U.S. patent application number 16/340917 was filed with the patent office on 2020-02-06 for filters for smoking articles for less additive(s) loss.
This patent application is currently assigned to JT International S.A.. The applicant listed for this patent is JT International S.A.. Invention is credited to Noritoshi Fujita.
Application Number | 20200037659 16/340917 |
Document ID | / |
Family ID | 57629324 |
Filed Date | 2020-02-06 |
![](/patent/app/20200037659/US20200037659A1-20200206-D00001.png)
United States Patent
Application |
20200037659 |
Kind Code |
A1 |
Fujita; Noritoshi |
February 6, 2020 |
Filters For Smoking Articles For Less Additive(s) Loss
Abstract
Improvements are provided in filters for use in smoking
articles, including the use of randomly oriented discrete fibres.
The improvements mainly relate to the loss of additive(s) in said
filters and to the manufacture thereof. In one embodiment, a filter
for a smoking article includes randomly oriented discrete fibres
and at least one particulate additive, the at least one particulate
additive being dispersed within the filter, wherein a value
obtained by dividing a volume fraction of the at least one
particulate additive by a volume fraction of the fibres is less
than about 1100%.
Inventors: |
Fujita; Noritoshi;
(Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JT International S.A. |
Geneva |
|
CH |
|
|
Assignee: |
JT International S.A.
Geneva
CH
|
Family ID: |
57629324 |
Appl. No.: |
16/340917 |
Filed: |
December 8, 2017 |
PCT Filed: |
December 8, 2017 |
PCT NO: |
PCT/EP2017/082022 |
371 Date: |
April 10, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/062 20130101;
A24D 3/163 20130101; A24D 3/063 20130101; A24D 3/048 20130101; A24D
3/10 20130101 |
International
Class: |
A24D 3/16 20060101
A24D003/16; A24D 3/06 20060101 A24D003/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2016 |
EP |
16205034.8 |
Claims
1. A filter for a smoking article comprising randomly oriented
discrete fibres and at least one particulate additive, the at least
one particulate additive being dispersed within the filter, wherein
a value obtained by dividing a volume fraction of the at least one
particulate additive by a volume fraction of the fibres is less
than about 1100%.
2. The filter according to claim 1, wherein a range of a combined
loading amount of the at least one particulate additive and the
fibres is between 2.4 mg/mm and 19 mg/mm.
3. The filter according to claim 2, wherein the range of the
combined loading amount of the at least one particulate additive
and the fibres is 11 mg/mm to 13 mg/mm.
4. The filter according to claim 1, wherein the at least one
particulate additive is provided in an amount of between 1 mg/mm
and 13.5 mg/mm.
5. The filter according to claim 4, wherein the amount of the at
least one particulate additive is in the range of from 8 mg/mm up
to 10 mg/mm.
6. The filter according to claim 1, wherein the fibres are provided
in an amount of between 1.4 mg/mm and 5.5 mg/mm.
7. The filter according to claim 6, wherein the amount of fibres is
in the range of from 3.0 mg/mm up to 3.5 mg/mm.
8. The filter according to claim 1, wherein the at least one
particulate additive comprises or is charcoal.
9. The filter according to claim 1, wherein the fibres have a
filament denier in the range of from 3.0 D to 12.0 D.
10. The filter according to claim 1, wherein the filter has a
cylindrical shape with a circumference of the cylinder being equal
to or smaller than 26 mm.
11. A smoking article comprising a filter according to claim 1.
12. A method of producing a filter for a smoking article,
comprising: adding randomly oriented fibres and at least one
particulate additive to the filter, wherein the at least one
particulate additive is dispersed in the filter, wherein a value
obtained by dividing a volume fraction of the at least one
particulate additive by a volume fraction of the fibres is less
than about 1100%.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to improvements in filters for
use in smoking articles, comprising randomly oriented discrete
fibres. The improvements mainly relate to the loss of additive(s)
in said filters and to the manufacture thereof.
