U.S. patent application number 16/655770 was filed with the patent office on 2020-02-13 for filter materials and filters made therefrom.
The applicant listed for this patent is British American Tobacco (Investments) Limited. Invention is credited to Martin Dauner, Andrew Davis, Barry Dimmick, Yahia LEMMOUCHI, Christoph Rieger, Andreas Ullrich.
Application Number | 20200046016 16/655770 |
Document ID | / |
Family ID | 50239240 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200046016 |
Kind Code |
A1 |
LEMMOUCHI; Yahia ; et
al. |
February 13, 2020 |
FILTER MATERIALS AND FILTERS MADE THEREFROM
Abstract
The present invention relates to filter material for inclusion
in a smoking article, said filter material comprising a base
material comprising or made from fibres having a first diameter or
mean diameter, and fine fibres having a diameter or mean diameter
which is smaller than the first diameter, wherein the filter
material comprises more than 10% by weight and/or by volume fine
fibres or wherein the diameter or mean diameter of the fine fibres
is between about 1.0 .mu.m and about 1.5 .mu.m. The invention also
relates to filters or filter elements comprising the filter
material, smoking articles comprising the same, and use of the
filter material in smoke filtration.
Inventors: |
LEMMOUCHI; Yahia; (London,
GB) ; Davis; Andrew; (London, GB) ; Dimmick;
Barry; (London, GB) ; Dauner; Martin;
(Denkendorf, DE) ; Rieger; Christoph; (Denkendorf,
DE) ; Ullrich; Andreas; (Denkendorf, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
British American Tobacco (Investments) Limited |
London |
|
GB |
|
|
Family ID: |
50239240 |
Appl. No.: |
16/655770 |
Filed: |
October 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15113433 |
Jul 21, 2016 |
|
|
|
PCT/GB2015/050127 |
Jan 21, 2015 |
|
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|
16655770 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/063 20130101;
A24D 3/0275 20130101; A24D 3/10 20130101; A24D 3/068 20130101; A24D
3/027 20130101; A24D 3/04 20130101; B01D 39/18 20130101 |
International
Class: |
A24D 3/06 20060101
A24D003/06; A24D 3/04 20060101 A24D003/04; A24D 3/10 20060101
A24D003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2014 |
GB |
1400990.6 |
Claims
1.-15. (canceled)
16. A filter material for inclusion in a smoking article, wherein
the filter material comprises: a base material comprising
polylactide (PLA) and in the form of a sheet; and fibres comprising
cellulose acetate and in the form of a thread.
17. The filter material according to claim 16, wherein the filter
material comprises fine fibres having a diameter or mean diameter
of between about 0.5 .mu.m and about 10 .mu.m.
18. The filter material according to claim 17, wherein the filter
material comprises at least about 1% by weight fine fibres.
19. The filter material according to claim 17, wherein the filter
material comprises at least about 1% by volume fine fibres.
20. The filter material according to claim 16, wherein the fibres
consist essentially of cellulose acetate.
21. The filter material according to claim 16, wherein the base
material consists essentially of PLA.
22. A filter, which comprises the filter material of claim 16.
23. A filter element, which comprises the filter material of claim
16.
24. A smoking article, which comprises the filter material of claim
16.
Description
FIELD
[0001] The present invention relates to filter materials for use in
smoking articles. The invention also relates to filters or filter
elements comprising the filter materials, smoking articles
comprising the same, and use of the filter materials in smoke
filtration.
BACKGROUND
[0002] A wide variety of fibrous materials have been suggested as
filters for cigarette smoke. Cellulose acetate tow is the most
commonly used filter material. However, this filter material can be
relatively costly to manufacture and/or slow to degrade.
SUMMARY
[0003] According to a first aspect of the present invention, a
filter material for inclusion in a smoking article is provided,
said filter material comprising a base material comprising or made
from fibres having a first diameter or mean diameter, and fine
fibres having a diameter or mean diameter which is smaller than the
first diameter, wherein the filter material comprises more than 10%
by weight and/or by volume fine fibres.
[0004] According to a second aspect, a filter material for
inclusion in a smoking article is provided, said filter material
comprising a base material comprising or made from fibres having a
first diameter or mean diameter, and fine fibres having a diameter
or mean diameter which is smaller than the fibres of the base
material, wherein the diameter or mean diameter of the fine fibres
is between about 1.0 .mu.m and about 1.5 .mu.m.
[0005] In some embodiments of the aspects of the invention, the
fine fibres comprise cellulose acetate and/or derivatives thereof,
polylactic acid (PLA), polybutylene succinate (PBS), polyvinyl
alcohol (PVOH), polybutylene adipate terephthalate (PBAT) or
polyglycolic acid (PGA), chitosan, polyhydroxybutyrate (PHB),
polyethylene oxide (PEO), gelatine, or any combination thereof.
[0006] In some embodiments, the fine fibres consist essentially of
cellulose acetate and/or derivatives thereof.
[0007] In some embodiments, the fine fibres are produced by
centrifuge spinning or by dry spinning.
[0008] In some embodiments, the base material consists essentially
of a biodegradable material.
[0009] In some embodiments, the base material comprises or consists
essentially of polylactic acid, polyvinyl alcohol, cellulose,
cellulose acetate, or any combination thereof.
[0010] In some embodiments, the base material comprises or consists
essentially of cellulose acetate.
[0011] In some embodiments, the base material is in the form of
tow.
[0012] In some embodiments, the base material is in the form of a
non-woven web.
[0013] In some embodiments, the fine fibres are on the surface of
the base material.
[0014] According to a third aspect, filters and filter elements are
provided, comprising the filter material according to the first or
second aspects.
[0015] According to a fourth aspect, smoking articles are provided,
comprising the filter or filter elements according to the third
aspect.
[0016] According to a fifth aspect, use of the filter material of
the first or second aspects in the filtration of tobacco smoke is
provided.
