Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Smoking Article
Technical Field
The present invention relates to a smoking article and a method of
manufacturing a
smoking article.
Background
Cigarettes and other combustible smoking articles produce smoke which is
inhaled by a
user. Tobacco is wrapped in a paper wrapper to form a tobacco rod and a filter
may be
/o connected to the tobacco rod. Filters can be configured to modify
properties of smoke
produced by the smoking article, for example, by adding flavourant to the
smoke
produced by the smoking article.
Summary
/5 According to embodiments of a first aspect of the invention, there is
provided a
smoking article comprising tobacco material wrapped in a paper wrapper to form
a
tobacco rod, wherein the paper wrapper has a diffusivity of between about 0.1
cm/s and
0.5 cm/s and a permeability of less than about 15 CU.
20 The paper wrapper may have a diffusivity of between about 0.1 cm/s and
0.3 cm/s.
The paper wrapper may have a diffusivity of between about 0.15 and about 0.25,
between about 0.15 and about 0.20, or between about 0.17 and about 0.22 CM/S.
25 The paper wrapper may have a permeability of less than about 15 CU over
at least 50%
of the surface area of the paper wrapper.
The paper wrapper may have a permeability of between about 4 and about 12 CU.
30 .. The paper wrapper may have a permeability of between about 4 and about
12 CU over
at least 90% of the surface area of the paper wrapper.
The paper wrapper may have a permeability of less than about 10 CU, or between
about
3 and about 7 CU, over at least 90% of the surface area of the paper wrapper.
The smoking article may comprise a filter.
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A pressure drop across the filter may be between about 40 mm WG and 180 mm WG.
The filter may comprise a ventilation area.
The ventilation area may provide ventilation of between 40% and 90%.
The filter may comprise filter material having a denier per filament of
between 2.5 and
9.
The filter may comprise filter material having a total denier of between
10,000 and
32,000.
The paper wrapper may have a basis weight of between 24 and 36 g/m2.
The paper wrapper may have a basis weight of between 27 and 32 g/m2.
The paper wrapper may have a basis weight of about 28 g/m2.
The paper wrapper may have a basis weight of about 32 g/m2.
The paper wrapper may include less than 30% filler by weight of the paper
wrapper.
The paper wrapper may include between 15 and 25% filler by weight.
The filler may comprise calcium carbonate.
The paper wrapper may have an opacity of between 60% and 80%, or between 68%
and
80%.
The paper wrapper may comprise less than 4% burn additive by weight of the
paper
wrapper.
The paper wrapper may comprise about 1% burn additive by weight.
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The burn additive may be sodium citrate, potassium citrate, or a mixture of
sodium
citrate and potassium citrate.
According to embodiments of a second aspect of the invention, there is
provided a
.. method of manufacturing a smoking article, the method comprising forming a
tobacco
rod by wrapping tobacco material in a paper wrapper having a diffusivity of
between
about 0.1 cm/s and 0.5 cm/s and a permeability of less than about 15 CU.
The method may further comprise attaching a filter to said tobacco rod.
The method may further comprise providing a ventilation area for allowing
ventilation
into said filter.
The paper wrapper may have a diffusivity of between about 0.1 cm/s and 0.3
cm/s.
The paper wrapper may have a permeability of between about 4 and about 12 CU
over
at least 5o% of the surface area of the wrapper.
The paper wrapper may have a permeability of between about 4 and about 12 CU
over
at least 90% of the surface area of the wrapper.
Brief Description of the Drawings
Embodiments of the invention will now be described, by way of example only,
with
reference to accompanying drawings in which:
Figure 1 illustrates a smoking article according to an embodiment;
Figure 2 illustrates a smoking article according to a further embodiment,
having a filter
comprising a capsule;
Figure 3 illustrates a smoking article according a further embodiment, having
a filter
comprising a tubular element; and
Figure 4 illustrates a smoking article according a further embodiment, having
a filter
comprising a tubular element and adsorbent material dispersed within filter
material.
Detailed Description
The term "smoking article" as used herein is intended to refer to combustible
smoking
articles and their components such as cigarettes, cigarillos, cigars and roll-
your-own
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cigarettes (whether based on tobacco, tobacco derivatives, expanded tobacco,
reconstituted tobacco, tobacco substitutes or other smokable material).
Filters described herein can be provided to users as an integral component of
a
smoking article or as a discrete component separate from a smoking article.
When
provided separately, filter units and smoking articles can be packaged
separately, or
packaged together as a kit of parts.