BACKGROUND TO THE INVENTION
[0002] In conventional filter cigarettes, the filter commonly
consists of a single segment of filtration material, typically a
continuous tow of filamentary cellulose acetate plasticised with
triacetin, circumscribed by porous and/or non-porous plug wrap. 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.
[0003] In the past it has been proposed to replace the continuous
tow with randomly oriented discrete fibres of cellulose acetate.
The advantages of using such kind of fibres have been reported and
listed in several publications, like WO 2009/080368, WO
2009/093051, WO 2013/068337, WO 2013/164624 and WO 2013/164623.
Filter manufacturing machines specifically developed for making
such kind of filters are also known, e.g. Turmalin machine made by
Hauni Maschinenbau AG, Germany.
[0004] With randomly oriented discrete fibres, filters having
higher additive loadings can be produced compared to filters using
continuous tow. In addition to this, the Turmalin machine is
reported as allowing said higher loadings without using any
plasticizer such as triacetin, e.g. in WO 2013/164624 and WO
2013/164623.
[0005] However, all publications are silent on how to process
filters having said higher additive loading. Indeed, the present
inventors have found that as soon as filters comprising randomly
oriented discrete fibres and high additive loading are cut in order
to form individual filter segments or to be assembled in multiple
segments filters, a very significant amount of the additive is
lost.
[0006] Therefore, there is a need to provide filters comprising
randomly oriented discrete fibres and a stable, long lasting high
additive loading with good performance of the additive, as well as
smoking articles with these filters.
SUMMARY OF THE INVENTION
[0007] The inventors identified particulate additive, e.g. granule,
loss during the combining process as a problem in terms of filter
quality and machinability for the usage of granulated filters with
high loadings of additives like granules and randomly oriented
fibres, e.g. randomly oriented acetate (ROA) fibres. With regard to
filter quality, pressure drop in the filter and filter burst are
significantly affected by granule loss.
[0008] An exemplary filter has a circumference of 23.9 mm and a
filter length of 120 mm, and contains 2.2 mg/mm filter tow. 13
mg/mm of charcoal granules are added as additive. This results in a
target pressure drop (PD) of 318 mmWG/rod (mm water gauge/rod; 3118
Pa/rod).
[0009] A 10 wt. % granule loss in the above exemplary filter
results in a pressure drop of 287 mmWG/rod, resulting in a 10%
pressure drop loss compared to the target pressure drop. This is
not acceptable with regard to cigarette design.
[0010] Similarly, a 5 wt. % granule loss results in a pressure drop
of 303 mmWG/rod, resulting in 5% PD loss. This could for example be
seen as an upper limit with regard to cigarette design/quality.
[0011] In addition, loose granules can accumulate at the seam of
the combiner plug wrap used to attach a plurality of filter
segments. This may even prevent seam formation as the loose
granules reduce the effective area for the adhesive that is
typically applied to form the seam. As a result, the filter may
burst open. The inventors have identified that this problem
increases with increased loss of granules.
[0012] Furthermore, having regard to machinability, charcoal
contamination around the machine is a problem that can lead to
machine stoppage. To mitigate this problem special protections have
been installed to ensure that charcoal does not accumulate in
problematic areas, such as the plug wrap gluing and guiding system,
and frequent machine cleaning is necessary.
[0013] Therefore, a target for additive loss, e.g. granule loss,
should be for example less than about 5%, based on the total weight
of the additive, to keep a good filter quality and
machinability.
[0014] The inventors found that an improvement in additive loss,
i.e. decreased loss of at least one particulate additive, can be
achieved by a filter for a smoking article comprising a certain
amount of fibres and a certain amount of additive.
[0015] Thus, a first aspect of the invention provides a filter for
a smoking article comprising randomly oriented discrete fibres and
at least one particulate additive, the additive being dispersed
within the filter, wherein the value obtained by dividing the
volume fraction of the additive (cc/mm) by the volume fraction of
the fibres (cc/mm) is less than about 1100%.
[0016] Furthermore, the invention relates to a smoking article
comprising the filter of the present invention.