BRIEF DESCRIPTION OF THE FIGURES
[0017] In order that aspects of the invention may be more fully
understood, embodiments thereof are described, by way of
illustrative example, with reference to the accompanying drawings
in which:
[0018] FIG. 1 is a schematic side view of a smoking article
including a filter according to some embodiments;
[0019] FIG. 2 is a schematic side view of a smoking article
including a filter according to some embodiments;
[0020] FIG. 3 is a schematic side view of a smoking article
including a filter according to some embodiments;
[0021] FIG. 4, 6-10 are bar charts showing the filtration
efficiency of filter materials described herein according to some
embodiments; and
[0022] FIG. 5 is a graph showing how increasing the weight content
of fine cellulose acetate fibres increases the filtration
efficiency.
DETAILED DESCRIPTION
[0023] The present invention relates to a filter material, the
filter material comprising fine fibres. As used herein, the term
"fine fibre" includes fibres with a diameter of up to about 10
.mu.m, or having a diameter of between about 0.5 .mu.m and about 10
.mu.m. In some embodiments, fine fibres are fibres with a diameter
of between about 0.7 .mu.m and about 1.5 .mu.m, optionally with a
diameter of between about 0.85 .mu.m and about 1.4 .mu.m, between
about 1.0 .mu.m and about 1.5 .mu.m and/or between about 1.0 .mu.m
and about 1.3 .mu.m. In other embodiments, fine fibres are fibres
having a diameter of between about 3 .mu.m and about 5 .mu.m, or of
between about 1.5 .mu.m and about 3 .mu.m. In yet further
embodiments, the fine fibres are fibres having a diameter of
between about 7 .mu.m and about 10 .mu.m.
[0024] In some embodiments, including, for instance, where the fine
fibres have a diameter of no more than 1.5 .mu.m, the filter
material may comprise at least about 1%, at least about 2%, at
least about 3%, at least about 4%, at least about 5%, at least
about 6%, at least about 7%, at least about 8%, at least about 9%,
at least about 10%, at least about 11%, at least about 12%, at
least about 13%, at least about 14%, at least about 15%, at least
about 16%, at least about 17%, at least about 18%, at least about
19%, at least about 20%, at least about 25%, at least about 30%, at
least about 35%, at least about 40%, at least about 45%, or at
least about 50% by weight fine fibres.
[0025] Alternatively or in addition, the filter material may
comprise more than about 1%, more than about 2%, more than about
3%, more than about 4%, more than about 5%, more than about 6%,
more than about 7%, more than about 8%, more than about 9%, more
than about 10%, more than about 11%, more than about 12%, more than
about 13%, more than about 14%, more than about 15% and/or more
than about 16% by weight fine fibres, for example, where the fine
fibres have a diameter of no more than 1.5 .mu.m.
[0026] Alternatively or in addition, the filter material may
comprise less than about 100%, less than about 95%, less than about
90%, less than about 85%, less than about 80%, less than about 75%,
less than about 70%, less than about 65%, less than about 60%, less
than about 55% and/or less than about 50% by weight fine
fibres.
[0027] In some embodiments where the fine fibres have a diameter of
between about 3 .mu.m and about 10 .mu.m, the filter material may
comprise up to 100% fine fibres. In some of these embodiments, the
fine fibres may have a diameter of between about 3 .mu.m and about
5 .mu.m, of between about 5 .mu.m and about 7 .mu.m, or the fine
fibres may have a diameter of between about 7 .mu.m and about 10
.mu.m.
[0028] In some embodiments where the fine fibres have a diameter of
less than about 1.5 .mu.m, the filter material may comprise up to
about 30% or up to about 40% by weight fine fibres, and at least
about 1% by weight.
[0029] The fine fibres may have a high surface area to volume
ratio. The fine fibres may have an extremely high surface area to
volume ratio.
[0030] The fine fibres may have any suitable cross-sectional shape.
In some embodiments, the fine fibres may have a circular or
substantially circular cross-section. In some embodiments, the fine
fibres may have a trilobal, pentalobal or elongated cross-sectional
shape, or any other shape which increases the surface to
cross-sectional area ratio.
[0031] In some embodiments, the filter material may comprise at
least about 1%, at least about 2%, at least about 3%, at least
about 4%, at least about 5%, at least about 6%, at least about 7%,
at least about 8%, at least about 9%, at least about 10%, at least
about 11%, at least about 12%, at least about 13%, at least about
14%, at least about 15%, at least about 16%, at least about 17%, at
least about 18%, at least about 19%, at least about 20%, at least
about 25%, at least about 30%, at least about 35%, at least about
40%, at least about 45% or at least about 50% by volume fine
fibres.
[0032] Alternatively or in addition, the filter material may
comprise less than about 100%, less than about 95%, less than about
90%, less than about 8 5%, less than about 80%, less than about
75%, less than about 70%, less than about 65%, less than about 60%,
less than about 55% and/or less than about 50% by volume fine
fibres.
[0033] In some embodiments, the filter material may comprise at
least about 15%, at least about 20%, at least about 25%, at least
about 30%, at least about 40%, at least about 45%, at least about
50%, at least about 55%, at least about 60%, at least about 65%, at
least about 70%, at least about 75%, at least about 80%, at least
about 85%, at least about 90% or at least about 95% by surface area
fine fibres.
[0034] Alternatively or in addition, the filter material may
comprise less than about 100%, less than about 95%, less than about
90%, less than about 85%, less than about 80%, less than about 75%,
less than about 70%, less than about 65%, less than about 60%, less
than about 55% or less than about 50% by surface area fine
fibres.
[0035] The filter material may have an acceptable and/or desirable
filtration efficiency. The filter material may have an acceptable
and/or desirable filtration efficiency for the filtration of
gaseous material, such as tobacco smoke. In some embodiments, an
acceptable filtration efficiency for the filtration of tobacco
smoke may be the removal of at least about 15%, at least about 20%,
at least about 25%, at least about 30%, at least about 35%, at
least about 40%, at least about 45%, or at least about 50%
nicotine-free dry particulate matter (NFDPM). In some embodiments,
an acceptable filtration efficiency for the filtration of tobacco
smoke may be the removal of at least about 15%, at least about 20%,
at least about 25%, at least about 30%, at least about 35%, at
least about 40%, at least about 45%, or at least about 50%
nicotine.
