BACKGROUND OF THE INVENTION
[0001] The present invention relates to a smoking article which produces a- aerosol that
resembles tobacco smoke, and which obtains no more than a minimal amount of incomplete
combustion or pyrolysis products.
[0002] Many smoking articles have been proposed through the years, especially over the last
20 to 30 years, but none of these products has ever realized any commercial success.
[0003] Despite decades of interest and effort, there is still no smoking article on the
market which provides the benefits and advantages associated with conventional cigarette
smoking, without delivering consideratle quantities of incomplete combustion and pyrolysis
products.
SUMMARY OF THE INVENTION
[0004] The present invention relates to a smoking article which is capable of producing
substantial quantities of aerosol, both initially and over the useful life of the
product, without significant thermal degradation of the aerosol former and without
the presence of substantial pyrolysis or incomplete combustion products, and preferably
without substantial quantities of sidestream smoke. Smoking articles in accordance
with the present invention are capable of providing the user with the sensations and
benefits of cigarette smoking, without burning tobacco.
[0005] These and other advantages are obtained by providing an elongated, cigarette type
smoking article which utilizes a combustible fuel element, preferably of a carbonaceous
material, in conjunction with a physically separate aerosol generating means which
is in conductive heat exchange relationship with the fuel element. Upon lighting,
the fuel element generates heat which is used to volatilize the aerosol forming substance
or substances in the aerosol generating means. These volatile materials are then drawn
toward the mouth end, especially during puffing, and into the user's mouth, akin to
the smoke of a conventional cigarette.
[0006] Preferably, the fuel element is less than about 30 mm in length, more preferably
less than 15 mm in length, has a density of at least 0.5 g/cc, and is provided with
one or more longitudinal passages. Advantageously, the aerosol generating means includes
a heat stable substrate including one or more aerosol forming substances. Preferably,
the heat exchange relationship between the fuel and the aerosol generator is achieved
by providing a heat conducting member, such as a metal foil, which efficiently conducts
or transfers heat from the burning fuel element to the aerosol generating means. This
heat conducting member preferably contacts the fuel element and the aerosol generating
means around at least a portion of their peripheral surfaces. In addition, at least
a part of the fuel element is preferably provided with a peripheral insulating member,
such as a jacket of insulating fibers, the jacket being preferably resilient and at
least 0.5 mm thick, which reduces radial heat loss and assists in retaining and directing
heat from the fuel element toward the aerosol generating means. The insulating member
preferably overwraps at least part of the fuel element, and advantageously at least
part of the aerosol generating means.
[0007] Because the preferred fuel element is relatively short, the hot, burning fire cone
is always close to the aerosol generating means, which maximizes heat transfer thereto
and maximizes the resultant production of aerosol, especially in embodiments which
are provided with a heat conducting member. The preferred use of a relatively short,
low mass substrate or carrier as the aerosol generating means, in close proximity
to the short fuel element, also increases aerosol production by minimizing the heat
sink effect of the substrate. Because the aerosol forming substance is physically
separate from the fuel element, it is exposed to substantially lower temperatures
than are present in the burning fire cone, thereby minimizing the possibility of thermal
degradation of the aerosol former. Moreover, the especially preferred use of a carbonaceous
fuel element which is substantially free of volatile organic material eliminates the
presence of substantial pyrolysis or incomplete combustion products and eliminates
the generation of substantial sidestream smoke.
[0008] The smoking article of the present invention normally is provided with a mouthend
piece including means, such as a longitudinal passage, for delivering the volatile
material produced by the aerosol generating means to the user. Advantageously, the
article has the same overall dimensions as a conventional cigarette, and as a result,
the mouthend piece and the aerosol delivery means usually extend over more than half
the length of the article. Alternatively, the fuel element and the aerosol generating
means may be produced without a built-in mouthend piece or aerosol delivery means,
for use with a separate, disposable or reusable mouthend piece.
