cut from the filter rod contain the desired
number of capsules. Alternatively, microcapsules could be metered
onto the filter band in a similar way to additives, using one of
the additive hoppers described above. Embodiments described herein
involving the insertion of encapsulated flavourants into filters
are particularly advantageous in slim and super slim formats, i.e.
below 22 mm diameters, and in particular below 21 mm, 20 mm, 18 mm,
16 mm, 15 mm and 14 mm.
[0081] FIG. 9 is a schematic illustration of a smoking article 171
having a filter comprising randomly oriented discrete short length
fibres having a capsule disposed therein. Referring to FIG. 9, the
smoking article 171 comprises a tobacco rod 172 wrapped in a
wrapping material 173, in this case cigarette paper, connected
longitudinally to a filter 174 by tipping material 175 overlaying
the filter 174 and partially overlaying the wrapping material 173.
The filter 174 comprises a first segment 176 at the mouth-end of
the filter 174 comprising crimped cellulose acetate tow 177 wrapped
in a first plug wrap 178, and a second segment 179 at the tobacco
rod end of the filter 174 comprising absorbent material 180. An
encapsulated flavourant 181, in the present case in the form of a
capsule, is disposed within second segment 179. The second segment
179 is wrapped in a second plug wrap 182. In the present example
the absorbent material 180 comprises randomly oriented discrete
short length cellulose acetate fibres.
[0082] FIG. 10 is a schematic illustration of a smoking article
having a filter comprising randomly oriented discrete short length
fibres having microcapsules disposed therein.
[0083] Referring to FIG. 10, the smoking article 191 comprises a
tobacco rod 192 wrapped in a wrapping material 193, in this case
cigarette paper, connected longitudinally to a filter 194 by
tipping material 195 overlaying the filter 194 and partially
overlaying the wrapping material 193. The filter 194 comprises a
first segment 196 at the mouth-end of the filter 194 comprising
crimped cellulose acetate tow 197 wrapped in a first plug wrap 198,
and a second segment 199 at the tobacco rod end of the filter 194
comprising absorbent material 200. Encapsulated flavourant 201, in
the present case in the form of a plurality of microcapsules, is
disposed within second segment 199. The second segment 199 is
wrapped in a second plug wrap 202. In the present example the
absorbent material 200 comprises randomly oriented discrete short
length cellulose acetate fibres.
[0084] In addition to encapsulated flavourants, other forms of
flavour additive (where local regulations permit the use of such
additives) can be added to a filter comprising randomly oriented
discrete short length fibres. For instance, flavour additives could
be added in botanical form, such as mint or tobacco leaves or other
plant leaves, plant seeds, plant peel etc. Such additives can be
added to the additive hoppers in the band former of the Turmalin
apparatus and therefore metered into the filter material air stream
as the filter band is formed, for instance using discrete short
length cellulose acetate fibres as described herein. Since no
plasticiser is used in the randomly oriented discrete short length
fibre filter, flavour release from botanical additives can be
enhanced.
[0085] It is envisaged by the inventors that additional materials
not previously used in filter manufacturing may be used in
manufacture using a Turmalin apparatus or similar.
[0086] In one embodiment, shredded sheet materials, including new
sheet materials, are included within the filter material. Such
sheet materials include sheet materials formed from botanicals,
such as mint and or menthol, tobacco or reconstituted tobacco. A
person skilled in the art will appreciate that the list provided is
not limiting and that any suitable sheet material may be used. The
benefits of using such sheet materials in shredded form are that
they can improve the dispersibility of the material within the
filter and also improve the degradability of the filter material.
Furthermore, the use of new materials may be used to improve the
performance of the filter and/or modify characteristics of smoke
drawn through the filter.
[0087] FIG. 11 is a schematic illustration of a smoking article
having a filter comprising randomly oriented discrete short length
fibres having shredded sheet material disposed therein.