[0017] Further preferred and exemplary embodiments of the invention
are indicated in the dependent claims and the following detailed
description, which, however, do not restrict the scope of the
invention and only help to understand and explain the features of
the present invention. Deviations and modifications on these
particular features, particular in regard to other aspects of the
invention, can be made without departing from the scope of the
invention.
DESCRIPTION OF FIGURES
[0018] The invention will be further described in detail in the
following with reference to the figures and particular embodiments
thereof, without being limited thereto.
[0019] In the figures the following is shown:
[0020] FIG. 1 shows a graph of exemplary data taken from the
Examples.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0021] All ranges disclosed herein are to be considered to be
supplemented by the term "about", unless clearly defined to the
contrary or otherwise clear from the context.
[0022] All numbers or percentages relating to amounts of a
substance within this application are given in wt. %, unless
clearly defined to the contrary or otherwise clear from the
context.
[0023] The term "randomly oriented discrete fibres" refers to a
plurality of fibres that can be distinguished from each other and
are physically separated, i.e. discrete fibres. They are randomly
oriented in three directions, i.e. form a random 3-dimensional
fibre network wherein the fibres are directed in any direction,
without all fibres being directed in the same direction. The fibres
can have different lengths or have the same lengths as well as the
same diameter or different diameters, and can be uniform or
non-uniform with regard to their individual sizes and shapes.
[0024] The term "smoking article" relates to all kinds of smokable
products like cigarettes, cigars, cigarillos, etc. In these smoking
articles, the kind of smokable material used, e.g. tobacco, tobacco
derivatives, expanded tobacco, reconstituted tobacco, tobacco
substitutes, non-burnable products, etc., as well as mixtures
thereof, is not particularly limited. These smoking articles are
provided with a filter according to the invention.
[0025] Smoking articles and their formats can be e.g. characterized
according to the cigarette length, with "regular" being in the
range 68-75 mm, e.g. from about 68 mm to about 72 mm, "short" or
"mini" being 68 mm or less, "king-size" being in the range 75-91
mm, e.g. from about 79 mm to about 88 mm, "long" or "super-king"
being in the range 91-105 mm, e.g. from about 94 mm to about 101
mm, and "ultra-long" being in the range from about 110 mm to about
121 mm.
[0026] They can also be characterized by the circumference of the
smoking article, e.g. a cigarette, with "regular" having a
circumference of about 23-25 mm, "wide" having a circumference of
greater than 25 mm, "slim" having a circumference of about 22-23
mm, "demi-slim" having a circumference of about 19-22 mm,
"super-slim" having a circumference of about 16-19 mm, and
"micro-slim" having a circumference of less than about 16 mm.
[0027] 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 have
e.g. a circumference of from 23 to 25 mm and an overall length of
from 75 to 91 mm.
[0028] 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 to 30 mm. The tipping paper can have a greater length
than the filter, for example from 3 to 10 mm longer.
[0029] A particulate additive is an additive that is present in the
form of particles, i.e. particularly in solid form. The particulate
additive(s) can be e.g. in powder (particle diameter of about 50 to
150 .mu.m) and/or granular form (particle diameter of about 150 to
1000 .mu.m).
[0030] According to one aspect, the present invention relates to a
filter for a smoking article comprising randomly oriented discrete
fibres and at least one particulate additive, the (particulate)
additive being dispersed within the filter, wherein the value
obtained by dividing the volume fraction of the (particulate)
additive(s) (cc/mm) by the volume fraction of the fibres (cc/mm) is
less than about 1100%, for example less than about 1000%, such as
less than about 900%, e.g. less than about 800%.
[0031] The volume fraction herein is the ratio of a volume of a
certain material, e.g. the particulate additive and/or the randomly
oriented discrete fibres, to the total available volume in the
filter. The volume of a certain material can thereby be calculated
using the bulk density of the material and the weight thereof. The
total volume of a filter can be determined by consideration of the
shape of the filter, e.g.--in case of a cylindrical filter--using
the diameter and length. Suitable measurement procedures for the
bulk density of the particulate additive are known from ASTM
D2854-2009 for granular activated carbon, ASTM D1895 test method A
for fine granules and powders that can be poured readily through a
small funnel (e.g. silica granule, hydrotalcite, paper granule,
acetate flake, or coffee granule), ASTM D1895 test method B for
coarse granular materials, including dice and pellets, that either
cannot be poured or that are poured with difficulty through the
funnel described in ASTM D1895 test method A (e.g. tobacco granule,
sugar granule), and ASTM D1895 test method C for materials supplied
in the form of coarse flakes, chips, cut fibres, or strands (e.g.
mint leaf, tobacco leaf). A suitable measurement procedure for the
bulk density of the randomly oriented discrete fibres is known from
ASTM D3887-1995.