[0009] The smoking article of the present invention also may include a charge or plug of
tobacco which may be used to add a tobacco flavor to the aerosol. Preferably, the
tobacco is placed at the mouth end of the aerosol generating means, or it may be mixed
with the carrier for the aerosol forming substance. Flavoring agents also may be incorporated
into the article to flavor the aerosol delivered to the user.
[0010] Preferred embodiments of the invention are capable of delivering at least 0.6 mg
of aerosol, measured as wet total particulate matter, in the first 3 puffs, when smoked
under FTC smoking conditions. (FTC smoking conditions consist of two seconds of puffing
(35 ml total volume) separated by 58 seconds of smolder). More preferred embodiments
of the invention are capable of delivering 1.5 mg or more of aerosol in the first
3 puffs. Most preferably, embodiments of the invention are capable of delivering 3
mg or more of aerosol in the first 3 puffs when smoked under FTC smoking conditions.
Moreover, preferred embodiments of the invention deliver an average of at least about
0.8 mg of wet total particulate matter per puff for at least about 6 puffs, preferably
at least about 10 puffs, under FTC smoking conditions.
[0011] The smoking article of the present invention also is capable of providing an aerosol
which is chemically simple, consisting essentially of oxides of carbon, air, water,
and the aerosol which carries any desired flavorants or other desired volatile materials,
and trace amounts of other materials. The aerosol preferably has no significant mutagenic
activity according to the Ames test discussed hereinafter. In addition, the article
may be made virtually ashless so that the user does not have to remove any ash during
use.
[0012] As used herein, and only for the purposes of this application, "aerosol" is defined
to include vapors, gases, particles, and the like, both visible and invisible, and
especially those components perceived by the user to be "smoke-like," generated by
action of the heat from the burning fuel element upon substances contained within
the aerosol generating means, or elsewhere in the article. As so defined, the term
"aerosol" also includes volatile flavoring agents and/or pharmacologically or physiologically
active agents, irrespective of whether they produce a visible aerosol.
[0013] As used herein, the phrase "conductive heat exchange relationship" is defined as
a physical arrangement of the aerosol generating means and the fuel element whereby
heat is transferred by conduction from the burning fuel element to the aerosol generating
means substantially throughout the burning period of the fuel element. Conductive
heat exchange relationships can be achieved by locating the aerosol generating means
in contact with the fuel element and in close proximity to the burning portion of
the fuel element, and/or by utilizing a conductive member to carry heat from the burning
fuel to the aerosol generating means. Preferably both methods of providing conductive
heat transfer are used.
[0014] As used herein, the term "carbonaceous" means primarily comprising carbon.
[0015] As used herein, the term "insulating means" applies to all materials which act primarily
as insulators. Preferably, these materials do not burn during use, but they may include
slow burning carbons and like materials, as well as materials which fuse during use,
such as low temperature grades of glass fibers. The insulators have a thermal conductivity
in g-cal/(sec) (cm
2)(
oC/cm), of less than about 0.05, preferably less than about 0.02, most preferably less
than about 0.005. See, Hackh's Chemical Dictionary, 34 (4th ed., 1969) and Lange's
Handbook of Chemistry, 10, 272-274 (llth ed., 1973).
[0016] The smoking article of the present invention is described in greater detail in the
accompanying drawings and in the detailed description of the invention which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
Figures 1 through 9 are longitudinal views of various embodiments of the invention;
Figure 1A is a sectional view of the embodiment of Figure 1, taken along lines lA-lA
in Figure 1;
Figure 2A is a longitudinal view of a modified, tapered fuel element of the-embodiment
of Figure 2;
Figure 3A is a sectional view of the embodiment of Figure 3, taken along lines 3A-3A
in Figure 3; and
Figure 10 depicts the average peak temperature profile of the smoking article of Example
5 during use.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The embodiment of the invention illustrated in Figure 1, which preferably has the
diameter of a conventional cigarette, includes a short, combustible carbonaceous fuel
element 10, an abutting aerosol generating means 12, and a foil lined paper tube 14,
which forms the mouthend piece 15 of the article. In this embodiment, fuel element
10 is a "blowpipe" charcoal, i.e. carbonized wood, which is provided with five longitudinally
extending holes 16. See Figure lA. The fuel element 10, which is about 20 mm long,
optionally may be wrapped with cigarette paper to improve lighting of the charcoal
fuel. This paper may be treated with known burn additives.