[0036] The filter material may have an acceptable and/or desirable
pressure drop. The fine fibres may provide an acceptable and/or
desirable pressure drop when the filter material is in use, for
example when it has been incorporated into a smoking article. In
some embodiments, filter material comprising more than 10% by
weight fine fibres may have an acceptable and/or desirable pressure
drop. In some embodiments, an acceptable and/or desirable pressure
drop may be between about 60 and about 140 mmWG, between about 80
and about 140 mmWG, between about 100 and about 140 mmWG, between
about 110 and about 140 mmWG, between about 120 and about 140 mmWG,
or between about 120 and about 135 mmWG.
[0037] In some embodiments, the diameter of the fine fibres
contributes to and/or results in an acceptable and/or desirable
pressure drop when the filter material is incorporated into a
smoking article. In some embodiments, filter material comprising
fine fibres with a diameter of between about 0.7 .mu.m and about
1.5 .mu.m, optionally between about 1.0 .mu.m and about 1.5 .mu.m,
may have an acceptable and/or desirable pressure drop.
[0038] In some embodiments, the filter material has an acceptable
and/or desirable filtration efficiency and an acceptable and/or
desirable pressure drop when in use, for example when the filter
material is incorporated into a smoking article.
[0039] In some embodiments, the fine fibres may have a sufficiently
large diameter so that they do not dissolve when in use, for
example when filtering tobacco smoke.
[0040] In some embodiments, the fine fibres may comprise cellulose
acetate and/or derivatives thereof, polylactic acid (PLA),
polybutylene succinate (PBS), polyvinyl alcohol (PVOH),
polybutylene adipate terephthalate (PBAT), polyglycolic acid (PGA),
chitosan, polyhydroxybutyrate (PHB), polyethylene oxide (PEO),
gelatine, or any combination thereof.
[0041] In some embodiments, the fine fibres may consist essentially
of, or may consist of cellulose acetate and/or derivatives
thereof.
[0042] In some embodiments, the fine fibres may comprise between
about 50% and about 100% cellulose acetate. The fine fibres of the
filter material may comprise about 20%, about 25%, about 30%, about
35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 6
5%, about 70%, about 75%, about 80%, about 85%, about 90%, about
95%, about 99% or about 100% cellulose acetate. In some
embodiments, the fine fibres of the filter material consist of 100%
cellulose acetate.
[0043] In some embodiments, the inclusion of cellulose acetate in
the fine fibres may be advantageous as cellulose acetate is known
to contribute to the selective removal of semi-volatile compounds
and/or phenolic compounds. Furthermore, cellulose acetate is a
known filter material and so the taste of the smoke will be
generally consistent with that produced by cigarettes with
conventional cellulose acetate filters when filter material
including cellulose acetate fine fibres is used for the filtration
of tobacco smoke.
[0044] The fine fibres may be produced by any method known in the
art. In some embodiments, the fine fibres are produced by
centrifuge spinning. Centrifuge spinning is a known technology, in
which a high performance centrifuge is installed in a spraying
chamber. In some embodiments, fine fibres produced by the
centrifuge cover and/or coat a substrate that is placed in the
spraying chamber. In some embodiments, the centrifuge spinning
technology has a higher productivity than other processes using
electrostatic processing.
[0045] In some embodiments, the fine fibres are prepared by a dry
spinning method as described in patent DE 2806030 (Deutsche
Institute fuer Textil- and Faserforschung Stuttgart). In dry
spinning a polymer solution is spun into a gaseous environment
where the solvent is evaporated and the polymer is forming fibres
due to external forces like gravity, mechanical drawing or air
drag, the latter being used in DE 2806030. A high speed air stream
takes the polymer solution directly at the nozzle tip, evaporates
the solvent and draws the fibres. Finally the fibres are collected
on a rod or a forming web.
[0046] In some embodiments, the fine fibres are not prepared by
electrostatic spinning (electrospinning) or by electrostatic
spraying (electrospraying).
[0047] The fine fibres may be in any suitable shape or
conformation. For example, the fine fibres may be in the form of a
thread, a floc, a tow (filter bundle), a web and/or a sheet. The
fine fibres may be in non-woven or woven form. In some embodiments,
the fine fibres are in non-woven web form. Non-woven fabrics,
sheets and the like are referred to herein as non-woven webs.
[0048] In embodiments in which the fine fibres are in the form of a
web (i.e. a light, non-woven material), the web may have a density
of at least 1 gsm, optionally at least 2 gsm. In some embodiments
in which the fine fibres are in the form of a web, the web may have
a density of between about 1 gsm and 20 gsm, optionally between
about 3 gsm and 15 gsm.
[0049] The fine fibres may be of any suitable length. In some
embodiments, the fine fibres may be referred to as being "endless"
or continuous (meaning that the fibres are long and their length
may be difficult to readily determine, especially, for example, in
a non-woven format). In some embodiments, each fine fibre may have
a length that is at least 1000 times the diameter of the fine
fibre. In some embodiments in which the filter material is placed
in a filter or filter element of a smoking article, the length of
the fine fibres may be at least as long as the width and/or length
of the filter or filter element.
[0050] In some embodiments, the fine fibres may be sufficiently
strong to withstand pressures exerted on the fine fibres during
use. For example, in embodiments in which the filter material is
incorporated into a smoking article, the fine fibres may be
sufficiently strong to withstand pressures exerted on the filter
material on smoking. In some embodiments in which the filter
material is incorporated into a smoking article, the fine fibres
are sufficiently strong so that they do not snap during
smoking.
[0051] The filter material may also include a base material. This
may comprise or be formed from fibres with a diameter or mean
diameter greater than the fine fibres. The base material may
comprise or be formed from fibres with a diameter or mean diameter
of between about 10 nm and about 50 .mu.m, optionally between about
10 .mu.m and about 30 .mu.m. In some embodiments, the base material
comprises fibres with a diameter or mean diameter of about 20
.mu.m.