[0088] Referring to FIG. 11, the smoking article 211 comprises a
tobacco rod 212 wrapped in a wrapping material 213, in this case
cigarette paper, connected longitudinally to a filter 214 by
tipping material 215 overlaying the filter 214 and partially
overlaying the wrapping material 213. The filter 214 comprises a
first segment 216 at the mouth-end of the filter 214 comprising
crimped cellulose acetate tow 217 wrapped in a first plug wrap 218,
and a second segment 219 at the tobacco rod end of the filter 214
comprising absorbent material 220 in which shredded sheet material
221 is dispersed. The second segment 219 is wrapped in a second
plug wrap 222. In the present example the absorbent material 200
comprises randomly oriented discrete short length cellulose acetate
fibres and the shredded sheet material 221 comprises shredded
reconstituted tobacco sheet.
[0089] The shredded sheet material 221 can comprise a material
formed from fibres of cellulose acetate, polyvinyl alcohol (PVOH),
polylactic acid (PLA), poly(.epsilon.-caprolactone)(PCL), poly(1-4
butanediol succinate) (PBS), poly(butylene
adipate-co-terephthalate)(PBAT), starch based materials, paper,
aliphatic polyester materials or polysaccharide polymers and/or
combinations therefore.
[0090] The inventors have also appreciated the potential for
combining degradable or otherwise alternative fibres such as PVOH
fibres with conventional cellulose acetate fibres. PVOH is
typically not used in conventional filter manufacture because PVOH
cannot usually be crimped. The inclusion of PVOH or other
non-crimped fibres with another material, i.e. cellulose acetate,
mean that this problem can be overcome. Using such materials can
result in a filter with improved degradability and water
solubility. Other materials include
poly(.epsilon.-caprolactone)(PCL), poly(1-4 butane diol
succinate)(PBS), poly(butylene adipate-co-terephthalate)(PBAT),
starch based materials, paper, aliphatic polyester materials and
polysaccharide polymers.
[0091] Also, other crimped materials such as PLA can be combined
with conventional cellulose acetate fibres.
[0092] In one embodiment, in order to add PVOH or other non-crimped
fibres to a filter, or PLA or other crimped fibres to a filter, the
Turmalin feeder 22 is arranged to feed two ropes of raw filter
material into the cutter and randomiser 23. As such, the number of
processing steps is reduced by not first turning the material into
sheet material, and instead pulling the material straight in as
tow.
[0093] In addition, the number processing steps may be further
reduced if the step for turning material into tow material is
omitted. In such embodiments, there is further no requirement to
feed, cut and randomise the fibres. Rather, the PVOH, PLA or other
material in raw fibrous form can be mixed directly with a bag of
short staple cellulose acetate fibres lanced straight into the
Turmalin apparatus.
[0094] In another embodiment, PVOH fibres (or other non-crimped
fibres) or PLA fibres (or other crimped fibres) can be metered into
the filter tow in the filter bander 24 using one of the additive
hoppers described above.
[0095] FIG. 12 is a schematic illustration of a smoking article
having a filter comprising randomly oriented discrete short length
fibres having degradable fibres disposed therein. Referring to FIG.
12, the smoking article 231 comprises a tobacco rod 232 wrapped in
a wrapping material 233, in this case cigarette paper, connected
longitudinally to a filter 234 by tipping material 235 overlaying
the filter 234 and partially overlaying the wrapping material 233.
The filter 234 comprises a first segment 236 at the mouth-end of
the filter 234 comprising crimped cellulose acetate tow 237 wrapped
in a first plug wrap 238, and a second segment 239 at the tobacco
rod end of the filter 234 comprising absorbent material 240 in
which PVOH fibres 241 are dispersed. The second segment 239 is
wrapped in a second plug wrap 242. In the present example the
absorbent material 240 comprises randomly oriented discrete short
length cellulose acetate fibres.
[0096] Conventional filter manufacturing techniques manufacture
filter rods with a uniform density in a longitudinal direction. The
inventors have appreciated that it is possible to purposely provide
variable density along the length of the filter rod. In one
embodiment the density may be caused to vary such that when the
filter rod is cut into individual segments, the filter segment
comprises dense ends, and a centre portion of lower density. This
is advantageous as it does not rely on the tow crimp to hold fibres
in the filter.