[0019] Aerosol generating means 12 includes a plurality of glass beads 20 coated with an
aerosol forming substance or substances, such as glycerin. The glass beads are held
in place by a porous disc 22, which may be made of cellulose acetate. This disc may
be provided with a series of peripheral grooves 24 which provide passages between
the disc and the foil lined tube 14.
[0020] The foil lined paper tube 14, which forms the mouthend piece of the article, surrounds
aerosol generating means 12 and the rear, non-lighting end of fuel element 1C. The
tube also forms an aerosol delivery passage 26 between the aerosol generating means
12 and mouth end 15 of the article.
[0021] The presence of foil lined tube 14, which couples the nonlighting end of fuel 10
to aerosol generator 12, also increases heat transfer to the aerosol generator. The
foil also helps to extinguish the fire cone. When only a small amount of the unburned
fuel remains, heat loss through the foil acts as a heat sink which helps to extinguish
the fire cone.
[0022] The foil used in this article is typically an aluminum foil of 0.35 mils (0.0089
mm) in thickness, but the thickness and/or the type of metal employed may be varied
tc achieve any desired degree of heat transfer. Other types of heat conducting members
such as Grafoil, available from Union Carbide, also may be employed.
[0023] The article illustrated in Figure 1 also includes an -optional mass or plug of tobacco
28 to contribute flavor to the aerosol. This tobacco charge 28 may be placed at the
mouth end of disc 22, as shown in Figure 1, or it may be placed between glass beads
20 and disc 22. It also may be placed in passage 26 at a location spaced from aerosol
generator 12.
[0024] In the embodiment shown in Figure 2, the short fuel element 10 is a pressed carbon
rod or plug, about 20 mm long, which is provided with an axial hole 16. Alternatively,
the fuel may be formed from carbonized fibers and preferably also provided with an
axial passageway corresponding to hole 16. In this embodiment, aerosol generating
means 12 includes a thermally stable conductive carbonaceous substrate 30, such as
a plug of porous carbon, which is impregnated with an aerosol forming substance or
substances. This substrate may be provided with an optional axial passageway 32, as
is shown in Figure 2. This embodiment also includes a mass of tobacco 28 which is
preferably placed at the mouth end of substrate 30. For appearance sake, this article
also includes an optional high porosity cellulose acetate filter 34, which may be
provided with peripheral grooves 36 to provide passages for the aerosol forming substance
between filter 34 and foil tube 14. Optionally, as shown in Figure 2A, the lighting
end 11 of the fuel element may be tapered to improve lightability.
[0025] The embodiment of the invention illustrated in Figure 3, includes a sport combustible
carbonaceous fuel element 10, connected to aerosol generating means 12 by a heat conductive
rod 99 and by a foil lined paper tube 14, which also leads to the mouth end 15-of
the article. In this embodiment, fuel element 10 may be blowpipe charcoal or a pressed
or extruded carbon rod or plug or other carbonaceous fuel source.
[0026] Aerosol generating means 12 includes a thermally stable carbonaceous substrate 30,
such as a plug of porous carbon, which is impregnated with an aerosol forming substance
or substances. This embodiment includes a void space 97 between the fuel element 10
and the substrate 30. The portion of the foil lined tube 14 surrounding this void
space includes a plurality of peripheral holes 100 which permit sufficient air to
enter the void space to provide appropriate pressure drop.
