U.S. patent application number 11/006307 was filed with the patent office on 2005-06-02 for smoking article aerosol generating means.
This patent application is currently assigned to British American Tobacco (Investments) Limited. Invention is credited to Beven, John Lawson, Dittrich, David John, Greig, Colin Campbell, Hook, Richard Geoffrey, McAdam, Kevin Gerard, O'Reilly, Rosemary Elizabeth.
Application Number | 20050115579 11/006307 |
Document ID | / |
Family ID | 26305572 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050115579 |
Kind Code |
A1 |
Beven, John Lawson ; et
al. |
June 2, 2005 |
Smoking article aerosol generating means
Abstract
The invention relates to a smoking article (1) having a high
proportion of non-combustible, inorganic material and a relatively
low level of visible sidestream. The smoking article comprises a
substantially non-combustible, wrapper (5) which extends along the
full length of the smoking material rod and enwraps a combustible
fuel source (6) and aerosol generating means (7), both of which
extend substantially along the length of the smoking material rod.
Various suitable fuel source system and aerosol generating systems
are described. The article has a visible burn line which advances
along the article and produces an ash which can be removed by the
smoker in the normal way.
Inventors: |
Beven, John Lawson;
(Thurleston, GB) ; Dittrich, David John;
(Southampton, GB) ; Greig, Colin Campbell;
(Redlynch, GB) ; Hook, Richard Geoffrey;
(Winchester, GB) ; McAdam, Kevin Gerard;
(Southampton, GB) ; O'Reilly, Rosemary Elizabeth;
(Eastleigh, GB) |
Correspondence
Address: |
PITNEY HARDIN LLP
7 TIMES SQUARE
NEW YORK
NY
10036-7311
US
|
Assignee: |
British American Tobacco
(Investments) Limited
|
Family ID: |
26305572 |
Appl. No.: |
11/006307 |
Filed: |
December 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11006307 |
Dec 7, 2004 |
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10389087 |
Mar 14, 2003 |
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10389087 |
Mar 14, 2003 |
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09577919 |
May 24, 2000 |
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6578584 |
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Current U.S.
Class: |
131/347 |
Current CPC
Class: |
A24D 1/22 20200101; A24B
15/165 20130101; A24D 1/02 20130101; A24C 5/00 20130101 |
Class at
Publication: |
131/347 |
International
Class: |
A24F 001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 1994 |
GB |
941797C.2 |
Aug 2, 1995 |
GB |
9515836.6 |
Claims
What is claimed is:
1. A smoking article aerosol generating means comprising 95-30%
inorganic, non-combustible binder, 45-90% non-combustible inorganic
filler material and 5-30% aerosol forming means.
2. A smoking article aerosol generating means comprising
non-combustible inorganic filler matter, aerosol forming means and
at least one inorganic binder selected from the group consisting of
potassium silicate and magnesium oxide in combination with
potassium silicate, or cement.
3. A smoking article aerosol generating means according to claims 1
or 2, wherein the non-combustible inorganic filler material is at
least one selected from the group consisting of perlite,
vermiculite, diatomaceous earth, colloidal silica, chalk, magnesium
oxide, magnesium sulphate, magnesium carbonate, and other low
density, non-combustible inorganic filler materials.
4. A smoking article aerosol generating means according to claims 1
or 2, wherein the aerosol forming means comprises one or more of
polyhydric alcohols, esters, or high boiling point
hydrocarbons.
5. A smoking article aerosol generating means according to claim 3,
wherein the aerosol forming means comprises one or more of
polyhydric alcohols, esters, or high boiling point
hydrocarbons.
6. A smoking article aerosol generating means according to claim 5,
wherein the aerosol forming means is one or more of glycerol,
propylene glycol, triethylene glycol, triethyl citrate or
triacetin.
7. A smoking article aerosol generating means according to claim 5,
wherein the organic binder is selected from one or more of the
classes of cellulose derivatives, cellulose ethers, alginic
binders, gums, gels, pectins or starches.
8. A smoking article aerosol generating means according to claim 7,
wherein the organic binder is one or more of sodium carboxymethyl
cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl
cellulose, ammonium alginate, sodium alginate, sodium calcium
alginate, calcium ammonium alginate, potassium alginate, magnesium
alginate, triethanol-amine alginate, propylene glycol alginate,
aluminum alginate, copper alginate, zinc alginate, silver alginate,
gum Arabic, gum ghatzi, gum tragacanth, Karaya gum, locust bean
gum, acacia gum, guar gum, quince seed gum, xanthan gum; agar,
agarose, carregeenans, fucoidan or furcelleran.
9. A smoking article aerosol generating means according to claims 1
or 2, wherein the aerosol generating means comprises an expansion
medium.
10. A smoking article aerosol generating means according to claims
1 or 2, wherein the aerosol generating means comprises flavouring
agents.
Description
[0001] This application is a division of Ser. No. 10/389,087 filed
Mar. 14, 2003, which is a continuation of U.S. Ser. No. 09/577,919
filed May 24, 2000, which is a continuation of U.S. Ser. No.
08/793,524 filed Feb. 27, 1997 which issued as U.S. Pat. No.
6,095,152 on Aug. 1, 2000, all of which are incorporated by
reference herein. U.S. Ser. No. 08/793,524 is a national stage
application of PCT/GB95/02110 and claims priority under 35 U.S.C.
.sctn.119 from UK 9417970 filed Sep. 7, 1994 and UK 9515836 filed
Aug. 2, 1995.
[0002] The present invention relates to smoking articles, and in
particular to smoking articles which have an other than
conventional structure and combustion regime, yet which have the
outward appearance similar to a conventional smoking article.
[0003] Many attempts have been made to produce a smoking article
which provides the smoker with an aerosol which is similar to
tobacco smoke. Some ideas have centred on generating an aerosol
vapour from an aerosol generating means by heating the aerosol
generating means with a surrounding fuel source, such as cut
tobacco. Smoke from the fuel source is prevented by a smoke barrier
from reaching the smoker's mouth, whilst the aerosol vapour can
pass to the smoker. These can be seen in U.S. Pat. No. 3,258,015
(Ellis) and U.S. Pat. No. 3,356,094 (Ellis). The first of these
proposed a smoking article having an outer cylinder of fuel with
good smouldering, characteristics, preferably cut tobacco or
reconstituted tobacco, surrounding a metal tube containing tobacco,
reconstituted tobacco or other source of nicotine and water vapour.
A substantial disadvantage of this article was the ultimate
protrusion of the metal tube as the tobacco fuel was consumed.
Other disadvantages include the formation of substantial tobacco
pyrolysis products and substantial tobacco sidestream smoke. This
design was later modified in the second patent mentioned above by
employing a tube made out of a material such as inorganic salts or
an epoxy bonded ceramic, which became frangible on heating and was
discharged as an ash by the smoker. In this invention also there
are substantial tobacco pyrolysis products and, because of the
combustion of tobacco, visible sidestream smoke.
[0004] Aerosol inhalation devices such as European Patent
Applications, Publication Nos. 0 174 645 and 0 339 690 describe
means of using heat transfer from a fuel element to physically
separate aerosol generating means. The main feature of these
inventions is that the aerosol generating means is always
physically separate from the fuel element and is always heated by
heat transfer from a heat conducting member, never burned. To this
end the fuel element is always short, located to one end of the
smoking article and kept out of direct contact with the aerosol
generating means.
[0005] Other and mainly more recent devices have included GB 1 185
867 (Synectics), U.S. Pat. No. 5,060,667 (Strubel) and EPA 0 405
190 (R. J. Reynolds). In all of these devices the patentee has
arranged the fuel element as an annulus around aerosol generating
means.
[0006] GB 1 185 857 provided a substantially inorganic smoke of
readily absorbable silts to the smoker and produced an ash which
could be removed in normal fashion by the smoker. However, the
smoking article is presumed to have given off an amount of visible
sidestream smoke because of the cellulosic components within
individual items of the smoking article.