[0032] By keeping a certain ratio between the volume fraction of
the additive(s) and the volume fraction of the fibres, it is
possible to minimize the loss of additive, e.g. resulting from
cutting during preparation of the filters, e.g. cutting the filters
to a certain desired length of e.g. 3 to 20 mm, e.g. 6 to 12 mm, or
e.g. 8 to 10 mm. Individual filter segments, or segments for
multiple segments filters, can be formed by cutting. According to
certain embodiments, the loss weight of the
additive(s)--particularly during cutting--is less than 5%, e.g.
less than 4.5%, e.g. less than 4%, e.g. less than 3%, based on the
total weight of the additive(s). The weight loss can be determined
by weighing using usual procedures. One example is to determine the
weight difference between the weight of a certain filter before
cutting and the total combined weight of cut filter segments--cut
from this filter--after cutting. Especially, according to certain
embodiments, it should be ensured that no loss is obtained due to
cutting in any other components of the filter, e.g. the randomly
oriented discrete fibres and/or a wrapping material, which can be
ensured by collecting losses of such other components, if
occurring, weighing them and adding this weight to the combined
weight of the cut filter segments, before this total combined
weight is subtracted from the weight of the filter before cutting.
According to certain embodiments, loss of other components, e.g.
filter tows, during cutting is negligible. According to certain
embodiments, the loss of additive is substantially due to the at
least one particulate additive, e.g. due to the at least one
particulate additive.
[0033] Thus, the present invention also relates to a process of
producing a filter for a smoking article according to the present
invention, as described below.
[0034] The dispersion of the at least one particulate additive in
the filter is not particularly limited and can be in any form. It
can for example be a homogeneous or heterogeneous dispersion within
the filter, e.g. the randomly oriented discrete fibres, and/or also
at other locations between the randomly oriented discrete fibres
and another material, e.g. a filter wrapping material.
[0035] The filter of the invention can contain one or more
particulate additive(s) which are not particularly limited and can
be those particulate additives normally used in filters for smoking
articles. Examples of suitable particulate additives include
flavourants or sorbents--e.g. activated carbon/charcoal, zeolite,
ion exchange resin, magnesium silicate like sepiolite, silica gel,
alumina, molecular sieves, carbonaceous polymer resins and
diatomaceous earths, or combinations thereof. Also, other
additives, such as humectants, can be used. According to certain
aspects, the particulate additive comprises or is
charcoal/activated carbon. According to certain embodiments, the at
least one particulate additive has a particle size from 50 to 2000
.mu.m, e.g. from 100 to 1000 .mu.m, as determined e.g. using sieve
analysis.
[0036] The material of the randomly oriented discrete fibres, which
can be comprised in or be the filter tow material, is not
particularly limited and can include a material that is typically
used in filters for smoking articles, e.g. cigarette filters. It
can include natural fibre materials which can be e.g. produced from
cellulose, herb materials like tobacco, or synthetic materials like
polypropylene. For example, the material of the randomly oriented
discrete fibres can comprise or be cellulose acetate or
polypropylene. Also mixtures of two or more fibre materials are
possible. According to certain aspects, the filter tow material may
have a filament denier in the range of from 3.0 up to 12.0 D, e.g.
of between 4.0 and 10.0 D, e.g. of between 5.0 and 8.0 D, e.g. of
about 6.0 D.