[0027] As shown in Figures 3 and 3A, the heat conducting means includes a conductive rod
99 and the foil lined tube 14. The rod 99, preferably formed of aluminum, has at least
one, preferably from 2 to 5, peripheral grooves 96 therein, to allow air passage through
the substrate. The article of Figure 3 has the advantage that the air introduced into
the void space 97 contains less carbon oxidation products because it is not drawn
through the burning fuel.
[0028] The embodiment illustrated in Figure 4 includes a fibrous carbon fuel element 10,
such as carbonized cotton or rayon. The fuel element includes a single axial hole
16. The substrate 38 of the aerosol generator is a granular, thermally stable carbon.
A mass of tobacco 28 is located immediately behind the substrate. This article is
provided with a cellulose acetate tube ,40, in place of the foil lined tube of previous
embodiments. This tube 40 includes an annular section 42 of cellulose acetate tow
surrounding an optional plastic, e.g., polypropylene tube 44. At the mouth end 15
of this element there is a low efficiency cellulose acetate filter plug 45. The entire
length of the article is wrapped in cigarette-type paper 46. A cork or white ink coating
48 may be used on the mouth end to simulate tipping. A foil strip 50 is located on
the inside'of the paper, toward the fuel end of the article. This strip preferably
extends from the rear portion of the fuel element to the mouth end of the tobacco
charge 28. It may be integral with the paper or it may be a separate piece applied
before the paper overwrap.
[0029] The embodiment of Figure 5 is similar to that of Figure 4. In this embodiment, the
aerosol generating means 12 is formed by an aluminum macrocapsule 52 which is filled
with a granular substrate or, as shown in the drawing, a mixture of a granular substrate
54, and tobacco 56. The macrocapsule 52 is crimped at its ends 58, 60 to enclose the
material and to inhibit migration of the aerosol former. The crimped end 58, at the
fuel end, preferably abuts the rear end of the fuel element to provide for conductive
heat transfer. A void space 62 formed by end 58 also helps to inhibit migration of
the aerosol former to the fuel. Longitudinal passageways 59 and 61 are provided to
permit the passage of air and the aerosol forming substance. Macrocapsule 52 and fuel
element 10 may be united by a conventional cigarette paper 47, as illustrated in the
drawing, by a perforated ceramic paper, or a foil strip. If cigarette paper is used,
a strip 64 near the rear end of the fuel should be printed or treated with sodium
silicate or other known materials which cause the paper to extinguish. The entire
length of the article is overwrapped with conventional cigarette paper 46.
[0030] Figure 6 illustrates another embodiment having a pressed carbon fuel plug 10. In
this embodiment, the fuel element has a tapered lighting end 11 for easier lighting
and a tapered rear end 9 for easy fitting into a tubular foil wrapper 66. Abutting
the rear end of the fuel element is an aluminum disc 68 with a center hole 70. A second,
optional aluminum disc 72 with hole 74 is located at the mouth end of the aerosol
generator 12. In between is a zone 76 of a particulate substrate and a zone 78 of
tobacco. The foil wrapper 66 in which the fuel element is mounted extends back beyond
the second aluminum disc 72. This embodiment also includes a hollow cellulose acetate
rod 42 with an internal polypropylene tube 44, and a cellulose acetate filter plug
45. The entire length of the article is preferably wrapped with cigarette paper 46.
[0031] The embodiment shown in Figure 7 illustrates the use of a substrate 80 embedded within
a large cavity 82 in fuel element 10. In this embodiment, the fuel element preferably
is formed from an extruded carbon, and the substrate 80 usually is a relatively rigid,
porous material. The entire length of the article is wrapped with conventional cigarette
paper 46. This embodiment may also include a foil strip 84 to couple fuel element
10 to the cellulose acetate tube 40 and to help extinguish the fuel.
[0032] The embodiments shown in Figures 8 and 9 include a nonburning insulating jacket 86
around fuel element 10 to insulate and concentrate the heat in the fuel element. These
embodiments also help to reduce any fire causing potential of the burning fire cone.