[0007] U.S. Pat. No. 5,060,667 provided a co-axially arranged
tobacco-containing fuel element encircled by a metallic heat
transfer tube with a flange portion at the end to be lit in order
to prevent smoke from the burning tobacco from passing through the
flavour source material circumscribing the heat transfer tube. Only
aerosol from the flavour source material passes to the smoker. The
device does not burn down and tobacco material is combusted, as
well as providing the flavour source material, thereby producing
visible sidestream smoke and utilising a high percentage of a
costly item such as tobacco.
[0008] EPA 0 405 190 seeks to provide a smoking article which
provides the user with the pleasures of smoking by heating without
burning tobacco. Most of the articles comprise an annular
carbonaceous fuel segment, a physically separate aerosol generating
means disposed concentrically within the fuel segment, a barrier
member between the fuel segment and the aerosol generating means,
which substantially precludes fluid flow radially therethrough and
which is disposable as the smoking article is smoked, and a
mouthend segment. As the fuel source is disposed annularly around
the aerosol generating means it is advantageous to surround the
fuel source longitudinally with an insulating sleeve which may then
be wrapped with a conventional wrapper. One alternative embodiment
is postulated which comprises a coaxial carbonaceous fuel source of
slow burning rate encircled along its longitudinal length by an
insulation member, which in turn is encircled along its length by
tobacco wrapped in a paper wrapper. The tobacco is only heated and
not burnt, as in the other embodiments, but unlike the other
embodiments of EPA 0 405 190 the device cannot burn down as tobacco
would then be burnt. No actual practical embodiment is described
and thus this embodiment appears to be an armchair, or paper,
proposal. The patentees appear to have had some difficulty in
reducing to practice this particular concept. This concept also
utilises considerable amounts of expensive tobacco, to provide the
aerosol source material, which the smoker never truly
experiences.
[0009] U.S. Pat. No. 2,998,012 discloses a smoking article having a
non-combustible wrapper of woven, glass fibres with one or more
adhesive materials, calcium carbonate to prevent flaming, propylene
glycol as a plasticiser and a diatomaceous earth to render the
wrapper impermeable and cooler to the touch. A disadvantage of this
construction is that the wrapper still maintains a predominantly
fibrous characteristic of woven glass fibres. Such a wrapper would
be unnaceptable for a commercial smoking article. U.S. Pat. No.
4,961,438 discloses a smoking device which does not burn down along
its length which by means of a smouldering heat source heating air
drawn into the device liberates aerosol from an aerosol forming
material disposed on a substrate. The wrapper of the device is a
non-combustible tube having high heat conductivity. Such high heat
conductivity is undesirable for a commercial smoking article. The
wrapper of the present invention seeks to overcome these
deficiencies.
[0010] It is an object of the present invention to provide a
smoking article which does not produce substantial tobacco
pyrolysis products.
[0011] It is a further object of the present invention to provide a
smoking article which exhibits very little visible sidestream
smoke, and considerably less visible sidestream smoke than prior
proposed conventional smoking articles comprising tobacco rods of
cut tobacco wrapped in a paper wrapper containing a visible
sidestream reducing compound or being visible sidestream reducing
paper.
[0012] It is another object of the invention to fulfil the above
objectives whilst maintaining a substantially conventional outward
appearance of a smoking article as we know the same today.
[0013] It is also an object of the invention to preserve the
physical elements of the smoking process, including the ashing of a
cigarette to produce an ash which can be removed by the smoker in
the normal way.
[0014] The present invention provides a smoker article having a
smoking material rod comprising a substantially non-combustible
wrapper extending substantially along the length of the smoking
material rod and enwrapping a combustible fuel source extending
substantially along the length of the smoking material rod and
aerosol generating means extending substantially along the length
of the smoking material rod.
[0015] As used herein the terms `smoking material rod` or `smoking
material` are merely intended to mean that part of the smoking
article which is contained within the substantially non-combustible
wrapper and should not have imported therein any association as to
the combustibility or otherwise of individual components of the rod
of the smoking material.
[0016] The present invention further provides a smoking article
having a smoking material rod comprising a substantially
non-combustible wrapper extending substantially along the length of
the smoking material rod and enwrapping a combustible fuel source
extending substantially along the full length of the smoking
material rod, and aerosol generating means being disposed between
the fuel source and the wrapper and extending substantially along
the length of the smoking material rod.
[0017] The present invention provides a substantially
non-combustible smoking article wrapper comprised of predominantly
non-combustible inorganic filler material, a binder, optionally a
plasticiser, and optionally a small amount of cellulosic fibre
material.
[0018] Preferably the non-combustible inorganic filler material is
a particulate material and even more preferably is a non-metallic
material.
[0019] This invention also provides a method of producing a
substantially non-combustible smoking article wrapper comprising
predominantly non-combustible inorganic filler material and a
binder, the method comprising producing a mixture of the
non-combustible inorganic filler material and a binder, extruding
the mixture to provide a hollow tube, and contacting the hollow
tube with a material which causes the hollow tube to set
rapidly.
[0020] The material which causes the hollow tube to set rapidly may
be a water scavenging substance which removes water contained in
the extrudate. Alternatively the material may be a solution which
renders a soluble binder in the mixture insoluble, or a hydrophilic
substance which removes water from an aqueous-containing
mixture.
[0021] The present invention also provides a smoking article fuel
source of substantially the whole length of a smoking article, the
fuel source comprising carbonaceous material, an inorganic
non-combustible binder and optionally a burn promoter.
[0022] The present invention provides a smoking article fuel source
of substantially the whole length of a smoking article, the fuel
source comprising carbon, non-combustible inorganic filler
material, organic binder, optionally plasticiser and optionally
inorganic binder.
[0023] The present invention provides smoking article aerosol
generating means comprising a non-combustible inorganic filler
material, aerosol forming means, and an organic or inorganic
binder.
[0024] The present invention also provides a smoking article
aerosol generating means comprising an organic filler material,
aerosol forming means, an organic binder and optionally a
non-combustible inorganic filler material.
[0025] The present invention provides a smoking article aerosol
generating fuel source comprising a non-combustible inorganic
filler material, aerosol forming means, an organic or inorganic
binder and carbon.
[0026] The present invention further provides a smoking article
aerosol generating fuel source comprising organic filler material,
optionally a non-combustible inorganic filler material, aerosol
forming means, organic binder and carbon.
[0027] Substantially Non-Combustible Wrapper
[0028] Preferably the substantially non-combustible wrapper is
comprised of predominantly non-combustible inorganic filler
material. The term `predominantly` as used herein means at least
about 65% and usually 70%. The inorganic filler material
advantageously yields very little or substantially no visible
sidestream smoke when the smoking article is lit. Preferably the
non-combustible wrapper comprises at least 80%, and more preferably
at least 90% inorganic filler material by weight of the wrapper.
Advantageously the non-combustible inorganic filler material is one
or more of perlite, vermiculite, diatomaceous earth, colloidal
silica, chalk, magnesium oxide, magnesium sulphate, magnesium
carbonate or other low density, non-combustible inorganic filler
materials known to those skilled in the art.
[0029] The non-combustible wrapper may comprise a small amount of
cellulosic fibre material. Preferably the fibre material comprises
less than 10%, more preferably less than 5%, and even more
preferably less than 2% by weight of the non-combustible wrapper.
Most advantageously the fibre material is not present in the
wrapper.
[0030] Preferably the wrapper comprises a binder and/or a
plasticiser. These components may be present at up to 30% by weight
of the wrapper. Advantageously the binder is not present at more
than 25% by weight of the wrapper. The exact proportions will
depend on the taste characteristics, acceptable visible sidestream
smoke emission and strength of the desired product, and the
processing techniques used. The binder may be present at about
8-10% by weight of the wrapper, although it may be present at about
5% or less by weight of the wrapper. The binder may be organic
binders, for example, cellulose derivatives, such as sodium
carboxymethylcellulose, methyl cellulose, hydroxypropylcellulose,
hydroxyethyl cellulose or cellulose ethers, alginic binders
including soluble alginates such as ammonium alginate, sodium
alginate, sodium calcium alginate, calcium ammonium alginate,
potassium alginate, magnesium alginate, triethanol-amine alginate
and propylene glycol alginate or insoluble alginates which can be
rendered soluble by the addition of solubilising agents, such as
ammonium hydroxide. Examples of these include aluminium, copper,
zinc and silver alginates. Alginates which are initially soluble
but which, during processing, undergo treatment to render them
insoluble in the final product may also be used, e.g. sodium
alginate going to calcium alginate (see below). Other organic
binders include gums such as gum arabic, gum ghatti, gum
tragacanth, Karaya, locust bean, acacia, guar, quince seed or
xanthan gum, or gels such as agar, agarose, carrageenans, fucoidan
and furcellaran. Pectins and pectinaceous materials can also be
used as binders. Starches can also be used as organic binders.