[0052] A filter material comprising fine fibres and a base material
comprising or made from fibres with a greater diameter or mean
diameter than the fine fibres may be advantageous for maintaining
large pores to achieve a low pressure drop and/or a stable filter
material when the filter material is incorporated into a smoking
article.
[0053] In some embodiments, the base material and the fine fibres
consist essentially of or consist of the same material. For
example, the base material and the fine fibres may comprise,
consist essentially of, or consist of cellulose acetate and/or
derivatives thereof.
[0054] Alternatively, the material of the base material may be
different from the material of the fine fibres. The combination of
the smaller and larger diameter fibres of different materials may
give the filter material desirable properties. Such desirable
properties may include strength, good processability, efficient
filtration, affordability, biodegradability and/or
sustainability.
[0055] In some embodiments in which the fine fibres consist
essentially of or consist of cellulose acetate, the base material
comprises, consists essentially of, or consists of a material other
than cellulose acetate. The inclusion of base material that is made
from a material other than cellulose acetate may make the filter
material more affordable to manufacture.
[0056] The base material may advantageously comprise a relatively
cheap, degradable and/or sustainable material, which has the effect
that the filter material is more cost effective, degrades quicker
and/or is more sustainable than conventional filter material,
whilst also having good adsorption characteristics.
[0057] In some embodiments, the base material consists essentially
of or consists of a biodegradable material. In some embodiments,
the base material comprises, consists essentially of, or consists
of polylactide (PLA), polyvinyl alcohol (PVOH) and/or
cellulose.
[0058] Alternatively or in addition, the base material may
comprise, consist essentially of, or consist of cellulose acetate
fibres. The cellulose acetate fibres may have been produced by dry
spinning.
[0059] The base material may be in any suitable conformation. For
example, the base material may be in the form of a filament, a
floc, a tow (filter bundle), a web and/or a sheet structure. The
base material may be in non-woven or woven form.
[0060] In some embodiments, the base material may be in the form of
paper, optionally in the form of from about 20 to about 50 gsm
paper, or from about 30 to about 35 gsm paper.
[0061] In some embodiments, the fine fibres and the base material
are in close proximity. For example, the fine fibres may be
arranged on the surface of and/or within the base material
structure. In some alternative embodiments, the fine fibres and the
base material are physically separate and/or not interlinked or
intertwined.
[0062] In some embodiments, the base material is in non-woven web
form, optionally in paper form. This may offer advantages during
the manufacture of the filter material, for example by allowing the
application of the fine fibres to the surface of the web as part of
the manufacturing process of the filter material. Furthermore, the
resulting filter material may have advantageous or desirable
properties, such as increased degradability in comparison with
conventional filter material.
[0063] The base material may be produced by any method known in the
art and/or may be available commercially.
[0064] The filter material may include one or more additives. In
some embodiments, the one or more additives may affect the
adsorption characteristics of the filter material. For example, the
one or more additives may improve filtration selectivity, to
phenols for instance.
[0065] In some embodiments, the one or more additives may affect
the physical properties of the filter material. For example, the
one or more additives may improve filter hardness, depending on the
percentage weight of fine fibres in the filter material.
[0066] In some embodiments, the one or more additives may be
triacetin (TA), polyethylene glycol (PEG) and/or triethyl citrate
(TEC).
[0067] In an embodiment, the filter material comprises fine fibres
with a diameter or mean diameter of about 1 .mu.m, a base material
comprising or formed of cellulose or PVOH fibres, and an additive
such as triacetin. The resulting filter material may be
biodegradable or partially biodegradable.
[0068] The filter material may be incorporated into a filter or
filter element.
[0069] The skilled person will be aware of a suitable filter
structure. In some embodiments, the filter has one section or
compartment. The filter may be a mono filter. Alternatively, the
filter may comprise a plurality of sections, filter elements or
compartments. The filter may be a dual filter.
[0070] In some embodiments in which the fine fibres and the base
material are physically separate, one population of fibres is in
one section or area of the filter and the other population of
fibres is in another section or area of the filter.
[0071] In some embodiments, the fine fibres are positioned adjacent
to the base material. In some embodiments, the fine fibres may be
positioned between at least two segments of base material. In some
embodiments, the fine fibres are surrounded by the base material,
for example in embodiments in which the fine fibres are in the form
of a thread.
[0072] In some embodiments, the fine fibres are in the form of a
disc, which is inserted into the filter. The disc may have
substantially the same circumference as the filter, so that when
the disc is placed in the filter it will cover the entire area of
the filter when seen in transverse cross-section. This arrangement
offers the advantage that all of the substances flowing through the
filter will or are likely to encounter the disc. In some
embodiments, the disc also comprises the base material.
Alternatively or in addition, the base material may be separate
from the disc.
[0073] In some embodiments, the fine fibres are in the form of a
web material that is rolled up, to give a spiral-like conformation
when viewed in transverse cross-section, which is inserted into the
filter. In some embodiments, the web material also comprises the
base material. Alternatively or in addition, the base material may
be separate from the web material. In some embodiments, the web
material is formed into a filter or filter element using machinery
currently used for non-woven web or sheet filter manufacture.
[0074] Filter rods may be manufactured to a target length of 144 mm
and a target circumference of 24.3 mm, using a paper filter machine
(KDF2-Decoufle CU20). When incorporated into a filter or filter
element, the filter material may confer desirable physical
properties. For example, pressure drop across the filter or filter
element may be between 60 and 140 mmWG, which would be a desirable
pressure drop when the filter or filter element is incorporated
into a smoking article.
[0075] In some embodiments, the filter or filter element may have a
weight of between about 120 and about 250 mg.
[0076] The filter material may be incorporated into a smoking
article, or a part thereof. In some embodiments, a filter or filter
element containing the filter material is incorporated into a
smoking article. The filter material, filter or filter element may
be incorporated into a smoking article by any method known in the
art.