[0033] In the embodiment shown in Figure 8, both fuel element 10 and substrate 30 are located
within an annular jacket or tube 86 of insulating fibers, such as ceramic (e.g., glass)
fibers. Nonburning carbon or graphite fibers may be used in place of ceramic fibers.
Fuel element 10 is preferably an extruded carbon plug having a hole 16. In the illustrated
embodiment, the lighting end 11 extends slightly beyond the edge of jacket 86 for
ease of lighting. Substrate 30 is a solid porous carbon material, although other types
of substrates may be used. The substrate and the rear portion of the fuel element
are surrounded by a piece of aluminum foil 87. As illustrated, this jacketed fuel/substrate
unit is coupled to a mouthend piece, such as the elongated cellulose acetate tube
40 shown in the drawing, with an overwrap of conventional cigarette paper 46. The
jacket 86 extends to the mouth end of substrate 30, but may replace cellulose acetate
rod 42.
[0034] In the embodiment shown in Figure 9, an aluminum macrocapsule 52 of the type shown
in Figure 5 is used to enclose a granular substrate 54 and tobacco 56. This macrocapsule
is preferably positioned entirely within the insulator jacket 86. In addition, the
lighting end 11 of fuel element 10 does not protrude beyond the forward end of jacket
86. Preferably, the macrocapsule and the rear portion of the fuel element are surrounded
by a piece of aluminum foil in a manner similar to that shown in Figure 8.
[0035] Alternatively, the aluminum foil 52 which surrounds the substrate is only crimped
at the mouth end. In such an embodiment, the rear end of the fuel element may be inserted
into one end of the foil and a polypropylene tube may be fitted over or placed in
abutment with the mouth end of the foil. The entire assembly is overwrapped with fiberglass
to a diameter of a conventional cigarette.
[0036] Upon lighting any of the aforesaid embodiments, the fuel element burns, generating
the heat used to volatilize the aerosol forming substance or substances present in
the aerosol generating means. These volatile materials are then drawn toward the mouthend,
especially during puffing, and into the user's mouth, akin to the smoke of a conventional
cigarette.
[0037] Because the fuel element preferably is relatively short, the hot, burning fire cone
is always close to the aerosol generating body, which maximizes heat transfer to the
aerosol generating means, and resultant production of aerosol, especially when the
preferred heat conducting member is used. In addition, the preferred insulating member
tends to confine, direct, and concentrate the heat toward the central core of the
article, thereby increasing the heat transferred to the aerosol forming substance.
[0038] Because the aerosol forming substance is physically separate from the fuel element,
it is exposed to substantially lower temperatures than are present in the burning
fire cone. This minimizes the possibility of thermal degradation of the aerosol former.
This also results in aerosol production during puffing, but little or no aerosol production
during smolder. In addition, the use of the preferred carbonaceous fuel elements and
a physically separate aerosol generating means eliminates the presence of substantial
pyrolysis or incomplete combustion products and avoids the production of substantial
sidestream smoke.
[0039] Because of the small size and burning characteristics of the preferred carbonaceous
fuel element employed in the present invention, the fuel element usually begins burning
over substantially all of its exposed length within a few puffs. Thus, the portion
of the fuel element adjacent to the aerosol generating means becomes hot quickly,
which significantly increases heat transfer to the aerosol generating means, especially
during the early and middle puffs. Because the preferred fuel element is short, there
is never a long section of nonburning fuel to act as a heat sink, as was common in
previous thermal aerosol articles. Heat transfer, and therefor aerosol delivery, also
is enhanced by the use of holes through the fuel, which draw hot air to the aerosol
generator, especially during puffing.