Other suitable gums can be selected by reference to handbooks, such
as Industrial Gums, Ed. Whistler (Academic Press). Combinations of
the above may also be used. Inorganic non-combustible binders, such
as potassium silicate, magnesium oxide in combination with
potassium silicate, or some cements, for example, and mixtures
thereof, may be used.
[0031] The wrapper, although not giving much, if any, visible
sidestream smoke, does produce ash of an acceptable colour and
quality. The smoking article also has a visible burn line which
advances along the article and enables the smoker to determine
whether the article is alight and to monitor the smoking process.
The visible burn line may be formed as a result of burning the
organic binder. Alternatively, colour changing compounds can be
included in the wrapper composition. Colourants which give the
wrapper an other than white colour may also be included. These
colourants may also change colour as heating occurs, providing a
visible burn line, e.g. CuSO4.5H.sub.2O.
[0032] The nature of the binder selected will also determine the
permeability of the outer wrapper. Binders, such as sodium
carboxymethylcellulose and propylene glycol alginate, have been
found to be particularly-effective at producing an outer wrapper
sufficiently permeable to sustain combustion of the fuel source
within the wrapper. The latter binder gave the more permeable outer
for the same outer wrapper composition. Hydration time of some
binders can play a part in determining the efficacy of the binders.
Conventionally understood strong binders such as
hydroxypropylcellulose can be used at lower levels to increase the
wrapper permeability but this has to be balanced against the
strength of the wrapper.
[0033] The plasticiser may be present in the wrapper at up to 20%
by weight thereof. The plasticiser is preferably present at about
10% or less, preferably 5% or less, by weight of the wrapper. The
plasticiser may be glycerol, propylene glycol, or low melting point
fats or oils for example. Depending on the method of production
selected for the wrappers, the plastisicer may be absent from the
wrapper composition. The plasticiser helps in the drying stages of
the wrapper to prevent shape distortion, particularly if direct
heat, e.g. hot air, is the drying medium. The amount of
plasticiser, binder or other organic filler material will affect
the appearance of the burn line, i.e. the burn line width, and the
amount of visible sidestream of the article. Preferably the width
of the burn line is not greater than 10 mm, is preferably not more
than 5 mm and more preferably is between 2-3 mm in width. The width
of the burn line depends on the composition of the burnable
material in the article.
[0034] The wrapper may comprise materials which provide an odour to
any sidestream smoke which may come from the article. Suitable
deodorisers include citronellal, vanillin and geraniol, for
example.
[0035] The wrapper may be formed by producing a thick slurry of the
wrapper components, coating the slurry about a rotating mandrel,
and removing excess moisture by physical or chemical means.
Alternatively, the slurry may be cast as a sheet on a drum or band
caster, or extruded as a hollow tube, through a `torpedo` die-head,
for example, which has a solid central section, or extruded as a
sheet material. The slurry could be sprayed, coated or pumped onto
a suitably shaped fuel/aerosol assembly.
[0036] The extrusion process is suitably carried out at a pressure
which does not detrimentally affect the wrapper permeability and is
suitably not greater than 3-4 bar (300-400 kPa) at the extruder die
of a ram extruder, for example, and not more than 9 bar (900 kPa)
for an APV Baker Perkins screw extruder. The extrusion process may
require foaming to occur at the die exit to produce a cellular
structure, in which case greater pressure can be exerted, at the
die, whilst retaining permeability.
[0037] After extrusion or coating the hollow extrudate or coated
mandrel is suitably subjected to heat at or exit the die to drive
off excess moisture. The wrapper slurry may comprise a heat
activated binder, such as potassium silicate, magnesium oxide, or
hydroxypropylcellulose at temperatures above 40-50.degree. C., for
example. Subjecting the coated mandrel or hollow extrudate to heat
would activate the binder causing the wrapper to set. Infa-red or
microsave heating is advantageous as direct heating, e.g. the use
of hot air blowers, can affect the shape of the extrudate,
especially at temperatures of greater than 100.degree. C.
[0038] Extrusion may be carried out using a single or double screw
extruder, a ram extruder or slurry pump.
[0039] The wrapper suitably has a thickness within the range of
0.1-1.0 mm, although 2-3 mm may be desirable. The thickness
required depends on the weight and permeability of the wrapper.
Thus, a dense thin wrapper or a thick low density wrapper could be
provided, depending on the composition of the wrapper
materials.
[0040] Alternative setting methods for the wrapper include the use
of water scavenging substances. These substances remove water from
the wrapper slurry thereby, in effect, drying the wrapper. For
example, light magnesium oxide can be in the wrapper slurry mixture
at up to 45% by weight of the dry slurry constituents, depending on
the residence time in the extruder and the temperature in the
extruder. The addition of magnesium oxide can also have
advantageous visible sidestream reducing effects. Alternatively,
the wrapper material can be extruded into an ethanol bath, or other
strongly hydrophilic substance, the ethanol scavenging the water
from the extrudate. A further alternative is the precipitation of
an insoluble alginate from a soluble alginate in the extruded
wrapper. This can be achieved by, for example, extruding a hollow
tube of, for example, sodium alginate-containing wrapper material
into a bath of simple electrolyte(s), for example, 1.0M calcium
chloride solution. The calcium ions substitute for the sodium ions
and cause the extrudate to set extremely quickly. In the latter two
methods, spraying of the water scavenger onto the extrudate or
wrapper sheet may be carried out instead of passing the extrudate
into a bath.
[0041] Some precipitation can be achieved by adding a sub-critical
level of a precipitating agent into the extruder barrel, then
completely precipitating the structure by raising the level of the
precipitating agent post extrusion. Other precipitation methods
include precipitation of the extrudate into a highly ionic
electrolyte bath or into a water miscible non-solvent for the
alginate.
[0042] A further method includes, as briefly mentioned above with
respect to the binders, use of a conventionally insoluble alginate
as the binding material by rendering it soluble with a solubilising
agent and then setting of the wrapper structure by removal of the
solubilising agent or addition of a sequestering agent.
[0043] These methods may be used sequentially, e.g. the wrapper may
be set by precipitating a soluble alginate containing wrapper
material in a bath containing calcium ions. The extrudate may be
subsequently passed into a bath of water scavenging agent, such as
ethanol, and then heated to drive off liquid residues.
Alternatively, after setting the wrapper may be dried using the
methods described above.
[0044] These methods are particularly effective for achieving a
good shape to the extrudate because of the speed of the reaction
and the lack of volume reduction in the processes, particularly the
drying stages.
[0045] The wrapper may have a rigid structure, although we have
found that flexible wrappers can be produced using sodium alginate
as the binder, which is then precipitated to form calcium alginate
and then slowly dried. Flexibility is advantageous in terms of the
increased robustness of the product during machine and manual
handling.
[0046] The wrapper suitably has a air permeability within the range
of 1-300 Coresta Units (cc/min//cm.sup.2/10 cm WG). Permeability
can be controlled by a number of methods, such as coating an
extrudate with a film forming or other permeability reducing agent.
Alternatively, sacrificial molecules can be introduced into the
wrapper mixture, which molecules can be removed after the formation
of the structure by moderate temperature or chemical reaction to
increase the permeability of the wrapper structure.
[0047] Alternatively, the wrapper may be a cellulose-based wrapper,
such as conventional cigarette paper, which has been treated to
prevent the wrapper from burning and thereby producing visible
sidestream smoke. Preferably the treated wrapper will char and
therefore provide a visible burn line. The paper should also
produce an ash which can be knocked off by the smoker.
[0048] The ashing characteristics of the wrapper should be such
that, unburnt, the wrapper is strong enough or flexible enough to
resist digital pressure prior to, and during smoking, but upon
thermal degradation of the wrapper the structure is considerably
weakened, leaving an ash which can be readily disintegrated by
pressure or a flicking movement. Some wrappers may require ash
charring agents which char to leave some black residue to simulate
conventional cigarette ash.