Smoking articles such as cigarettes and their formats are often named
according to the
w 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 no mm to about 121 min).
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 have a circumference of from 23 to 25 mm and an overall
length of
from 75 to 91 mm.
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 about 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, such that the
tipping paper
covers the filter and overlaps the tobacco rod to connect the filter to the
tobacco rod.
Smoking articles and filters described herein can be made in, but are not
limited to, any
of the above formats.
The filter material forming the filters described herein can comprise
cellulose acetate
fibre tow. The filter material can also be formed using other materials used
to form
fibres, such as polyvinyl alcohol (PVOH), polylactic acid (PLA),
polycaprolactone (PCL),
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poly(i-4 butanediol succinate) (PBS), poly(butylene adipate-co-
terephthalate)(PBAT),
starch based materials, paper, cotton, aliphatic polyester materials and
polysaccharide
polymers or a combination thereof. The filter material may be plasticised with
a
suitable plasticiser for the filter material, such as triacetin where the
filter material is
cellulose acetate tow, or may be non-plasticised. The tow used to produce the
filter unit
or other filter component can use any suitable specification, such as fibres
having a 'Y'
shaped or other cross section, filamentary denier values between 2.5 and 15
denier per
filament, for example between 3.0 and 9.0 denier per filament and total denier
values
of 10,000 to 50,000, for example between 15,000 and 45,000.
As used herein, the terms "flavour" and "flavourant" refer to materials which,
where
local regulations permit, may be used to create a desired taste or aroma in a
product for
adult consumers. They may include extracts (e.g., liquorice, hydrangea,
Japanese white
bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint,
aniseed,
cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon,
scotch,
whiskey, spearmint, peppermint, lavender, cardamom, celery, cascarilla,
nutmeg,
sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil,
orange oil,
cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger,
anise,
coriander, coffee, or a mint oil from any species of the genus Mentha),
flavour
enhancers, bitterness receptor site blockers, sensorial receptor site
activators or
stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame
potassium,
aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose,
sorbitol, or
mannitol), and other substances or additives such as charcoal, chlorophyll,
minerals,
botanicals, or breath freshening agents. They may be imitation, synthetic or
natural
ingredients or blends thereof. They may be in any suitable form, for example,
oil,
liquid, or powder.
In the figures described herein, like reference numerals are used to
illustrate equivalent
features, articles or components.
Figure 1 is a side-on cross sectional view of a smoking article 1. The smoking
article 1,
in the present example a cigarette, has a mouth end la, arranged to be placed
in the
user's mouth when smoking, and a lit end lb, arranged to be lit when smoking.
Tobacco material 2 is wrapped in a paper wrapper 3 to form a tobacco rod.
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In some examples, the smoking article does not include a filter. In other
examples, a
filter 4 is connected to the tobacco rod, by a tipping paper 5. The filter 4
is wrapped in
a plug wrap 6. A ventilation area 7 may be provided to allow external air into
the filter
4 during use. The ventilation area may be provided as a series of perforations
which
pass through the tipping paper 5 and plug wrap 6 and into the filter 4.
The paper wrapper 3 has a diffusivity of between about 0.1 cm/s and 0.5 cm/s.
In some
examples, the paper wrapper 3 has a diffusivity of between about o.icm/s and
about
0.3 cm/s.
In some examples, the paper wrapper 3 has a diffusivity of less than about
0.30 cm/s.
In some examples, the paper wrapper 3 has a diffusivity of less than 0.25
cm/s. In
some examples, the paper wrapper 3 has a diffusivity of between 0.15 and 0.2
cm/s.
Advantageously, such levels of diffusivity have been found to be particularly
effective at
/5 providing smoking articles such as cigarettes with more consistent
delivery per puff,
and an increased number of puffs. Such smoking articles have also been found
to pass
the low ignition propensity tests known in the industry, while exhibiting
acceptable
rates of free air self-extinguishment. Free air self-extinguishment is the
property of a
smoking article to self-extinguish when held in free air (i.e. rather than
being placed on
a substrate), which is undesirable from a consumer's perspective. In some
examples,
the paper wrapper has a diffusivity of between 0.10 and 0.3 cm/s, between 0.15
and
0.25 cm/s, between 0.15 and 0.20 cm/s, or between 0.17 and 0.22 cm/s.
The paper wrapper 3 has a low permeability, in the present example a
permeability of
less than about 15 Coresta Units (CU). For instance, the paper wrapper can
have a
permeability of less than about 15 CU over at least 5o% of the surface area of
the paper
wrapper, or over at least 75% or 90% of the surface area.