[0097] FIG. 13a is a schematic illustration of a filter rod 245
comprising alternately arranged longitudinal regions 246 of higher
average density and regions 247 of lower average density. The
filter rod 245 can be used to produce multiple filter segments,
each comprising a homogeneous unit of filter material, for instance
varying only in density along its length, for use in smoking
article filters. For instance, the filter rod 245 can be cut at the
centre 248 of each of the regions 246 of higher average density
such that the resulting filter segments have `dense ends`. Line
graph 249 illustrates the density of filter material along the
length of the filter rod 245, in the present example varying in an
undulating or sinusoidal manner. In alternative examples, the
density of filter material along the length of the filter rod 245
can vary in other ways, for instance in a sequence of 1, 2, 3, 4 or
more stepped variations in the density for each density cycle along
the length of the filter rod 245. The filter material illustrated
in FIG. 13a comprises discrete short length cellulose acetate
fibres, but can alternatively be another fibrous filter material
described herein, such as polyvinyl alcohol (PVOH), polylactic acid
(PLA), poly(.epsilon.-caprolactone)(PCL), poly(l-4 butanediol
succinate) (PBS), poly(butylene adipate-co-terephthalate)(PBAT),
starch based materials, paper, aliphatic polyester materials and
polysaccharide polymers or combinations therefore. The material can
also contain additives, such as adsorbents as herein described.
[0098] The denser portions, as shown in FIG. 13a, are such that the
fibres, even if some or all of the fibres are not crimped, are
prevented from spilling out of filter segments, once cut. The
embodiment of FIG. 13a accordingly can enable the use of materials
which are not suitable for crimping, for example PVOH and non-woven
materials. This, in turn, can lead to increased degradability and
water solubility as described above. The filter material can
therefore be formed from a single fibrous material, or multiple
combined materials such as cellulose acetate fibres combined with
those of another material.
[0099] A person skilled in the art will appreciate different ways
in which the density of the filter rod 245 may be caused to vary
along its length. For example, this could be achieved by using
machinery having a variable speed garniture or pulsing higher
volumes of filter material, or additives, when forming filter
material onto a suction band. Alternatively or in addition, the
filter suction band can be adapted to enable regions of higher
average density and regions of lower average density to be formed
on the band, for instance by varying the air resistance of the band
in different regions such as by varying the size and/or frequency
of apertures on the band according to the desired density pattern.
The timing of the production line can be controlled such that the
segment lengths are controlled and cut accordingly.
[0100] FIG. 13b is a schematic illustration of a section of a
filter forming suction band, such as that used in the filter bander
24 of the Turmalin apparatus, for producing filter segments having
regions of higher average density and regions of lower average
density. Referring to FIG. 13b, the filter forming suction band 250
comprises a nylon mesh 251 formed so as to have first regions 252
having larger mesh apertures and a lower density of mesh material
and second regions 253 having smaller mesh apertures and a higher
density of mesh material. The first regions 252 accordingly have a
lower resistance to air than the second regions 253. In use, the
fibres in the filter bander air stream will be drawn towards the
first regions 252 having larger mesh apertures with greater force
than towards the second regions 253 having smaller mesh apertures.
As a result, a greater average density of filter fibres will be
deposited in the first regions 252 than in the second regions 253.
The resulting filter will therefore have regions of greater average
density corresponding to the first regions 252 of the suction band
250 and regions of lower average density corresponding to the
second regions 253 of the suction band 250.
[0101] In the example of FIG. 13b, the size and number of apertures
is varied along the length of the suction band 250 in an undulating
manner. However, in other embodiments, only the size of the
apertures can be varied along the length of the suction band, for
instance by using a solid band with varying aperture sizes cut into
the band at different longitudinally spaced repeating intervals.