[0049] Fuel Source
[0050] Preferably the fuel source extends continuously from the
mouth end of the smoking article to the lighting end thereof,
excluding any filter or mouthpiece element. In the alternative, the
fuel source may comprise a number of sections closely located so
that burning of the fuel source does not cease.
[0051] Advantageously, the end of the article to be lit has the
appearance of a conventional article. Suitably the end of the
smoking article at the end to be lit is of a tobacco-like or dark
colour, e.g. brown.
[0052] The fuel source may be provided by three distinct systems,
but overlap may occur between them. In these systems the fuel
source is physically discrete from the aerosol generating
means.
[0053] When physically discrete from the aerosol generating means
and in the form of a rod, in a first system the fuel source is
suitably prepared from carbonaceous material by pyrolysing wood,
such as rods of balsa wood, cotton, rayon, tobacco or other
cellulosic containing material, which are prepared to a shape which
is particularly useful in the present invention. In this system,
the fuel source comprises at least 85% by weight pyrolysed
carbonaceous material. Preferably the fuel source comprises at
least 90% carbonaceous material. A burn promoter such as, for
example, potassium nitrate, potassium citrate or potassium
chlorate, is also advantageously present at 10% or less by weight
of the fuel source. Other suitable burn promoters would be known to
those skilled in the art. Alternatives for an almost wholly
carbon-containing system include the use of carbon fibres or carbon
aerogels.
[0054] The term `carbon` as used herein can be taken to cover a
material which is substantially solely carbon and any carbon
precursors, such as carbonaceous material. As used herein the term
carbonaceous includes material which has been pyrolysed, which
material preferably contains carbon, although some incomplete
combustion products may still be present. Ready pyrolysed coconut
fibre may, for example, be the carbonaceous material from which
carbon is derived.
[0055] In a second system, the fuel source may be a substantially
inorganic system and comprise an inorganic, non-combustible binder,
selected from the list outlined above with respect to the wrapper,
for example, Portland cement, or potassium silicate. The binder may
be present within the range of 10-65% by weight of the fuel source.
The binder is advantageously present in an amount of less than 40%
by weight of the fuel source. The fuel source may also comprise
5-20% of a burn promoter, preferably less than 10%, by weight of
the fuel source. The fuel source may comprise 5-70% carbon,
advantageously at least 55% carbon, and more suitably at least 60%
carbon by weight of the fuel source. However, we have found that
acceptable combustion characteristics can still be maintained with
about 30% carbon, 60% inorganic, non-combustible binder and less
than about 10% burn promoter when the fuel source is provided as a
rod. A proportion of inorganic, non-combustible filler in the range
of 0-60% may also be incorporated in this alternative to reduce the
density of the fuel source or to improve the strength of the fuel
source.
[0056] The fuel source in this instance may, for example, be a
shaped rod of carbon having a porous structure to sustain
continuous combustion throughout the length of the fuel source.
Shaping techniques which do not disadvantageously lose water during
shaping of the rod are preferred. Shaping of a thick slurry
comprising carbon and a binder within a hollow tube and removing
the shaped rod from the tube after a curing or setting stage is one
method of fuel source production. Alternatively, an extrusion
process may be used.
[0057] In the third system, the fuel source is a partially organic
system and comprises 15-70% carbon, 84-5% non-combustible inorganic
filler material such as, for example, one or more of the inorganic
filler materials listed above with respect to the wrapper, 0-5%
plasticiser, such as one or more of low melting point fats or low
melting point oils, and 1-20% organic binder, such as cellulosic,
alginic or pectinaceous binders, for example, and/or the other
organic binders described above with respect to the wrapper. A
mixture of inorganic or organic binders may be used, the inorganic
binder being present within the range of 0-20% by weight of the
fuel source. The plasticiser is included to improve the mechanical
strength and flexibility of the fuel source and the amount present
together with the amount of organic binder, should not provide a
significant quantity of mainstream smoke. A high level of organic
binder might be utilisable if the binder produces a low level of
mainstream smoke, i.e. particulate matter. The amount of carbon is
subject to the type and amount of binder and/or filler utilised,
thus the range above should not be considered too limiting. The
amount of carbon required will also depend on the composition of
the outer wrapper. Furthermore, at low levels of carbon usage the
outer wrapper will need to be more permeable than at higher carbon
levels. Most suitably the carbon is present in the range of
25-35%.
[0058] Extrusion may be a low pressure extrusion through a nozzle
using a driving force not substantially greater than atmospheric
pressure, or a high pressure extrusion process. Foaming of the
extrudate to achieve a cellular structure may be required,
particularly in the second and third systems, depending on final
product design. In the second system, foaming could be achieved by
the introduction of air entraining agents instead of a proportion
of the inorganic, non-combustible binder and/or the inorganic
filler, if present. The air-entraining agents can be powdered or
liquid additives or porous particulate materials. In the third
system when foaming is required it may be achieved by the presence
of, for example, a polysaccharide expansion medium such as starch,
and the expanding effect of water under high temperature and
pressure. The expansion medium would replace the binder or the
plasticiser or inorganic filler, if present. Alternative expansion
mediums, such as pullulan or other polysaccharides, including
cellulose derivatives, may be used. Other agents capable of causing
foaming may be solid foaming agents, such as sodium bicarbonate,
inorganic salts and organic acids providing in situ gaseous agents;
propane or isobutane as organic gaseous agents; nitrogen, carbon
dioxide or air as inorganic gaseous agents; and volatile liquid
foaming agents, such as ethanol and acetone, for example.
Polysaccharide expansion mediums are preferred because of their
ease of usage and safety aspects.
[0059] Extrusion may produce thin elongate strands, which may be
longitudinally arranged, or more solid thicker rods, preferably
co-axially located within the smoking material rod. In the first
two alternatives, i.e. the pyrolysed structure and the inorganic
system, a central rod could be replaced by several thinner strands.
Extruded sheet may also be produced, then shredded to produce cut
filler similar to cut tobacco filler. These processes are all
suitable for the production of the fuel source, the aerosol
generating means and the combined aerosol generating fuel source to
be described later. Band casting, heated drum casting and other
sheet making techniques can also be used.
[0060] In all of the above fuel source alternatives, except in the
pyrolysed rod embodiment, 0-2% fibre is optional. This also applies
to those methods of preparation of aerosol generating means which
involve casting or paper making techniques.
[0061] Aerosol Generating Means
[0062] The aerosol generating means may be provided by three
distinct systems, but overlap may occur between them.
[0063] The first system may be a substantially inorganic system
comprising 95-30% inorganic, non-combustible binder, such as those
binders described above with respect to the fuel source, 0-65%
non-combustible inorganic filler material, such as those materials
described above with respect to the fuel source, and 5-30% aerosol
forming means, as described below.
[0064] The second system may be a partially inorganic system
comprising 1-25% organic binder, 45-94% non-combustible inorganic
filler material and 5-30% aerosol forming means. The third system
may be a partially organic system comprising 1-25% organic binder,
1-94% organic filler material, 0-93% inorganic filler material and
5-30% aerosol forming means. Preferably the aerosol forming means
comprises 5-25% by weight of the mixture. These systems are
intended to be substantially non-combustible. The inorganic filler
material is therefore selected, in combination with the proportions
of the other materials, to provide substantially non-combustible
aerosol generating means. Some inorganic fillers, such as perlite,
magnesium hydroxide and magnesium oxide, readily serve to render
the aerosol generating means non-combustible. Other fillers, such
as chalk, at some incorporation levels, do not detract from the
combustibility of the aerosol generating means and as such are
unsuitable at those levels.
[0065] The organic filler material is preferably a material other
than tobacco and may include inorganic salts of organic acids, or
polysaccharide material, and should provide smoke with an
acceptable taste characteristic.
[0066] These two systems represent two ends of a spectrum in which
inorganic and organic components of the binder and filler material
can be gradually substituted for one another. The third system may
also incorporate an amount of expansion medium, such as described
above, as part of the organic filler material. An example of foamed
aerosol generating means comprises 20% organic binder, 20% aerosol
forming means, 15% starch as an expansion medium and 45% inorganic
filler material. The aerosol generating means may also comprise
flavouring means.