In some examples, the paper wrapper 3 has a permeability of between about 4
and
about 12 CU. In some examples, the paper wrapper 3 has a permeability of
between
about 4 and about 12 CU over at least 90% of the surface area.
In some examples, the paper wrapper 3 has a permeability of less than 10
Coresta Units
(CU), or between about 3 and about 7 CU, in each case over at least 5o%, or
more
preferably 75% or 90% of the surface area of the paper wrapper.
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In use of the smoking articles described herein, the paper wrapper 3 having
the low
diffusivity and low permeability ranges as described reduces the amount of
oxygen
drawn into the tobacco rod when the smoking article is smoked, as compared to
smoking articles having paper wrappers with higher levels of diffusivity and
permeability. Reducing the amount of oxygen drawn into the tobacco rod causes
the
tobacco 2 to burn at a slower rate between puffs, and thus has the effect of
increasing
the length of time over which the tobacco rod combusts, proving a longer
smoking
experience.
/o In some examples, the entire paper wrapper 3 has the low diffusivity and
low
permeability ranges defined herein.
In some examples, the diffusivity of the paper wrapper 3 may be uniform along
the
length of the tobacco rod when the paper wrapper 3 is wrapped around the
tobacco rod.
/5 Additionally or alternatively, the diffusivity of the paper wrapper 3
may be uniform
around the entire circumference of the tobacco rod. The paper wrapper 3 may
include
some areas having higher or lower diffusivity. In some examples, at least 50%
of the
paper wrapper is provided with a low diffusivity, for example, below 0.3cm/s.
In some
examples, more than 75%, or 80% or about l00% of the wrapper is provided with
a low
20 diffusivity, for example, below 0.3cm/s or below 0.25 cm/s.
Alternatively or in
addition, at least 50% of the paper wrapper can be provided with a low
permeability, for
example, below 15 CU. In some examples, more than 80%, 90%, or about l00% of
the
wrapper is provided with a low permeability as described, for example below 15
CU.
The paper wrapper may have one or more discrete regions having low
permeability and
25 low diffusivity. In some examples, the entire paper wrapper is provided
with a uniform
low diffusivity and low permeability within the ranges described herein.
Providing the
entire paper wrapper with low diffusivity and low permeability reduces
variability in
free air self-extinguishment property of the smoking article for the duration
of smoking
compared to providing two or more discrete areas of the smoking article with
low
30 diffusivity and low permeability.
The filter 4 may be substantially cylindrical in shape. The filter 4 may be
between 6
mm and 30 mm in length, for instance between 7 mm and 20 mm. In one example,
the
filter 4 is 18 mm in length.
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The tobacco rod may also be substantially cylindrical in shape, with an
external
diameter substantially equal to the external diameter of the filter 4 if a
filter is
provided. The tobacco rod comprises a substantially cylindrical core of packed
tobacco
material 2 wrapped in the paper wrapper 3. The tobacco material 2 may comprise
a
blend of shredded tobacco, and may also include reconstituted tobacco
material. The
paper wrapper 3 extends around the circumference of the tobacco rod and
extends
along its length, to form a wrapped tobacco rod. The end faces of the tobacco
rod are
left open to allow a gaseous flow to pass axially through the rod.
In some embodiments, the tobacco rod includes tobacco having a net weight
based on
the size and type of the smoking article. For example, the tobacco weight may
be a
standard weight corresponding to a conventional smoking article of the same
size. In
some embodiments, the tobacco weight may be reduced compared to a conventional
smoking article of the same size. The tobacco weight may be selected based on
the
is desired characteristic of the smoking article. A lower tobacco weight
may be associated
with a reduction of staining of the paper wrapper. In addition, a lower
tobacco weight
may be associated with a reduction in the levels of CO and tar. However, a
lower
tobacco weight may also be associated with a reduction in puff number.
Accordingly,
the tobacco weight may be chosen according to the characteristic of the
smoking article
to be achieved.
In some examples, the smoking article may be a smoking article having a length
of
9omm and a circumference of imm. The net tobacco weight may be, for example,
510mg. In other examples, the smoking article may have a reduced tobacco
weight of
480mg. The smoking article having the reduced tobacco weight of 480mg may
include
lower levels of CO and tar, and experience lower levels of staining on the
paper
wrapper. However, the puff number of the smoking article having the reduced
tobacco
weight of 480mg may have a lower puff number when smoked by a user compared to
a
comparable smoking article having a net tobacco weight of 480mg.