[0077] 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. In addition, in some embodiments, the term "smoking
article", as used herein, further encompasses aerosol generation
devices, such as e-cigarettes and other nicotine inhalers, as well
as inhalation devices such as so-called "heat-not-burn" devices in
which tobacco is heated but not combusted.
[0078] Referring to FIG. 1, a smoking article 1 according to an
embodiment of the invention comprises a filter 2 and a cylindrical
rod of smokeable material 3, such as tobacco, aligned with the
filter 2 such that one end of the smokeable material rod 3 abuts
the end of the filter 2. The filter 2 is wrapped in a plug wrap
(not shown) and the smokeable material rod 3 is joined to the
filter 2 by tipping paper in a conventional manner. The filter 2 is
substantially cylindrical and has a mouth end 4 and a smokeable
material end 5. The filter 2 comprises filter material 6 as
described herein.
[0079] Referring to FIGS. 2 and 3, a smoking article 1 according to
embodiments of the invention are shown. The smoking article 1 of
FIG. 2 contains one disc 7 comprising fine fibres, which is
positioned centrally in the filter 2. The smoking article 1 of FIG.
3 contains two discs 7 comprising fine fibres, which are placed at
approximately equal intervals along the filter 2. The two discs 7
are placed at the third and two third positions in the filter 2.
The filter material 6 is as described herein.
[0080] 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 filter materials. 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.
Example 1
[0081] Non-woven webs of different densities, namely 5 gsm, to gsm
and 15 gsm cellulose acetate fine fibres were produced by
centrifuge spinning, using acetic acid and/or acetone as a solvent.
The web was dried in a vacuum oven for a period of time suitable to
remove residual solvent. The fine fibres were formed into discs and
a disc was manually inserted into a cellulose acetate tow filter of
a cigarette. The disc was positioned centrally in the filter, as
illustrated in FIG. 2. The characteristics of the filters are
provided in Table 1.
TABLE-US-00001 TABLE 1 Weight of Median fine % by Pressure fine
fibres fibre diameter weight drop Filter material (mg)* (.mu.m)
fine fibres (mmWG) Cellulose acetate 0 0 0 120 tow (Bar 1 in FIG.
4) Cellulose acetate 0.23 1.3 0.22 124 tow + 5 gsm fine fibre web
(Bar 2 in FIG. 4) Cellulose acetate 0.47 1.4 0.44 130 tow + 10 gsm
fine fibre web (Bar 3 in FIG. 4) Cellulose acetate 0.70 1.3 0.66
135 tow + 15 gsm fine fibre web (Bar 4 in FIG. 4) *Calculated
approximately based on the basis weight of the fine fibre CA web
and the circumference of the cigarette filter control
[0082] The cigarettes with these filter variants were smoked
according to ISO smoking regime (35 ml puff volume with a 2 second
duration at 60 second intervals) with the ventilation zone blocked
and the filtration efficiency was measured in terms of the
filtration of nicotine-free dry particulate matter (NFDPM),
nicotine and water using the analytical procedure described in C.
Liu et al., Food Chem. Toxicol., 2011, 49(9), 1904 and in P.
Branton et al., Chemistry Central Journal (2011), 5, 15.
[0083] The filtration efficiency of the filter materials is shown
in FIG. 4. The filtration efficiency was calculated using the
following equation, where FE is the filtration efficiency and SY is
the smoke yield:
FE=100.times.(SY.sub.no filter-SY.sub.filter)/SY.sub.no filter
[0084] The results obtained show that the filters containing fine
fibres have a greater filtration efficiency than the control
filters, while at the same time having an acceptable pressure drop.
The filtration efficiency of the different analytes increases with
the gsm of the fine fibre web used in the filter.
[0085] The filtration efficiency for NFDPM, nicotine and water of
filters including cellulose acetate fine fibre web were then
plotted against the weight of the fine cellulose acetate included
and the results are shown in FIG. 5. The graph shows that the
filtration efficiency increases as the weight of fine cellulose
acetate fibre increases. Once again, the weight of fine fibres is
approximated based on the basis weight of the fine fibre CA web and
the circumference of the cigarette filter control.
Example 2
[0086] The experiment of Example 1 was carried out with fine fibre
webs having different densities (gsm), namely 5 gsm and 15 gsm
cellulose acetate fine fibres. In addition, the fine fibres used
had a smaller diameter compared to the fine fibres used in Example
1. The characteristics of the filters are provided in Table 2.
TABLE-US-00002 TABLE 2 Median fine fibre Pressure drop Filter
material diameter (.mu.m) (mmWG) Cellulose acetate tow 0 119 (Bar 1
in FIG. 6) Cellulose acetate tow + 5 0.76 130 gsm fine fibre web
(Bar 2 in FIG. 6) Cellulose acetate tow + 0.76 158 15 gsm fine
fibre web (Bar 3 in FIG. 6)
[0087] The cigarettes with these filter variants were smoked
according to ISO smoking regime with the ventilation zone blocked
and the filtration efficiency was measured.
[0088] The filtration efficiency of the filter materials is shown
in FIG. 6. The results obtained confirm that the filters containing
fine fibres exhibit greater filtration efficiency than the control
filters, while at the same time having an acceptable pressure drop.
The filtration efficiency of the different analytes again increases
with the gsm of the fine fibre web used in the filter. Furthermore,
the results of Examples 1 and 2 indicate that the filtration
efficiency is increased with a reduction in the diameter of the
fine fibres.
Example 3
[0089] The experiment of Example 1 was then carried out with
further fine fibre webs having different densities (gsm), namely 5
gsm, 7.5 gsm and 12.5 gsm and 15 gsm cellulose acetate fine fibres
of smaller diameter than in Example 1. Once again, the cigarettes
with these filter variants were smoked according to ISO smoking
regime with the ventilation zone blocked.