[0067] A small amount of fibre material may also be required in the
above systems to assist in the formation of a sheet, depending on
the manner of manufacture.
[0068] The aerosol generating means preferably comprises aerosol
forming means, such as polyhydric alcohols, glycerol, propylene
glycol and triethylene glycol, for example, or esters such as
triethyl citrate or triacetin, or high boiling point
hydrocarbons.
[0069] Flavouring agents in the smoking material rod are designed
to contribute towards an aerosol which has a unique but very
acceptable taste and flavour characteristic to the aerosol smoke.
The taste and flavour may not necessarily be designed to imitate
tobacco smoke taste and flavour. Flavouring agents may include
tobacco extract flavours, menthol, vanillin, toffee, chocolate or
cocoa flavours, for example. Colouring means, such as food grade
dyes, for example, or colourants such as liquorice, caramel or
malt, or extracts thereof, may be used to darken the colour of the
filler material. The presence of vermiculite or other inorganic
material, such as iron oxide, may also give a darker colour to the
filler material of the smoking article.
[0070] Flavouring agents may also be incorporated on or into a
substrate, which may be the aerosol generating means and/or the
fuel source, at a location close to or at the mouth end of the
smoking material rod of the smoking article, or along the length of
the smoking material rod provided that they are not affected by
combustion temperatures. The percentages given above are given
without the addition of any flavouring agent. These percentages
will be consequently reduced by the addition of flavouring agents.
Where inorganic or organic filler material is present in the
aerosol generating means or fuel source, the percentages of these
elements would be decreased as flavourants increased. Where filler
material is not present, either the carbon or aerosol forming means
would be consequently reduced as the flavourants increased.
[0071] As mentioned above, the aerosol generating means may be
formed by conventional paper-making techniques or by extrusion
techniques. The sheet material may be cut or rolled. The inorganic
filler materials of these systems can be used in the system
mixtures without pre-treatment stages before providing a complete
aerosol generating mixture. Aerosol Generating Fuel Source.
[0072] As described above both of the fuel source and the aerosol
generating means are kept substantially separate from one another,
each forming a distinct area of either fuel source or aerosol
generating means. In some instances though it may be advantageous
to combine the two elements. This can be done by mixing physically
discrete fuel source and aerosol generating material or by
producing a totally combined aerosol generating fuel source. In the
first case, a preferred embodiment is mixing the fuel source as cut
filler material with aerosol generating means as cut filler
material. Thus, an aerosol generating fuel source comprising a
mixture of physically discrete individual cut filler material is
provided, which filler material extends the full length of the
smoking material rod. This embodiment is particularly advantageous
in that it can be made in a manner very similar to conventional
cigarette making procedures by providing a mixture of cut filler
material to a cigarette making machine. In the second case, carbon
is added to the aerosol generating means composition.
[0073] The aerosol generating fuel source may be provided by three
distinct systems, but overlap may occur between them. The first
system is a predominantly inorganic system comprising 0-35%
inorganic filler material, 5-30% aerosol forming means, 30-60%
inorganic binder, 30-65% carbon and 0-10% burn promoter. The
aerosol forming means is selected from the group outlined above
with respect to the aerosol generating means. The other components
are also to be selected from the respective groups outlined above
with respect to the other elements of the invention. This also
applies to the systems described below.
[0074] The second system is a partially inorganic system comprising
86-0% inorganic filler material, 5-30% aerosol forming means, 1-25%
organic binder and 8-60% carbon.
[0075] The third system is a more organic system comprising 93-0%
organic filler material, 0-93% inorganic filler material, 5-30%
aerosol forming means, 1-25% organic binder and 1-60% carbon. The
more organic system may be foamed by the presence of an expansion
medium and/or expansion agent, at the levels described above.
[0076] Preferably the aerosol forming means comprises 5-25% by
weight of the mixture.
[0077] The binders and aerosol forming means for the above aerosol
generating fuel sources may be any one or more of the binders or
aerosol forming means exemplified above.
[0078] With the increase in organic components and the respective
increase in sidestream, the permeability of the outer wrapper must
be controlled to reduce the visible sidestream given off by this
fuel source composition or, as described below, sidestream reducing
agents can be added to the wrapper to reduce the amount of
particulate matter forming the sidestream smoke. The thickness of
the outer wrapper can also be varied to reduce visible sidestream
smoke.
[0079] Structure of Article
[0080] The smoking article may be provided in a number of physical
structures. In all three fuel source systems the fuel source may be
provided as a longitudinally extending rod, strands or filaments,
advantageously located co-axially of the smoking article. The rods,
strands or filaments can be of various shapes, e.g. round, square,
star or polygonal, all of which may be hollow or solid, and may be
co-axially clustered. In the second and third system the fuel
source may also be a sheet material which can be cut to produce
shreds. Material of the third system may also be rolled to the
desired shape.
[0081] When the fuel source is provided as a central rod of either
carbonised wood or an extruded rod of the second or third fuel
systems, i.e. a cement/carbon fuel source or the partially organic
fuel system, the aerosol generating means may be an annulus of cut
aerosol generating material or a roll of such material, rolled to
provide a sufficient annular density to support the fuel rod, while
still allowing air to be drawn through the article by the
smoker.
[0082] A preferred option is to provide the rod filler material as
a cut filler material. In one case, there may be provided a central
core of cut fuel material surrounded by an annulus of cut aerosol
generating material. This arrangement can also be provided with the
aerosol generating means as the core material and the fuel source
as the annulus material. Known techniques for producing co-axial
structures for cut filler material can be used, e.g. providing a
small dimension first wrapped rod which is fed to a further
garniture and cut filler material is arranged around the first
rod.
[0083] In the alternative, if an aerosol generating fuel source is
provided, discrete cut aerosol generating means may be intimately
mixed with discrete cut fuel source material.
[0084] The overall percentages of mixed cut fuel source material
and cut aerosol generating material preferably falls within the
range of 30-35% carbon, 5-10% binder, 0-2% fibre, 5-10% plasticiser
and 40-60% inorganic material. This range may be comprised of the
individual sheets of material having the following
compositions:
[0085] Fuel source: 60-70% carbon, 7% propylene glycol alginate
binder, 1% fibre and 32-22% perlite inorganic material.
[0086] Aerosol generating means: 7% propylene glycol alginate
binder, 1% fibre, 15% glycerol plasticiser and 77% perlite
inorganic material.
[0087] These materials would typically be mixed in the ratio of
1:1. Other ratios of mixing could be used to give the desired
overall range of components described above.
[0088] If the aerosol generating means and fuel source are actually
combined together chemically, the sheet material may be cut and
provided within the outer wrapper as cut filler material. It may be
desirable to increase the proportion of fuel material in a further
combined sheet material, and to provide this material as a central
region of higher carbon density surrounded by a less
carbon-containing combined cut sheet material.
[0089] When the fuel and aerosol components are produced by
extrusion methods, they may be provided as rods, strands or
filaments. A coaxial core of several strands (or rods or filaments)
may be provided of fuel material surrounded by an annulus of
gathered strands of aerosol generating means. The vice versa
arrangement is also possible as above. A further arrangement is the
intimate inter-mixing of strands of discrete fuel source and
aerosol generating means within the outer wrapper. The rods,
strands or filaments may also be comprised of the chemically
combined aerosol generating fuel source material. These extruded
rods, strands or filaments may all be somewhat foamed, if
desired.
[0090] Where foaming to provide a cellular structure is desired, a
core of foamed fuel source may be surrounded by an annulus of
foamed aerosol generating means. This may be produced by
co-extrusion techniques using cross-head dies, for example. The
vice versa arrangement is also possible. It is also possible in all
of the above structural embodiments that only one of the core or
annulus material is foamed.
[0091] Smoking Article
[0092] Advantageously the smoking article incorporates a filter
element which may be conventional fibrous cellulose acetate,
polypropylene or polyethylene material or gathered paper material.