In other examples, a smoking article having a length of about 9omm and a
circumference of about 2imm may include a tobacco weight of 49omg.
Alternatively
the smoking article may include a reduced tobacco weight of about 460mg.
In other examples, a smoking article having a length of about 9omm and a
circumference of about 23mm may include a tobacco weight of around 630mg.
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Alternatively, the smoking article may include a reduced tobacco weight of
about
56omg.
It will be apparent to the skilled person that the tobacco weight may be
selected based
on these characteristics of the resulting smoking article, for example by
selecting a
lower tobacco weight in order to reduce staining and CO and tar levels, or by
selecting a
higher tobacco weight to increase the number of puffs than can be obtained on
smoking.
io During use, in which the smoking article 1 is smoked by a user, air is
drawn through the
lit tobacco rod to provide smoke to the user. In embodiments including a
filter, the
smoke is also drawn through the filter to remove some particulate material
from the
smoke before it is provided to the user. In embodiments including a ventilated
filter,
during use air is drawn through the ventilation area 7 of the filter 4 in
order to dilute
is the smoke delivered to the user through the filter 4.
In some examples, the ventilation area 7 comprises perforations in the filter
tipping
paper 5 and plug wrap 6. In some examples, the ventilation area 7 comprises
embossed
regions in the filter tipping paper 5 and/or plug wrap 6. At least one of the
tipping
20 paper 5 and plug wrap 6 can alternatively be provided as a porous
material, for instance
having a porosity greater than 200 Coresta Units, allowing air into the filter
4. The
filter 4 may be vented by vent channels formed using laser or electrostatic
perforation
techniques. The ventilation area 7 can be provided into any part of the filter
4, for
instance a part at least 12 mm from the mouth end la of the smoking article.
In
25 examples having multiple filter sections or segments, the ventilation
area can, for
instance, be provided into a filter section or segment adjacent to the tobacco
rod.
In some examples, the pressure drop across the filter 4 is between 40 mm WG
and 180
mm WG. The pressure drop of the filter may be selected depending on the
desired
30 characteristics of the product. In some examples, the pressure drop
across the filter is
between 70mmWG and i8ommWG. In some examples, the pressure drop across the
filter is between 13ommWG and i8ommWG. In some examples, the pressure drop
across the filter is between 1.4.0mmWG and i8ommWG. In some examples, the
pressure drop across the filter is between 70mmWG and loommWG. In some
35 examples, the pressure drop across the filter is between 85mmWG and
wommWG.
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In some examples, filter is not provided with a ventilation area. In other
examples, the
filter is provided with a ventilation area. The ventilation area 7 of the
filter 4 may
provide between 40% and 90% ventilation when the smoking article is smoked in
use.
The ventilation area can, for instance, provide between 55% and 90%
ventilation. In
some examples, the ventilation area provides between 55% and 85% ventilation.
In
some examples, the ventilation area provides between 60% and 75% ventilation.
In
some examples, the ventilation area provides between 65% and 75% ventilation.
By changing the levels of ventilation and the pressure drop across the filter,
the levels of
/o CO and tar delivered to the user may be altered. A higher ventilation
level across the
filter results in the levels of tar and CO being reduced when using the
cigarette paper
with low diffusivity and low permeability as described herein. A higher level
of
ventilation also increases the number of puffs during smoking. However, a
lower
ventilation level across the filter reduces the likelihood of the smoking
article to self-
/5 extinguish in free air during smoking. Therefore, the ventilation level
may be selected
according to these properties of the smoking article.
In some examples, the paper wrapper surrounding the tobacco rod has a basis
weight of
between 24 and 36 g/m2. The weight of the paper is one of the factors which
may
20 influence the diffusivity of the paper. An increased weight per square
metre of the
paper increases the diffusivity of the paper. Therefore, in order to provide a
low
diffusivity for the wrapper, the weight of the paper is selected to be between
24 and 36
g/m2. In some examples, the paper surrounding the tobacco rod has a weight
between
27 and 32 g/m2. In some examples, the paper surrounding the tobacco rod has a
weight
25 of about 28 g/m2. In some examples, the paper surrounding the tobacco
rod has a
weight of about 32 g/m2. Higher weight per square metre of the paper wrapper 3
may
also provide for increased opacity of the paper wrapper. Increasing the basis
weight of
the paper together with increasing the diffusivity of the paper reduces the
level of
staining of the cigarette paper during smoking.