[0090] The filtration efficiency of the filter materials is shown
in FIG. 7 and the characteristics of the filters were as
follows:
Bar 1--Cellulose acetate tow (control) Bar 2--Cellulose acetate
tow+5 gsm fine cellulose acetate fibre web Bar 3--Cellulose acetate
tow+7.5 gsm fine cellulose acetate fibre web Bar 4--Cellulose
acetate tow+12.5 gsm fine cellulose acetate fibre web Bar
5--Cellulose acetate tow+15 gsm fine cellulose acetate fibre
web
[0091] The results obtained confirm that the filters containing
fine fibres have greater filtration efficiency than the control
filters, and the filtration efficiency of the different analytes
increases with the gsm of the fine fibre web used in the filter,
even as the gsm increases to 15.
Example 4
[0092] A non-woven web of 7.6 gsm cellulose acetate fine fibres was
produced as described in Example 1. The fine fibres were formed
into discs. The discs were manually inserted into a cellulose
acetate tow filter of a cigarette. When one disc was inserted, this
was positioned centrally in the filter, as illustrated in FIG. 2.
When two discs were inserted, these were positioned in the one
third and two thirds positions in the filter, as illustrated in
FIG. 3. The characteristics of the resulting filters are provided
in Table 3.
TABLE-US-00003 TABLE 3 Median % by Weight of fine fibre weight
Pressure fine fibres diameter fine drop Filter material (mg)*
(.mu.m) fibres (mmWG) Cellulose acetate tow 0 0 0 120 (Bar 1 in
FIG. 8) Cellulose acetate tow + 0.36 1.0 0.34 127 7.6 gsm fine
fibre web (Bar 2 in FIG. 8) Cellulose acetate tow + 2 .times. 0.71
1.0 0.67 133 7.6 gsm fine fibre web (Bar 3 in FIG. 8) *Calculated
approximately based on the basis weight of the fine fibre CA web
and the circumference of the cigarette filter control.
[0093] The cigarettes with these filter variants were smoked
according to ISO smoking regime (35 ml puff volume with a 2 second
duration at 60 second intervals) with the ventilation zone blocked
and the filtration efficiency was measured in terms of the
filtration of nicotine-free dry particulate matter (NFDPM),
nicotine and water, using the analytic methods mentioned above in
connection with Example 1.
[0094] The results of the analyses are shown in FIG. 8. The results
obtained show that the filters containing two discs of 7.6 gsm
cellulose acetate fine fibre web have a greater filtration
efficiency than the filters containing one disc of 7.6 gsm
cellulose acetate fine fibre web, and that both types of
disc-containing filters have a greater filtration efficiency than
the control filters.
Example 5
[0095] The experiment of Example 4 was then repeated with filters
including one or two discs of 7.5 gsm cellulose acetate fine fibre
web, the fine fibres having a median diameter of 0.9 .mu.m. A
summary of the characteristics of the resulting filters is provided
in Table 4.
TABLE-US-00004 TABLE 4 Pressure drop Filter material (mmWG)
Cellulose acetate tow 119 (Bar 1 in FIG. 9) Cellulose acetate tow +
136 7.5 gsm fine fibre web (Bar 2 in FIG. 9) Cellulose acetate tow
+ 167 2 .times. 7.5 gsm fine fibre web (Bar 3 in FIG. 9)
[0096] The cigarettes with these filter variants were smoked
according to ISO smoking regime (35 ml puff volume with a 2 second
duration at 60 second intervals) with the ventilation zone blocked
and the filtration efficiency was measured in terms of the
filtration of nicotine-free dry particulate matter (NFDPM),
nicotine and water.
[0097] The results are shown in FIG. 9 and they confirm that the
filters containing two discs (in this case of 7.5 gsm) of cellulose
acetate fine fibre web have a greater filtration efficiency than
the filters containing one disc, and that both types of
disc-containing to filters have a greater filtration efficiency
than the control filters.
Example 6
[0098] The influence of the diameter of the fine fibre cellulose
acetate was then investigated. Non-woven webs of 5 gsm and 15 gsm
cellulose acetate fine fibres were produced as described in Example
1. The fine fibres were formed into discs and a disc was manually
inserted into a cellulose acetate tow filter of a cigarette. The
disc was positioned centrally in the filter, as illustrated in FIG.
2. The characteristics of the filters are provided in Table 5.
TABLE-US-00005 TABLE 5 Median fine fibre diameter Pressure drop
Filter material (.mu.m) (mmWG) Cellulose acetate tow 0 119 (Bar 1
in FIG. 10) Cellulose acetate tow + 1.3 124 5 gsm fine fibre web
(Bar 2 in FIG. 10) Cellulose acetate tow + 0.76 130 5 gsm fine
fibre web (Bar 3 in FIG. 10) Cellulose acetate tow + 1.3 135 15 gsm
fine fibre web (Bar 4 in FIG. 10) Cellulose acetate tow + 0.76 158
15 gsm fine fibre web (Bar 5 in FIG. 10)
[0099] The cigarettes with these filter variants were smoked
according to ISO smoking regime (35 ml puff volume with a 2 second
duration at 60 second intervals) with the ventilation zone blocked
and the filtration efficiency was measured in terms of the
filtration of nicotine-free dry particulate matter (NFDPM),
nicotine and water.
[0100] The results are shown in FIG. 10 and they demonstrate that
the higher density fine fibre combined with the finer of the
examined fibre diameters produced the highest filtration
efficiency. This correlation was very clear for NFDPM and nicotine,
but was less pronounced for water. Indeed, for water the
combination of lower density (5 gsm) and larger diameter (1.3
.mu.m) exhibited better filtration than the lower density (5 gsm)
and smaller diameter (0.76 .mu.m). Otherwise, the smaller fine
fibre diameter produced better filtration results.
Example 7
[0101] In the previous experiments, the discs of non-woven fine
fibre web were positioned perpendicular to the smoke flow (as shown
in FIGS. 2 and 3). To determine the influence of the position of
the web, in this experiment, the hand-made cigarettes of the
following filter variants were made: [0102] conventional CA tow as
a control [0103] a disc of fine fibre CA web inserted in the middle
of a CA tow filter [0104] a disc of CA tow inserted in the middle
of a CA tow filter.