Multiple filter elements may also be utilised. Filter elements
having particular pressure drop characteristics, such as the filter
sold by Filtrona and known as The Ratio Filter, may also be
utilised. Disposed upon or within the material of the filter
element may be further flavouring materials, as described above,
which are released or eluted from the filter element by the aerosol
generated by the heated or burnt aerosol generation means.
[0093] Disposed about the fuel source at the mouthend thereof
and/or between the fuel source and the filter element may be a
firebreak; The firebreak may suitably comprise a more densely
packed region of the material comprising the aerosol generating
means. Preferably the firebreak also comprises aerosol forming
means to enhance the delivery of aerosol to the smoker, as well as
protecting the smoker from potentially over-hot smoke as the length
of the smoking article decreases. Alternatively, the firebreak may
comprise a band of burn retarding material on the exterior of the
wrapper, for example. The firebreak may be substantially
combustible or substantially non-combustible material.
[0094] The proportions of the non-inorganic materials are selected
to give a smoking article which exhibits extremely low visible
sidestream smoke. A conventional smoking article comprises cut
tobacco wrapped in a paper wrapper. A smoking article which
exhibits low visible sidestream smoke is required to give a
reduction of at least 30% in rate of sidestream particulate matter,
known as NFDPM (nicotine free, dry particulate matter) emission, in
order for there to be a reduction in visible sidestream which is
visible to the naked eye. European Patent Application, Publication
No. 0 404 580 describes a smoking article having a paper wrapper
which is extremely effective in reducing visible sidestream smoke.
Reductions in visible sidestream particulate matter of up to 60%
against control cigarettes without the inventive papers are
achievable with smoking articles incorporating the paper according
to that application. When smoking articles according to the present
invention and cigarettes according to EPA-0 404 580 are smoked head
to head, smoking articles according to the present invention have
even less visible sidestream than the cigarettes of EPA 0 404 580.
Smoking articles of the present invention are thus effective to
provide visible sidestream reductions far greater than any other
smoking article available at the present time.
[0095] Smoking articles according to the present invention
preferably comprise at least 50% by weight of the article as
inorganic material.
[0096] In order that the present invention may be easily understood
and readily carried into effect, reference will now be made, by way
of example to the following diagrammatic drawings, in which:
[0097] FIG. 1 shows, in longitudinal cross-section, a smoking
article according to the present invention,
[0098] FIG. 1a shows, in axial cross-section, another embodiment of
a smoking article according to FIG. 1,
[0099] FIG. 2 shows, in longitudinal cross-section, a further
smoking article according to the present invention,
[0100] FIG. 3 shows, in longitudinal cross-section a yet further
embodiment according to the present invention, and
[0101] FIG. 4 shows another embodiment of the present invention in
longitudinal cross-section.
[0102] One embodiment of a smoking article of the present invention
is depicted in FIG. 1 of the drawings hereof. FIG. 1 shows a
cigarette 1 comprising a smoking material rod 2 and a filter
element 3. The filter element 3 is composed of conventional fibrous
cellulose acetate tow but may be of any other type of fibrous
material with conventional pressure drop and filtration efficiency,
or a high pressure drop, low filtration efficiency, non-fibrous
material, if appropriate. The filter element 3 is attached to the
smoking material rod 2 by a tipping wrapper 4. The filter element 3
may be ventilated, either using ventilation perforations produced
by laser for example, or by means of the natural permeability of
the tipping wrapper 4 and any underlying plugwrap. The smoking
material rod 2 comprises an exterior wrapper 5, a co-axially
located combustible fuel source 6 and cut smoking material 7
disposed between the fuel source 6 and the wrapper 5.
[0103] The exterior wrapper 5 comprises 1% fibre, 4% propylene
glycol alginate as a combustible binder, 5% glycerol as a
plastisicer and 90% perlite as an inorganic non-combustible filler
material. The exterior wrapper 5 has a white colour, is about 1 mm
in thickness, and looks very similar to the paper wrapper of a
conventional smoking article, or cigarette.
[0104] The co-axial fuel source 6 was produced in accordance with
the first fuel system above by pyrolysing a circular rod of balsa
wood having a diameter of about 4 mm. The shape of the balsa wood
rod is ideal for the purpose of providing an elongate, circular
fuel source. The pyrolysed rod has an acceptable strength and is
quite robust when surrounded by the cut smoking material 7. The
density of the initial rod, and also in its final form, is
important. We have found that if the fuel source is too dense after
pyrolysation insufficient oxygen reaches the interior thereof and
therefore the fuel source will not continue to burn. On the other
hand, if the density of the pyrolysed fuel source is too low then
the fuel source combusts too actively and thus too rapidly. Balsa
and ash have been found to be the more suitable woods for use in
this invention, though other wood species may be found to be
appropriate.
[0105] The smoking material 7 is an aerosol generating means
consisting of a high proportion of non-combustible, inorganic
material, namely 80% perlite, 12% glycerol aerosol forming means,
7% propylene glycol alginate binder and 1% fibre, i.e. the
partially inorganic system. The smoking material is produced by
forming a slurry of the components and making a reconstituted sheet
in accordance with standard sheet making techniques. The sheet of
reconstituted inorganic material is then cut to provide cut filler
material 7 and is disposed about the pyrolysed balsa wood fuel
source 6.
[0106] At the mouth end of the smoking article there is located a
region 9 of aerosol generating means onto which has been deposited
flavouring agents, such as vanilla and toffee, for example. More of
these flavouring agents were disposed within the filter element
3.
[0107] In operation, the cigarette 1 is lit and the cigarette burns
along the fuel source length producing very little visible
sidestream smoke. The visible sidestream smoke produced is derived
from the organic components in the smoking article and is most
visible at the end of a puff. The substantially non-combustible
wrapper chars to produce a frangible, white ash, similar to
conventional cigarette ash and which can be tapped off by the
smoker, as required. The non-combustible exterior wrapper 5 upon
charring also produces a dark burn line which advances along the
smoking article as burning progresses. The smoking article burns
back along the fuel source 6. As burning occurs an aerosol is
produced from the aerosol-generating cut smoking material 7, which
aerosol is drawn into the smoker's mouth. The aerosol, in this
instance, is predominantly glycerol and water but also comprises
vanilla and toffee flavours. Other flavours such as tobacco
extracts, nicotine compounds, or other tobacco-like flavours, give
the aerosol an acceptable taste and quality but without burning any
tobacco material. Additional flavour material is also carried on
the filter element, which material is designed to be released upon
the approach of `smoke` or aerosol from the burning
aerosol-generating smoking material rod 2, Filter flavourant is not
always required if sufficient flavour material is held in the
aerosol generating means.
[0108] FIG. 1a shows a very similar embodiment to FIG. 1 except
that in this cigarette, instead of the smoking material rod 2
incorporating cut smoking material 7, the smoking material 7' is
present as a rolled sheet 8 of smoking material which is rolled
about the longitudinal length of the fuel source 6. The rolled
sheet 8 of the smoking material 7' is attached by a line or band of
adhesive, such as propylene glycerol alginate, extending along the
length of the fuel source 6. The rolled sheet 8 of smoking material
must be rolled to allow air to pass to the burning coal of the
cigarette 1.
[0109] The smoking article 10 depicted in FIG. 2 has a similar
structural arrangement to that of FIG. 1. Identical elements of the
cigarette 11 have been given the reference numerals of FIG. 1
increased by ten.
[0110] In this embodiment the wrapper 15 comprised 1% fibre, 4.5%
propylene glycol alginate and 94.5% perlite inorganic,
non-combustible filler material. No plasticiser was present in the
wrapper.
[0111] The fuel source 16 of this embodiment is comprised of
combustible material held together with a non-combustible binder.
The fuel source 16 comprises carbon in the form of pyrolysed
coconut fibre, Portland cement and a small amount of potassium
nitrate burn promoter in the ratio of 8:4:1 respectively. The fuel
source 16 was produced by hydrating the cement with a 1.3M solution
of potassium nitrate sufficient to form a slurry, adding the
powdered carbon to the slurry with a small amount of detergent to
`wet` the carbonaceous material, and additional water to provide a
slurry of mud-like consistency. A rod of fulel material was formed
by shaping the slurry mixture within a hollow tube, the shaped rod
being expelled from within the tube once the rod had sufficient
mechanical strength after a period of drying, curing or setting.