Alternatively, in other embodiments, only the number of apertures
is varied along the length of the suction band, for instance by
using a solid band with varying numbers of apertures for a given
area of band cut into the band at different longitudinally spaced
repeating intervals along the band. Also, rather than following an
undulating variation in air resistance along the length of the
suction band, the apertures can be arranged such that 1, 2, 3, 4 or
more step changes in the density of filter material occur in
repeating intervals along the length of the band.
[0102] The inventors have also realised that it is possible to
create filters having a non-conventional cross-sections. In
conventional filter rods, if a non-circular shape was desired it
would require a substantial quantity of plasticiser and steam to
form the required shape. In practice this has not been readily
achievable. However, the inventors have appreciated that the way in
which the Turmalin apparatus creates an oblong band which has a
mechanical strength can be adapted for other cross-sectional shapes
of the filter material. For instance, the Turmalin apparatus could
be adapted to create a band other than an oblong or the filter
material can be forced into a desired shape, for instance via a
shaped aperture or using an appropriately shaped garniture belt.
For example, the band of filter material may be formed on the belt
of the filter bander 24 or passed through an appropriately shaped
aperture or garniture belt, such that the filter has a polygonal,
for instance triangular, square, rectangular, pentagonal or
hexagonal cross-section, or another non-circular cross-section,
such as an oval or elliptical cross-section, and the structural
stability of the band of material can be such that the band
maintains the desired shape. Another embodiment may make use of
appropriately designed wrapping and steaming processes. The
resulting filter may have a cross section with a circumference
smaller than 16 mm or a circumference greater than 25 mm.
[0103] FIG. 14 is a schematic illustration of a smoking article 291
having a filter comprising an elliptical cross-section.
[0104] Referring to FIG. 14, the smoking article 291 comprises an
elliptically cross-sectioned tobacco rod 292 wrapped in a wrapping
material 293, in this case cigarette paper, connected
longitudinally to a filter 294 by tipping material 295 overlaying
the filter 294 and partially overlaying the wrapping material 293.
The filter 294 comprises a single filter segment 296 at the
mouth-end of the smoking article 291 comprising absorbent material
297 wrapped in a first plug wrap 2980. The segment 296 has an
elliptical cross-section. In the present example the absorbent
material 297 comprises randomly oriented discrete short length
cellulose acetate fibres. An additional plastic mesh, a fabric, or
other permeable barrier (not shown) can be applied across the
mouth-end of the filter 294 to prevent individual filter fibres
from coming away from the filter 294.
[0105] FIG. 15 is a schematic illustration of a smoking article 311
having a filter comprising a square cross-section.
[0106] Referring to FIG. 15, the smoking article 311 comprises a
square cross-sectioned tobacco rod 312 wrapped in a wrapping
material 313, in this case cigarette paper, connected
longitudinally to a filter 314 by tipping material 315 overlaying
the filter 314 and partially overlaying the wrapping material 313.
The filter 314 comprises a single segment 316 at the mouth-end of
the smoking article 311 comprising absorbent material 317 wrapped
in a plug wrap 318. The segment 316 has a square cross-section. In
the present example the absorbent material 317, 320 comprises
randomly oriented discrete short length cellulose acetate fibres.
An additional plastic mesh, a fabric, or other permeable barrier
(not shown) can be applied across the mouth-end of the filter 314
to prevent individual filter fibres from coming away from the
filter 314.
[0107] The filters 294, 314 of the embodiments illustrated in FIGS.
14 and 15 can also include other features, such as additives
dispersed within the filter fibres and/or ventilation applied to
the filters, for instance as laser formed holes.
[0108] The inventors have also realised that it is possible to
produce filters including randomly orientated short-length fibres
formed into a cylinder having a circumference smaller than 16 mm,
15 mm, 14 mm or 13 mm, or a circumference greater than 25 mm, 26
mm, 27 mm or 28 mm. A single denier fibre can be used, for instance
having a denier from about 7 to about 9, and the amount used in the
filter per mm varied according to the filter circumference
required. For instance, the amount of randomly orientated
short-length fibres per mm can be reduced for super slim format
filters and increased for regular format filters. This differs from
known continuous tow filter manufacture where different fibre
deniers are usually required for different circumference
filters.