[0105] These cigarettes were smoked under the same conditions.
Smoke yields are shown in and the calculated filtration
efficiencies are given in Table 6. The results showed that the
filtration efficiency for nicotine was 44.7 and 39.4% in the
cigarettes with filters having a disc of fine fibre CA web and a
disc of CA tow in the filter respectively in comparison to the
control filter with 35.5% filtration efficiency. The same trend was
obtained for the filtration efficiency of NFDPM for these
cigarettes. These results illustrate the effect of the fibre
diameter in the filter where adding 1.8 mg of fine fibres resulted
in an increase of about 9% in the filtration efficiency of nicotine
whereas adding 5.75 mg of regular fibres led to about 4% increase
only. The increase in the pressure drop and the filtration
efficiency was even more pronounced when a disc of fine fibre CA
web was inserted into a paper filter. This could be related to the
difference in the void volumes in the CA and paper filters.
Inserting a disc of paper into the paper filter was not an easy
manual operation and led to a relatively high pressure drop and so
these cigarettes were not included in the smoke analyses tests.
[0106] The normalised phenol results showed that inserting a fine
fibre CA web into the CA filters did not increase the retention of
phenol. This suggests that the selectivity of CA for phenol
retention does not depend on the CA fibre diameter. The paper
filter results showed a significant decrease in the normalised
phenol yield once a disc of fine fibre CA web was inserted into the
filter but the yield was still relatively higher in comparison to
the normalised yield in the cigarettes with the CA filter.
TABLE-US-00006 TABLE 6 Filter Description CA tow + CA tow + paper
filter + CA tow disc of fine disc of CA paper disc of fine No
Control fibre CA tow filter fibre CA filter Plasticiser (Pz) TA TA
TA None None -- Pz Amount (%) 7.0 7.0 7.0 0.0 0.0 -- Fine fibre
CA/tow disc weight (mg) 0.0 1.80 5.75 0.0 1.80 -- Cigarette (bound)
PD (mmWG) 119 135 126 108 165 50 Puff Number 8.1 8.1 7.9 7.9 7.9
8.0 Analyte Unit CO mg/cig 12.7 12.5 13.2 12.6 12.5 12.1 Nicotine
mg/cig 0.92 0.79 0.87 0.62 0.35 1.43 Water mg/cig 2.7 2.77 2.51
1.47 0.80 5.43 NFDPM mg/cig 13.9 12.1 13.4 9.34 5.86 22.2 TPM
mg/cig 17.6 15.7 16.7 11.4 7.01 29.1 Catechol .mu.g/cig 60.8 55.0
61.4 46.4 24.9 110 Hydroquinone .mu.g/cig 57.6 53.7 61.4 40.8 20.4
103 m-Cresol .mu.g/cig 3.62 3.31 3.64 4.44 2.17 11.4 o-Cresol
.mu.g/cig 4.77 4.26 4.73 6.19 2.92 16.2 p-Cresol .mu.g/cig 10.1
9.10 9.97 12.4 6.15 32.0 Phenol .mu.g/cig 19.8 17.5 20.1 30.3 14.4
83.5 Resorcinol .mu.g/cig NQ NQ NQ NQ NQ 2.4 Filtration efficiency
(%) NFDPM 37.3 45.3 39.8 57.9 73.6 Nicotine 35.5 44.7 39.4 56.6
75.5 Water 49.9 49.0 53.8 72.9 85.3 Catechol 44.9 50.1 44.3 57.9
77.4 Hydroquinone 44.2 48.0 40.6 60.5 80.2 m-Cresol 68.2 71.0 68.1
61.0 80.9 o-Cresol 70.7 73.8 70.9 61.9 82.0 p-Cresol 68.5 71.6 68.8
61.1 80.8 Phenol 76.2 79.1 75.9 63.6 82.7 Normalised yield
(.mu.g/mg NFDPM) Catechol 4.4 4.5 4.6 5.0 4.2 5.0 Hydroquinone 4.1
4.4 4.6 4.4 3.5 4.7 m-Cresol 0.3 0.3 0.3 0.5 0.4 0.5 o-Cresol 0.3
0.4 0.4 0.7 0.5 0.7 p-Cresol 0.7 0.8 0.7 1.3 1.0 1.4 Phenol 1.4 1.4
1.5 3.2 2.5 3.8
Example 8
[0107] The effect of the fine CA fibres in the cigarette filters
was also investigated using machine-made filters including a fine
fibre CA web deposited on paper as a carrier.
[0108] Three samples of different fine fibre CA web basis weights
were used, namely 3, 6 and 9 gsm, all with a fibre diameter of 1.3
.mu.m. Filter rods were made from these samples and the
manufactured filter rods had the characteristics set out in Table
7. Due to the limited supply of the fine fibre CA web deposited on
paper, it was not possible to manufacture filter rods with similar
pressure drops. Because of the difference in the pressure drops of
the test sample filter rods controls of different pressure drops
were manufactured to match the pressure drop of the test
samples.
[0109] From the filter rods characteristics (Table 7) it can be
seen that the weight of the filter rods made with the fine fibre CA
web/paper is lower than that of the controls made from just paper
at similar pressure drops. Additionally, increasing the basis
weight of the fine fibre CA web resulted in a need to decrease the
web width to make the filter rods with a similar pressure drop.
TABLE-US-00007 TABLE 7 Web Fine fibre Fine fibre Filter rod Filter
rod Filter rod width CA basis weight CA web/paper weight
circumference (bound) PD Filter (mm) (gsm) (%) (mg) (mm) (mmWG) CA
3 gsm 206 3 9/91 1171 24.5 499 CA 6 gsm 195 6 17/83 1168 24.4 404
CA 9 gsm 188 9 26/74 1209 24.4 423 Paper (1) 256 -- 0/100 1282 24.5
343 Paper (3) 272 -- 0/100 1396 24.5 455 Paper (4) 280 -- 0/100
1429 24.4 564 Paper (6) 266 -- 0/100 1360 24.4 427
[0110] The smoke chemistry analyses of the manufactured cigarettes
were carried out under the ISO smoking regime with the ventilation
zone blocked and the results are provided in Tables 8 and 9.