Any excess moisture is driven off by heating after removal from the
hollow tube. The fuel source 16 had a diameter of about 4 mm.
Surrounded by filler material 17 the fuel source 16 is quite robust
and is well able to withstand normal handling in the packing
process and by the consumer.
[0112] In this embodiment, cocoa flavour was provided at a
downstream location of the aerosol generation means 17 and within
the filter element 13.
[0113] The smoking article 20 depicted in FIG. 3 is a further
refinement of the embodiment of FIG. 2. Reference numerals
referring to identical elements have again been increased by ten.
In this cigarette 21 the smoking material rod 22 comprises cut
smoking material 27 disposed about a carbon fuel source 26. The
exterior wrapper 25 is composed of two layers. An inner layer 40 is
composed of the wrapper material described in FIGS. 1 and 2. An
outer layer 41 is comprised of a coating of a visible sidestream
reducing filler, such as magnesium oxide bound by a small amount of
propylene glycol alginate. The proportions of the wrapper in total
were 79.5% perlite, 1% fibre, 4.5% propylene glycol alginate and
15% magnesium oxide. The magnesium oxide coating is capable of
further reducing the visible sidestream smoke emanating from the
smoking article 10 of FIG. 2, for example. Indeed, the visible
sidestream smoke from smoking article 20 is virtually non-existent.
However, the exterior wrapper 25 still produces a dark burn line,
the advance of which enables the smoker to determine whether the
cigarette 21 is, in fact, alight and to thereby monitor the
progress of combustion.
[0114] In the alternative to a coating of visible sidestream
reducing filler, the visible sidestream reducing filler may be
included in the wrapper furnish to form a single wrapper. A typical
composition of the treated wrapper 25 consists of 87.5% perlite
inorganic material, 4% propylene glycol alginate binder, 7.5%
magnesium oxide visible sidestream reducing filler and 1% fibre.
Levels of 15% magnesium oxide have been used effectively with 80%
perlite.
[0115] In this embodiment, tobacco extract flavours were disposed
within the filter element 23.
[0116] The drawing of FIG. 4 shows a further embodiment of the
invention in which reference numerals which refer to the same
features as in FIG. 3 have been increased by ten. The smoking
material rod 32 of cigarette 31 comprised a wrapper 35 enclosing
cut smoking material which is also combined with fuel means to
provide an aerosol generating fuel source 37. The aerosol
generating fuel source 37 together comprises a lengthwise extending
fuel source and lengthwise aerosol extending generation means. The
aerosol generating fuel source 37 comprises 55% carbon (pyrolysed
coconut fibre), 12% glycerol aerosol forming means, 7% propylene
glycol alginate binder, 1% fibre and 25% perlite inorganic
material, i.e. the partially inorganic system. This material is
produced using the reconstituted sheet method described above and
casting either on a drum or band caster. At one end of the aerosol
generating fuel source 37 there was applied chocolate and mint
flavours. Flavour material was also present in the filter element
33.
[0117] Examples of another aerosol generating fuel source from the
second aerosol generating fuel source system were also producers
which comprised as little as 10% carbon and 70% perlite inorganic
material. The other proportions remained the sane as above.
[0118] The wrapper 35 in this embodiment had the composition of
4.5% propylene glycol alginate binder and 94.5% perlite inorganic
non-combustible filler material in one instance. In another
instance, the wrapper had the composition of 4% propylene glycol
alginate, 5% glycerol plasticiser and 90% perlite.
[0119] All of the aerosol generating compositions described above
may be modified in colour by replacing up to 10% of the inorganic
filler material with a colourant, such as caramel or liquorice or
extracts thereof.
[0120] The percentages given in this specification are on a dry
weight basis. The amount of water required to make a suitable
slurry of solid components amounting to 500 g (including glycerol)
is usually about 1200 ml.
[0121] The following tables give further details of embodiments
prepared to illustrate the invention.
[0122] Table 1 gives details regarding the influence of material
formulation on the physical properties of the outer.
[0123] A slurry was prepared from hydrated binder and inorganic
material to the recipe given in Table 1. Outer wrappers were made
from the slurry to a length of 70 mm and 0.5 mm wall thickness by
use of a ram extruder. The outer wrappers were dried at exit from
the extruder die by use of two intra-red heaters placed 5-10 cm
from the extrudate. The physical properties of the outer wrappers
are detailed in Table 1.
[0124] Table 2 gives details regarding the influence of process
conditions on the efficiency of setting outer wrappers using
calcium chloride solution.
[0125] A slurry was prepared from 10 g sodium alginate, 45 g chalk
and 45 g perlite in 200 ml of water. A ram extruder was filled with
the slurry and the outer wrappers were prepared by extrusion of the
slurry through an 8 mm outer diameter, 7 mm inner diameter torpedo
die into calcium chloride solution. Firmness of the outer was
judged subjectively by a panel of three individuals, on a ten point
scale running from 1 (indicating that the extrudate was completely
unchanged by immersion in the bath) to 10 (indicating that the
extrudate was completely set and rigid).
[0126] The Table illustrates that as the number of uses of the bath
is increased, the firmness of the outer wrapper decreases. The
firmness of the outer wrapper increases as the concentration of the
electrolyte solution increases and as immersion time increases.
[0127] Table 3 gives details of the combustion limits of carbon and
glycerol based aerosol generating fuel sources using a single
strand of extruded material of 1.00 mm diameter.
[0128] Table 4 shows the effect of binder type on the combustion
characteristics of a variety of carbon and glycerol based aerosol
generating fuel sources using single strands of extruded material
of 1.00 mm diameter. Some binders are more combustible then others
and therefore influence the proportions of material used in the
aerosol generating fuel source.
[0129] Table 5 shows the effect of filler type on the combustion
characteristics of a variety of carbon and glycerol based aerosol
generating fuel sources using single strands of extruded material
of 1.00 mm diameter. Some inorganic filler materials facilitate
combustion of a range of aerosol generating fuel source mixtures.
Chalk is the preferred filler over the ranges illustrated. This
table should not necessarily be taken to indicate that the fillers
used in mixtures outside these illustrated ranges would not
burn.
[0130] The tests performed for Tables 3, 4 and 5 were performed on
single strands smouldering in free air rather than on a number of
strands within an outer wrapper in order to exclude any influence
on the combustion of the strands due to the properties of the outer
wrapper.
[0131] Table 6 gives smoke yields from filter-tipped cigarettes
which had the following construction:
[0132] A 5 mm filter was obtained from a State Express
International cigarette, the filter comprising fibrous cellulose
acetate of 2.8 filament denier of Y cross-section, 34,000 total
denier and having a pressure drop of 13 mm WG.
[0133] The substantially non-combustible outer wrapper was extruded
using a ram extruder through an 8 mm outer diameter, 7 mm inner
diameter torpedo die and the aerosol generating fuel source was
extruded as 1.00 mm diameter strands from a ram extruder, the
strands being gathered together and inserted into dried extruded
outer wrappers. The cigarette rod length, i.e. excluding the filter
element, was 67 mm. One cigarette of each was smoked under standard
machine smoking conditions in which a 35 cm.sup.3 puff of two
seconds duration is taken every minute.
[0134] The first five examples of Table 4 illustrate that carbon
fuel strands will burn without producing significant levels of
total particulate matter (TPM) even with organic material (PGA) in
the fuel strands.
[0135] The cigarettes according to the invention have very low
visible sidestream smoke levels. However, the nature of the
sidestream smoke from the inventive articles does not render the
conventional fishtail sidestream measuring apparatus described in
Analyst, October 1988, Volume 113, pp 1509-1513 a suitable
measuring apparatus. We are thus unable to provide yield details in
this respect.