In some examples, the paper may comprise a filler. In some examples, the
filler content
of the paper wrapper 3 is less than 30% by weight of the paper. In some
examples, the
filler content of the paper wrapper is between 15 and 25% by weight. A lower
filler
content decreases the diffusion capacity of the paper wrapper and so may also
lead to
increased LIP (low ignition propensity) pass rates. In addition, using lower
filler
content may increase the number of puffs achievable when the smoking article
is
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smoked in use. The filler content of the paper wrapper may be above 15%. In
some
examples, the filler content of the paper wrapper may be between 21 and 22% by
weight. In some examples, the filler is calcium carbonate. However, it will be
recognised that any other suitable filler may be used. It will be recognised
that the
amount of the filler used may be selected by the skilled person in order to
achieve
desired characteristics such as, but not limited to, diffusivity, puff number,
opacity,
smoke yield and LIP pass rate.
The opacity of the paper may be affected by the particle size of the filler
used. For
example, smaller particle sizes may result in higher opacity. In some
examples, the
particle size may be between o.3vtm and 21m. The opacity may also be affected
by the
structure of the filler. For example, when calcium carbonate is used as the
filler, it may
comprise, but is not limited to, calcite crystal, precipitated calcium
carbonate, or
ground calcium carbonate.
In some examples, the paper wrapper comprises a burn additive. In some
examples,
the paper wrapper comprises less than 4% burn additive by weight. The burn
additive
decreases the likelihood that the smoking article will self-extinguish in free
air, that is,
for example, when the user is holding the smoking article between puffs.
However,
.. increasing the level of burn additive may decrease the LIP pass rate of the
smoking
article. In some examples, the paper wrapper comprises 1% burn additive by
weight.
In some examples, the burn additive is tri-potassium citrate. In some
examples, the
burn additive is tri-sodium citrate. In some examples, the burn additive
comprises tri-
sodium citrate and tri-potassium citrate. However, it will be recognised that
any
suitable burn additive may be used. The amount of burn additive may be
selected by
the skilled person in order to achieve desired characteristics such as, but
not limited to,
smoke yield and LIP pass rate.
In some examples, the filter comprises filter material having a denier per
filament of
between about 2.5 and about 9, for instance between about 3 and about 8.
In some examples, the filter comprises filter material having a total denier
of between
about 10,000 and about 32,000, for instance between about 12,000 and about
30,000.
Figure 2 illustrates a smoking article 1' according to a further embodiment,
the smoking
article 1' being the same as the smoking article 1 of Figure 1 except having a
filter 4
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comprising a capsule 8. In the present example, the filter 4 is formed from
filter
material, in the present case cellulose acetate tow treated with a
plasticiser, in the
present case triacetin. The capsule 8 is spherical and has a diameter of 3.mm,
although other shapes and sizes of capsule can be used, for instance a capsule
having a
.. diameter of about 3 mm, or between 0.5 mm and 6 mm, or between 2 mm and
5mm.
The capsule 8 is embedded within and surrounded on all sides by the filter
material of
the filter 4. The capsule 8 contains a fluid additive which modifies
properties of
mainstream smoke passing through the smoking article ii. The capsule 8 can be
manufactured and inserted into the filter 4 using existing processes and
machinery. In
io the present example, the capsule 8 contains menthol flavourant, although
other fluids
or granular additives could be contained within the capsule 8. The capsule can
be
ruptured by a consumer squeezing the filter to release the fluid additive into
the filter
material of the filter 4. The filter 4 of Figure 2 may be between 7 mm and 30
mm in
length, for instance between 7 mm and 20 mm. In one example, the filter 4 is
18 mm in
is length.
Figure 3 illustrates a smoking article 1" according a further embodiment, the
smoking
article 1" being the same as the smoking article 1 of Figure 1, except having
a filter
section 4a similar to the filter 4 of Figure 1 connected coaxially to a
tubular element 4h.
20 .. The tubular element 4h is formed from fibrous filter material in the
present example.
The fibrous filter material is, in the present example, continuous cellulose
acetate tow
plasticised with triacetin. A channel extends lengthwise through the centre of
the
tubular element 4h. The channel extending through the centre of the filter
element 4h
can be from imm to 6mm in diameter, for instance from 2MM to 5mm in diameter.
25 The tubular element 4h may be a non-wrapped element or may be wrapped in
a plug
wrap (not shown). The filter section 4a may also be non-wrapped or wrapped in
a plug
wrap (not shown), and a combining plug wrap 10 may be used to connect the
tubular
element 4h and filter section 4a. The filter section 4a may be between 6 mm
and 30
mm in length, for instance between 6 mm and 20 mm. In one example, the filter
30 section 4a is 12 mm or 18 mm in length. The hollow tubular element 4h
may be
between 6 mm and 15 mm in length, for instance between 6 mm and 12 mm or in
one
example 7 mm in length.