[0037] According to certain embodiments, the range of the combined
loading amount of the additive and the fibre is between 2.4 mg/mm
and 19 mg/mm for a filter of any diameter, e.g. having a diameter
between the lower limit for a super-slim size and the upper limit
of a regular size, i.e. between 16 and 25 mm. According to certain
embodiments, the range of the combined loading amount of the
additive and the fibre is between 3 mg/mm and 18 mg/mm, e.g.
between 8 mg/mm and 17 mg/mm. According to certain embodiments, the
range of the combined loading amount of the additive and the fibre
is between 8 mg/mm and 17 mg/mm, particularly for a regular
circumference filter, i.e. a circumference of 23 to 25 mm, e.g. 23,
23.9, 24 or 25 mm. According to further embodiments, the range of
the combined loading amount of the additive and the fibres is 9
mg/mm to 16 mg/mm, e.g. 10 mg/mm to 14.5 mg/mm, e.g. 10.5 mg/mm to
14 mg/mm, e.g. 11 mg/mm to 13 mg/mm, particularly for a regular
circumference filter, i.e. a circumference of 23 to 25 mm, e.g. 23,
23.9, 24 or 25 mm.
[0038] According to certain embodiments, the amount of the additive
is between 1 mg/mm and 13.5 mg/mm for a filter of any diameter,
e.g. having a diameter between the lower limit for a super-slim
size and the upper limit of a regular size, i.e. between 16 and 25
mm. According to certain embodiments, the amount of the additive is
between 6 mg/mm and 13 mg/mm. According to certain embodiments, the
amount of the additive is in the range between 7 mg/mm and 12
mg/mm, e.g. in the range between 7.5 mg/mm and 11 mg/mm, e.g. in
the range of from 8 mg/mm up to 10 mg/mm, particularly for a
regular circumference filter, i.e. a circumference of 23 to 25 mm,
e.g. 23, 23.9, 24 or 25 mm.
[0039] According to certain embodiments, the amount of fibres is
between 1.4 and 5.5 mg/mm for a filter of any diameter, e.g. having
a diameter between the lower limit for a super-slim size and the
upper limit of a regular size, i.e. between 16 and 25 mm. According
to certain embodiments, the amount of fibres is between 2.0 and 4.5
mg/mm, e.g. between 2.0 and 4.0 mg/mm, e.g. between 2.2 mg/mm and
3.8 mg/mm, e.g. between greater than 2.2 mg/mm and up to 3.7 mg/mm.
According to certain embodiments, the fibre loading amount is in
the range of from 2.5 mg/mm to 3.6 mg/mm, e.g. from 2.8 mg/mm to
less than 3.6 mg/mm, e.g. in the range from 3.0 mg/mm up to 3.5
mg/mm, particularly for a regular circumference filter, i.e. a
circumference of 23 to 25 mm, e.g. 23, 23.9, 24 or 25 mm.
[0040] According to certain embodiments, the amount of the additive
is between 6 mg/mm and 13 mg/mm, and/or the amount of fibres is
between 2.0 and 4.0 mg/mm, e.g. between 2.2 mg/mm and 3.8 mg/mm,
e.g. between greater than 2.2 mg/mm and up to 3.7 mg/mm,
particularly for a regular circumference filter, i.e. a
circumference of 23 to 25 mm, e.g. 23, 23.9, 24 or 25 mm.
[0041] The filter of the invention can have any shape and is not
particularly limited, but is preferably in a shape commonly used in
smoking articles, e.g. in cylindrical shape. According to certain
embodiments, the filter has a cylindrical shape with a
circumference of the cylinder being equal to or smaller than 26 mm,
preferably equal to or smaller than 23.9 mm.
[0042] Further, the filter of the invention may optionally include
other materials, for example one or more liquid(s) (such as a
flavourant, e.g. menthol solution).
[0043] In addition, the present filter is also not particularly
limited regarding other components of the filter and can include
components that are commonly used in filters for smoking articles.
For example, the filter may be wrapped with a wrapper or plug wrap,
for example a wrapper of paper, e.g. an air-permeable paper.
Particulate additives as discussed above can also be applied to the
wrapper or plug wrap surrounding the filter material. The material
of the plug wrap is not particularly limited and can comprise paper
and/or plastic materials like PE, PP, etc.