1TABLE 1 Influence of Material Formulation on the Physical
Properties of the Outer Energy % Total required Whiteness % % %
Binder Plasticiser Solids Water Permeability to crush of outer
Perlite Chalk Binder Type (Glycerol) (g) (g) (CU) outer (J) (DE) 85
15 PGA 100 300 94 22.5 67.5 10 PGA 100 200 14 5.3 6.6 90 10 PGA 100
200 3.8 5.2 9.2 80 20 PGA 100 200 77 4.6 80 20 PGA 100 200 0.6 9.6
97.5 2.5 PGA 100 70 6.5 9.2 95 5 PGA 100 40 4.5 9.5 75 25 PGA 100
500 110.7 75 25 PGA 100 260 90 10 PGA 100 200 5.2 3.7 90 10 HEC 100
150 cnm 45 45 10 HEC 100 130 57 45 45 10 AA 100 120 21 90 10 AA 100
135 160 88 10 PGA 2 100 180 185 85 10 PGA 5 100 160 145 80 10 PGA
10 100 140 215 70 10 PGA 20 100 135 105 72 8 PGA 20 100 120 cnm 75
5 PGA 20 100 115 cnm 77.5 2.5 PGA 20 100 110 90 10 SCMC 100 14 95 5
SCMC 100 70 17.5 4.4 97.5 2.5 SCMC 100 110 34 3.8 85 15 SCMC 100
2.9 77.5 9 13.5 SCMC 100 100 12 85 5 10 PGA 100 161 9.3 70 20 10
PGA 100 120 9.2 65 25 10 PGA 100 79 40 50 10 PGA 100 19.5 12 45 45
10 HPC 100 95 111 90 10 NaA 100 160 65 45 45 10 NaA 100 120 6 90 10
NaCaA 100 205 70.7 45 45 10 NaCaA 100 190 90 10 Karaya gum 100 175
285 45 45 10 Karaya gum 100 130 CNM 90 10 Locust 100 150 295 Bean
gum 45 45 10 Locust 100 130 60 Bean gum 45 45 10 Acacia gum 100 8
PGA Propylene glycol alginate HEC Hydroxyethyl cellulose AA
Ammonium alginate SCMC Sodium carboxymethylcellulose NaA Sodium
alginate NaCaA Sodium calcium alginate DE total colour difference
from reference paper cnm could not measure
[0136]
2TABLE 2 Influence of Process Conditions on the Efficiency of
Setting Outer Wrappers Using Calcium Chloride solution. Calcium
Chloride Number of uses of Subjective solution strength Immersion
time in the bath prior to Firmness (M 1.sup.-1) bath (s) this
measurement of outer 0 0 0 1 1 2 0 4 1 4 0 6.5 1 6 0 7.5 1 8 0 8 1
10 0 8 1 60 0 9.5 0.1 10 0 2.5 0.5 10 0 4.7 1 10 0 6.7 2 10 0 7.7 1
10 1 7 1 10 2 6 1 10 3 6 1 10 4 5 1 10 5 5 1 10 6 4 1 10 7 3.6 1 10
8 3
[0137]
3TABLE 3 Combustion Limits of Carbon and Glycerol Based Aerosol
Generating Fuel Source (as single strand) Fuel Combustions that
burn Fuel Combustions that do not burn % % % % % % % % Carbon
Glycerol PGA Chalk Carbon Glycerol PGA Chalk 0 10 10 80 4 10 10 76
5 20 10 65 5 20 10 65 7 20 10 63 8 26 10 56 8 5 10 77 8 30 10 52 8
10 10 72 8 15 10 67 8 21.5 10 60.5 9 15 10 66 9 20 10 61 10 15.5 10
64.5 10 0 10 80 10 10 10 70 11 15 10 64 11 3 10 76 11 20 10 59 11
11 10 68 11 21 10 58 11 30 10 49 12 8 10 70 12 0 10 78 12 9 10 69
12 6 10 72 12 10 10 68 12 7 10 71 12 11 10 67 13 20 10 57 15 6 10
69 15 0 10 75 15 20 10 55 15 3 10 72 20 6 10 64 20 0 10 70 20 10 10
60 20 3 10 67 30 0 10 60 30 3 10 57 30 6 10 54 50 0 10 40
[0138]
4TABLE 4 Influence of binder type on the combustion characteristics
of various aerosol generating fuel source mixtures. Binder Type
Propylene Hydroxy Glycol Sodium Calcium Propyl Alginate Alginate
Alginate Pectin Cellulose 8% Carbon No Yes No No Yes 11% Glycerol
71% Chalk 10% Binder 12% Carbon Yes Yes No Yes Yes 11% Glycerol 67%
Chalk 10% Binder 16% Carbon Yes Yes No Yes No 11% Glycerol 63%
Chalk 10% Binder 8% Carbon Yes Yes No Yes Yes 11% Glycerol 61%
Chalk 20% Binder 12% Carbon Yes Yes No Yes Yes 11% Glycerol 57%
Chalk 20% Binder 16% Carbon Yes Yes No Yes Yes 11% Glycerol 53%
Chalk 20% Binder 8% Carbon Yes No No Yes -- 11% Glycerol 51% Chalk
30% Binder 12% Carbon Yes No No Yes -- 11% Glycerol 47% Chalk 30%
Binder 16% Carbon Yes No No Yes -- 11% Glycerol 43% Chalk 30%
Binder
[0139]
5TABLE 5 Influence of inorganic filler type on the combustion
characteristics of various aerosol generating fuel source mixtures.
Filler Type Calcium Magnesium Fuel mixture Perlite Magnesium
Bentonite Chalk Sulphate Hydroxide Kieselguhr 18.2% Carbon, No No
No Yes No No Yes 11.4% PGA, 12.5% Glycerol, 58% Filler 16.3%
Carbon, No No No Yes No No Yes 10.2% PGA, 11.2% Glycerol, 62.2%
Filler 15.8% Carbon, No No No Yes No No -- 13.2% PGA, 14.5%
Glycerol, 56.5% Filler 14.8% Carbon, No -- No Yes No No No 9.3%
PGA, 10.2% Glycerol, 65.7% Filler 13.9% Carbon, No -- No Yes No No
No 11.6% PGA, 12.8% Glycerol, 61.6% Filler 12.5% Carbon, -- No --
Yes No No No 10.4% PGA, 11.5% Glycerol, 65.6% Filler 10.5% Carbon,
No No No Yes -- No No 13.2% PGA, 14.5% Glycerol, 61.8% Filler 9.3%
Carbon, -- No No No -- No No 11.6% PGA, 12.8% Glycerol, 66.3%
Filler 8.3% Carbon, No -- -- No -- No No 10.4% PGA, 11.5% Glycerol,
69.8% Filler -- mixture not produced
[0140]
6TABLE 6 Smoke yields from filter tipped cigarettes illustrating
the invention % % Weight % Sodium Weight % % % PGA Puff TPM
Glycerol (g) Perlite Alginate (g) Carbon Glycerol Chalk Binder
Number (mg) (mg) 0.6035 90 10 0.5865 12 0 78 10 DNB 0.0 0 0.4025 90
10 0.7255 15 0 75 10 5 0.0 0 0.4535 90 10 0.7291 20 0 70 10 10 0.2
0 0.4774 90 10 0.6896 30 0 60 10 6 0.0 0 0.3812 90 10 0.5973 50 0
40 10 5 0.1 0 6.6001 90 10 0.6847 8 5 77 10 DNB 0.0 0 0.6344 90 10
0.7186 12 6 72 10 7 4.3 2 0.6555 90 10 0.7691 15 6 69 10 7 3.3 1
0.6777 90 10 0.6818 20 6 64 10 8 3.0 <1 0.4730 90 10 0.7691 30 6
54 10 6 2.2 <1 0.6312 90 10 0.6530 40 6 44 10 8 1.9 <1 0.5103
90 10 0.4808 12 8 70 10 9 1.3 <1 0.5845 90 10 0.6990 4 10 76 10
DNB 0 0 0.6219 90 10 0.7192 8 10 72 10 6 3.8 2 0.5060 90 10 0.6780
10 10 70 10 DNB 0 0 0.4872 90 10 0.6916 11 10 69 10 5 4.3 3 0.6035
90 10 0.5865 12 10 68 10 DNB 0 0 0.5665 90 10 0.6215 9 15 66 10 8
5.7 2 0.4838 90 10 0.7133 10 15.5 64.5 10 7 5.4 3 0.5161 90 10
0.7092 11 15 64 10 6 7.5 3 0.6103 90 10 0.6443 8 21.5 60.5 10 6 6.4
3 0.4461 90 10 0.7446 8 26 56 10 6 12.7 6
* * * * *