TABLE-US-00008 TABLE 8 Filter CA 3 gsm CA 6 gsm CA 9 gsm Web width
(mm) 206 195 188 Fine fibre CA basis weight 3 6 9 (gsm) Fine fibre
CA web/paper 9/91 17/83 26/74 composition (%) Plasticiser None None
None Plasticiser Loading (%) 0.0 0.0 0.0 Filter Weight (g) 0.22
0.26 0.23 Bound filter PD (mmWG) 92 109 100 Analyte Unit CO mg/cig
13.7 13.7 12.9 NFDPM mg/cig 8.54 5.44 5.27 Nicotine mg/cig 0.50
0.30 0.30 Water mg/cig 1.77 0.79 0.73 TPM mg/cig Catechol .mu.g/cig
32.0 21.2 16.8 Hydroquinone .mu.g/cig 28.2 17.5 15.4 m-Cresol
.mu.g/cig 2.67 1.76 1.27 o-Cresol .mu.g/cig 3.68 2.06 1.66 p-Cresol
.mu.g/cig 7.58 5.26 3.59 Phenol .mu.g/cig 17.7 10.5 7.79 Resorcinol
.mu.g/cig NQ NQ NQ Filtration efficiency (%) NFDPM 64.7 77.5 78.2
Nicotine 69.4 81.7 81.5 Water 72.6 87.7 88.8 Catechol 67.0 78.1
82.7 Hydroquinone 66.1 78.9 81.5 m-Cresol 73.2 82.3 87.3 o-Cresol
73.9 85.4 88.2 p-Cresol 72.7 81.0 87.1 Phenol 75.8 85.7 89.4
Normalised yield (.mu.g/mg NFDPM) Catechol 3.75 3.90 3.19
Hydroquinone 3.30 3.22 2.92 m-Cresol 0.31 0.32 0.24 o-Cresol 0.43
0.38 0.31 p-Cresol 0.89 0.97 0.68 Phenol 2.07 1.93 1.48
[0111] The smoke yields and the calculated filtration efficiencies
for NFDPM, nicotine and phenolic compounds of the cigarettes with
fine fibre CA/paper filters provided in Table 8 show that at
similar filter weight and pressure drop the filtration efficiency
increases with increasing the content of the fine fibre CA in the
filter.
[0112] The comparison of the filtration efficiency of the
cigarettes with fine fibre CA/paper filters and the control (paper)
filter at similar pressure drops shows that increasing the content
of fine fibre CA increases the filtration efficiency (Tables 8 and
9). This was also seen in the case of the hand-made cigarettes
reported in the previous Examples.
[0113] The normalised phenol results in Table 8 show that
increasing the weight of the fine fibre CA in the filter results in
the decrease of the normalised phenol yields.
TABLE-US-00009 TABLE 9 Filter CA No P1 P3 P4 P6 Control Filter
Paper width (mm) 256 272 280 266 -- -- Plasticiser None None None
None TA -- Plasticiser Loading (%) 0.0 0.0 0.0 0.0 10.1 -- Filter
Weight (g) 0.24 0.26 0.26 0.25 0.16 -- Bound filter PD (mmWG) 70 87
110 80 74 -- Analyte Unit CO mg/cig 13.1 13.7 12.6 12.6 13.3 13.2
NFDPM mg/cig 9.69 9.47 7.55 9.14 14.3 24.2 Nicotine mg/cig 0.59
0.57 0.46 0.56 0.99 1.64 Water mg/cig 1.61 1.61 0.97 1.43 3.01 6.46
TPM mg/cig Catechol .mu.g/cig 43.9 34.8 34.9 36.6 53.3 97.0
Hydroquinone .mu.g/cig 37.6 30.9 31.0 32.8 51.0 83.0 m-Cresol
.mu.g/cig 4.17 3.14 3.19 3.47 3.08 9.96 o-Cresol .mu.g/cig 5.18
4.44 4.41 4.85 3.99 14.1 p-Cresol .mu.g/cig 12.4 8.75 8.85 9.41
8.52 27.8 Phenol .mu.g/cig 27.2 21.5 21.4 22.9 16.8 73.1 Resorcinol
.mu.g/cig NQ NQ NQ NQ NQ 2.13 Filtration efficiency (%) NFDPM 60.0
60.9 68.8 62.2 40.9 Nicotine 63.8 65.2 72.1 65.9 39.7 Water 75.1
75.1 85.0 77.9 53.4 Catechol 54.8 64.2 64.0 62.3 45.1 Hydroquinone
54.7 62.7 62.6 60.4 38.6 m-Cresol 58.1 68.5 68.0 65.2 69.0 o-Cresol
63.3 68.5 68.7 65.6 71.7 p-Cresol 55.4 68.5 68.1 66.1 69.3 Phenol
62.8 70.6 70.7 68.7 77.0 Normalised yield (.mu.g/mg NFDPM) Catechol
4.53 3.67 4.62 4.00 3.73 4.01 Hydroquinone 3.88 3.26 4.11 3.59 3.57
3.43 m-Cresol 0.43 0.33 0.42 0.38 0.22 0.41 o-Cresol 0.53 0.47 0.58
0.53 0.28 0.58 p-Cresol 1.28 0.92 1.17 1.03 0.60 1.15 Phenol 2.81
2.27 2.83 2.51 1.17 3.02
[0114] The results showed that, in comparison to the paper control
filter, the fine fibre CA web/paper filter resulted in a reduced
filter weight at a similar pressure drop, increased filtration
efficiency at a similar pressure drop and increased filtration
selectivity for phenol.
[0115] The results obtained from combining fine fibre cellulose
acetate with paper indicate that this type of filter material can
be considered as an alternative to conventional cellulose acetate
tow, providing comparable filtration characteristic but enhanced
degradability. Such paper-based filter materials would be expected
to show significantly increased degradability in comparison with
conventional filter material.
* * * * *