[0044] According to certain embodiments, the filter of the present
invention does not contain a binder or a plasticizer, making
processing and manufacturing of the filter easier. A binder may
have the disadvantage that it solidifies after application, which
leads to contamination in the process and a higher pressure drop. A
plasticizer like triacetin can, especially at high loading, lead to
melt holes in the filter, i.e. dissolve the filter tow, causing
defect in the smoking article. Even without using a binder or a
plasticizer, additive loss in the present filter can be
reduced.
[0045] According to certain embodiments, the filter comprising
randomly oriented discrete fibres and the additive is cut into
desired lengths in order to form individual filter segments or to
be assembled to multiple segments filters. In such a case--by
determining the weight difference between the filter before and
after cutting, resulting from the loss of additive during cutting,
e.g. to a length of 6 mm--the loss weight of the additive can be
less than about 5%, e.g. less than about 4.5%, e.g. less than about
4%, e.g. less than about 3%, based on the total weight of the
additive.
[0046] In a further aspect, the present invention relates to a
smoking article comprising the filter of the present invention. The
smoking article is not particularly limited and can be e.g. a
cigarette, a cigar or a cigarillo in any size and shape. In such a
smoking article, also two or more of the filters according to the
invention can be used, and/or the present filter can be used in
combination with another filter, e.g. in a segmented filter.
Regarding the further composition, the smoking article of the
invention is not limited. As a matter of course, a tobacco
containing segment can be contained in the smoking article, wherein
the tobacco is not limited, and the smoking article can e.g. be
wrapped using usual material, and can also contain other components
like a tipping paper.
[0047] In a further aspect, the present invention also relates to a
method of producing/manufacturing a filter for a smoking article,
particularly according to the present invention, wherein at least
one particulate additive and randomly oriented fibres are provided
and added to a filter for a smoking article, wherein the at least
one particulate additive is dispersed in the filter, wherein the
value obtained by dividing the volume fraction of the additive
(cc/mm) by the volume fraction of the fibres (cc/mm) is less than
about 1100%.
[0048] The filter of the present invention may be manufactured by
known methods, using common equipment, e.g. a Turmalin machine from
Hauni, Del. The at least one particulate can be, for example added
into the filter tow, i.e. the randomly oriented discrete fibres,
and then the tow is shapes into e.g. a rod of any desirable
circumference. The e.g. cylindrical rod formed to any desired size
and shape may be wrapped in a plug wrap and sealed with an adhesive
by means that are well-known in the prior art, e.g. using spiral
anchor glue. Afterwards, the filter rod can further be cut into
desired lengths using known methods. Other additives, if included,
can be introduced at suitable times in the filter production
process.
[0049] Using the filter of the present invention, a smoking article
can be produced, e.g. by combining one or more filters of the
invention with a tobacco rod and optionally other filters, and
wrapping the resultant, e.g. by methods known in the art.
EXAMPLES
[0050] The present invention will now be described with reference
to examples thereof, without limiting the scope of the invention to
these particular examples.
Example 1
[0051] In the following, different filters for cigarettes were
produced with different loadings of additive and different loadings
and sizes of randomly oriented discrete fibres (hereinafter also
referred to as filter tow).
[0052] The controllable parameters were herein as follows:
[0053] Charcoal loading: 8-13 mg/mm
[0054] Filter tow loading: 2.0-3.5 mg/mm
[0055] Filter tow cut length: 10-20 mm
[0056] Furthermore, the following parameters were given for
production. Cylindrical base filters were produced with a
circumference of 23.9 mm and a length of 120 mm length, which were
then wrapped with a non-porous plug wrap. After wrapping, the base
filter was cut 19 times to obtain equal cut filters, each with a
final length of 6 mm. For anchor glue application, a spiral glue
application was used.
[0057] Charcoal was supplied from JacobiCarbons (Sweden). It had a
bulk density of 603 kg/m.sup.3, a CCl.sub.4 adsorption of 60-70%,
and an ASTM Mesh size of 30.times.60 (595 .mu.m.times.250 .mu.m).