Figure 4 illustrates a smoking article 1" according a further embodiment, the
smoking
35 .. article 1" being the same as the smoking article 1" of Figure 3, except
having a filter
segment 4c including an adsorbent material 9 dispersed within filter material
upstream
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of the filter section 4a. A combining plug wrap 10 may be used to connect the
tubular
element 4h, filter section 4a and filter segment 4c. The adsorbent material 9
is, in the
present example, provided in the form of activated carbon particles, although
other
forms of adsorbent can be used, such as ion exchange resins. The filter
section 4c may
be between 6 mm and 20 mm in length, for instance between 6 mm and 18 mm or in
one example 12 mm in length.
In a method of manufacturing a smoking article, for instance a smoking article
as
described herein, in a first step a tobacco rod is formed by wrapping tobacco
material in
io a paper wrapper having a diffusivity of between about 0.1 cm/s and 0.5
cm/s and a
permeability of less than about 15 CU. In a second step, a filter may be
attached to the
tobacco rod. In a third step, a ventilation area may be provided for allowing
ventilation
into the filter.
In some examples of the method, the paper wrapper has a diffusivity of between
about
0.1 cm/s and 0.3 cm/s. In some examples, the paper wrapper has a permeability
of
between about 4 and about 12 CU over at least 5o% of the surface area of the
wrapper.
In some examples, the paper wrapper has a permeability of between about 4 and
about
12 CU over at least 90% of the surface area of the wrapper.
Examples of smoking articles in accordance with embodiments are described
below.
Unless specified otherwise, testing of the smoking articles was carried out
according to
ISO 3308:2000, in which a 35 ml puff of 25 duration is taken every 6os.
Example 1
An exemplary cigarette was produced having the filter arrangement as
illustrated in
Figure 4 and a circumference of about 23.4mm. The net weight of tobacco in the
tobacco rod was 56o mg/cigarette. The paper wrapper basis weight was 28 g/m2.
The
burn additive level was 1%. The total filter length was 34mm, connected to a
tobacco
rod having a length of 56mm giving a total cigarette length of 9omm. The tip
ventilation was arranged to be about 68%. The pressure drop across the filter
was
about loommWG. The number of puffs achieved using these parameters was about
9.5
delivering about 5mg of tar.
Example 2
CA 03135683 2021-09-30
WO 2020/201716
PCT/GB2020/050782
- 14 -
An exemplary cigarette was produced having the filter arrangement as
illustrated in
Figure 4 and a circumference of about 23.4mm. The net weight of tobacco in the
tobacco rod was 630 mg/cigarette. The paper wrapper basis weight was 28 g/m2.
The
burn additive level was 1%. The total filter length was 27mm, connected to a
tobacco
rod having a length of 63mm giving a total cigarette length of 9omm. The tip
ventilation was arranged to be about 67%. The pressure drop across the filter
was
about 90mmWG. The number of puffs achieved using these parameters was about ii
delivering about 7mg of tar.
io .. Example 3
An exemplary cigarette was produced having the filter arrangement as
illustrated in
Figure 4 and a circumference of about imm. The paper wrapper basis weight was
28
g/m2. The burn additive level was 1%. The total filter length was 27mm,
connected to a
tobacco rod having a length of 63mm giving a total cigarette length of 9omm.
The tip
/5 ventilation was arranged to be about 72%. The pressure drop across the
filter was
about 177mmWG. The number of puffs achieved using these parameters was about
10.3 delivering about 6.1mg of tar.
The various embodiments described herein are presented only to assist in
20 understanding and teaching the claimed features. These embodiments are
provided as
a representative sample of embodiments only, and are not exhaustive and/or
exclusive.
It is to be understood that advantages, embodiments, examples, functions,
features,
structures, and/or other aspects described herein are not to be considered
limitations
on the scope of the invention as defined by the claims or limitations on
equivalents to
25 the claims, and that other embodiments may be utilised and modifications
may be
made without departing from the scope of the claimed invention. Various
embodiments
of the invention may suitably comprise, consist of, or consist essentially of,
appropriate
combinations of the disclosed elements, components, features, parts, steps,
means, etc,
other than those specifically described herein. In addition, this disclosure
may include
30 other inventions not presently claimed, but which may be claimed in
future.