[0109] In the foregoing examples, the second filter segments 9, 39,
59, 159, 179, 199, 219 and 239 (shown in FIGS. 1 and 6 to 12)
containing randomly oriented discrete length fibres have been
described as tobacco-end components of dual filters, with known
cellulose acetate first filter segments at the mouth-end. However,
other arrangements are possible. For instance, the second segments
can be adapted for use at the mouth end of cigarette filters. This
can be achieved by preventing individual fibres from coming away
from the filter segment during use, for instance by including a
plasticiser (for instance a localised plasticiser in a portion at
the mouth end of the mouth-end segment) to hold the randomly
oriented discrete length fibres and/or any additives dispersed
therein in place, or by using a plastic mesh, a fabric, or other
permeable barrier preventing individual fibres from reaching the
mouth of a consumer. The second filter segments can also be used as
the central or tobacco-end filter segment of a three-part filter,
or any segment of a four, five or six-part filter, as required. The
first filter segments can also be other than conventional cellulose
acetate segments wrapped in plug wrap. For instance, non-wrapped
acetate (NWA) sections can be used as the first filter segments
described herein.
[0110] Also, the first and second filter segments of the
embodiments illustrated in FIGS. 1 and 6 to 12 have been shown to
have individual plug wraps and be held together and connected to
the tobacco rod using a tipping material. However, alternatively, a
further outer plug wrap (not shown) can be wrapped around the first
and second filter segments and used to connect the first and second
filter segments to each other, and the combined filter unit can
then be connected to the tobacco rod using a tipping material.
[0111] Although the randomly oriented fibres described herein have
been described as being crimped, non-crimped fibres can also be
used, alone or mixed with crimped fibres. Also, the randomly
oriented fibres have been described as being of 10 mm fibre lengths
(when extended), or lengths in the range from 5 mm to 25 mm, or
from 6 mm to 20 mm, 7 mm to 20 mm or 7 mm to 15 mm. The second
segments can also include average fibre lengths outside this range,
and/or mixtures of groups fibres of different average lengths,
depending on the requirement of the filter concerned and the
fibrous materials available.
[0112] Filter arrangements described herein can be modified to
include one or more transparent sections in the plug wrap and/or
tipping paper so as to allow the internal filter parts to be seen
by smoking article consumers. For instance, the second plug wrap
used to wrap the second filter segment may comprise a transparent
material such as Natureflex.TM. film available from Innovia Films
in the United Kingdom. The tipping could comprise one or more
window cut-outs, or sections of transparent material such as
Natureflex.TM. film, to enable the internal filter parts to be seen
through the tipping and plug wrap. Alternatively, the tipping could
be applied in two bands with a gap between them revealing the
transparent plug wrap beneath, or the tipping could be made
entirely of a material such as Natureflex.TM. film. Some
embodiments may include transparent `window` section filters such
as those described in patent publication no. WO2009/106374, the
contents of which (including any corresponding US publications) are
incorporated by reference in their entirety herein.
[0113] In order to address various issues and advance the art, the
entirety of this disclosure shows by way of illustration various
embodiments in which the claimed invention(s) may be practiced and
provide for superior smoking article filters. The advantages and
features of the disclosure are of a representative sample of
embodiments only, and are not exhaustive and/or exclusive. They are
presented only to assist in understanding and teach the claimed
features. It is to be understood that advantages, embodiments,
examples, functions, features, structures, and/or other aspects of
the disclosure are not to be considered limitations on the
disclosure as defined by the claims or limitations on equivalents
to the claims, and that other embodiments may be utilised and
modifications may be made without departing from the scope and/or
spirit of the disclosure. Various embodiments may suitably
comprise, consist of, or consist essentially of, various
combinations of the disclosed elements, components, features,
parts, steps, means, etc. In addition, the disclosure includes
other inventions not presently claimed, but which may be claimed in
future.
* * * * *