For the present charcoal, the bulk density was determined by ASTM
D2854-2009.
[0058] Filter tow, i.e. randomly oriented discrete fibres, was
obtained from Celanese. It had the following properties: Denier per
Filament (g/9000m) was 6.0 D, and total Denier (g/9000 m) was 17000
D, with the cross Section being Y. The bulk density was 1255
kg/m.sup.3 measured according to ASTM D3887-1995.
[0059] As a plug wrap, a wrap from Delfort with a porosity
(cm.sup.3/cm.sup.2/min) of 0 (i.e. without pores), a basis weight
of 27 g/m.sup.2, and a thickness of 43 .mu.m was used.
[0060] Base rod making of base filter rods was carried out with a
Turmalin base rod maker, supplied by Hauni, Del., at a machine
speed of 200 m/min, to obtain base filter rods/base filters with a
length of 120 mm.
[0061] These base filters were then introduced into a combining
process, using a Solaris (Combiner) from ITM working at a machine
speed of 350 m/min.
[0062] The following additive loss test has been carried out:
[0063] 1. Before entering into the combining process, selected base
filter rods were separately color-coded by colour application to
the outside (using a coloured pen), and weighed.
[0064] 2. The base filter rods were then introduced into the
combining process and processed, wherein the base filter rods were
cut from the original length of 120 mm to a target length of 6
mm.
[0065] 3. After the combining process, the coloured & cut
filters, i.e. filter tips, were collected, and cut filters with the
same colour, i.e. coming from the same base filter rod, were
combined.
[0066] 4. These combined, cut filter rods were weighed, and the
weight was compared to the weight of the base filter rod with the
same colour, the weight difference representing loss in the
combining process. It was confirmed visually that substantially no
other losses but charcoal losses arose in the combining process,
and further losses, if occurring, were negligible.
[0067] The results for several filters of comparative examples
(Comp. Ex.) and examples (Ex.) with different charcoal and filter
tow loading and different length of the fibres, after cutting the
base filter rods, with regard to additive loss are given in Table
1. Standard deviations (STDEV) were calculated for 15 samples in
each example, respectively comparative example, using the Excel
function "stdev".
TABLE-US-00001 TABLE 1 Product parameter Additive loss Charcoal
Filter tow FT cut Average STDEV Example mg/mm (FT) mg/mm length mm
% % Comp. Ex 1-1 13 2.1 10 9.1 1.1 Comp. Ex 1-2 13 2.2 10 7.3 1.0
Ex. 1-1 10 3.0 10 2.7 1.5 Ex. 1-2 8 3.5 10 1.9 1.4 Comp. Ex 1-3 13
2.1 20 9.1 1.4 Comp. Ex 1-4 13 2.2 20 9.6 1.7 Ex. 1-3 10 3.0 20 2.7
1.4 Ex. 1-4 8 3.5 20 2.4 0.8
[0068] Selected values from Table 1 are shown in FIG. 1, wherein
the x-axis represents the ratio of the volume fraction of charcoal
.PHI..sub.C divided by the volume fraction of fibres .PHI..sub.F,
and the y-axis represents the charcoal loss L.sub.C. Examples with
a fibre length of 10 mm are represented with an empty circle,
whereas examples with a fibre length of 20 mm are represented with
a rhombus. As can be seen, a significant reduction in charcoal loss
was observed when keeping the ratio .PHI..sub.C/.PHI..sub.F below a
certain value, e.g. less than about 1000% if the charcoal loss is
to be limited to about 5% or less, based on the total weight of the
charcoal.
[0069] When comparing the results represented in FIG. 1, it was
observed that shortening fibre length has a slight influence in
additive loss reduction. It is expected that by further reducing
fibre length, e.g. to 5 mm, additive loss will be limited to about
5% or less by keeping the ratio .PHI..sub.C/.PHI..sub.F below
1100%.
[0070] With the present filter, a significant reduction in
additive(s) can be achieved, resulting in cigarettes with improved
pressure drop and a manufacturing process that requires less
cleaning due to such losses.
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