[0040] In the preferred embodiments of the invention, the short carbonaceous fuel element,
heat conducting member, insulating means, and passages in the fuel cooperate with
the aerosol generator to provide a system which is capable of producing substantial
quantities of aerosol, on virtually every puff. The close proximity of the fire cone
to the aerosol generator after a few puffs, together with the insulating means, results
in high heat delivery both during puffing and during the relatively long period of
smolder between puffs.
[0041] While not wishing to be bound by theory, it is believed that the aerosol generating
means is maintained at a relatively high temperature between puffs, and that the additional
heat delivered during puffs, which is significantly increased by the hole or holes
in the fuel element, is primarily utilized to vaporize the aerosol forming substance.
This increased heat transfer makes more efficient use of the available fuel energy,
reduces the amount of fuel needed, and helps deliver early aerosol. Further, the conductive
heat transfer utilized in the present invention is believed to reduce the carbon fuel
combustion temperature which, it is further believed, reduces the CO/C0
2 ratio in the combustion products produced by the fuel. See, e.g., G. Hagg, General
Inorganic Chemistry, at p. 592 (John Wiley & Sons, 1969) .
[0042] Furthermore, by the appropriate selection of the fuel element, the insulating jacket,
the paper overwrap, and the heat conducting means, it is possible to control the burn
properties of the fuel source. This provides opportunities for control of heat transfer
to the aerosol generator, which in turn, alters the number of puffs and/or the amount
of aerosol delivered to the user.
[0043] In general, the combustible fuel elements which may be employed in practicing the
invention are less than about 30 mm long. Advantageously the fuel element is about
20 mm or less, preferably about 15 mm or less in length. Advantageously, the diameter
of the fuel element is between about 3 and 8 mm, preferably about 4 to 5 mm. The density
of the fuel elements employed herein has ranged from about 0.5 g/cc to about 1.5 g/cc.
Preferably, the density is greater than 0.7 g/cc., more preferably greater than 0.8
g/cc. Preferably, the fuel is provided with one or more longitudinally extending holes,
such as holes 11 in Figures 1 through 5. These holes provide porosity and increase
early heat transfer to the substrate by increasing the amount of hot gases which reach
the substrate.
[0044] The preferred fuel elements employed herein are primarily formed of a carbonaceous
material. Carbonaceous fuel elements are preferably from about 5 to 15 mm, more preferably,
from about 8 to 12 mm in length. Carbonaceous fuel elements having these characteristics
are sufficient to provide fuel for at least about 7 to 10 puffs, the normal number
of puffs generally obtained by smoking a conventional cigarette under FTC conditions.
[0045] Preferably, the carbon content of such a fuel element is at least 60 - 70%, most
preferably at least about 80% or more by weight. Excellent results have been achieved
with fuel elements having a carbon content of above above about 85% by weight. High
carbon content fuels are preferred because they produce minimal pyrolysis and incomplete
combustion products, little or no visible sidestream smoke, and minimal ash and have
high heat capacity. However, lower carbon content fuel elements, e.g., about 50 -
65 weight percent, are within the scope of this invention, especially where a nonburning
inert filler is used.
[0046] Also, while not preferred, other fuel materials may be employed, such as tobacco,
tobacco substitutes and the like, provided that they they generate and conduct sufficient
heat to the aerosol generating means to produce the desired level of aerosol from
the aerosol forming material, as discussed above. The density of the fuel used should
be above about 0.5g/cc., preferably above about 0.7 g/cc., which is higher than the
densities normally used in conventional smoking articles. Where such other materials
are used, it is much preferred to include carbon in the fuel, preferably in amounts
of at least about 20 - 40% by weight, more preferably at least about 50% by weight,
and most preferably at least about 65 -70% by weight, the balance being being the
other fuel components, including any binder, burn modifiers, moisture, etc.
[0047] The carbonaceous materials used in or as the preferred fuel may be derived from virtually
any of the numerous carbon sources known to those skilled in the art. Preferably,
the carbonaceous material is obtained by the pyrolysis or carbonization of cellulosic
materials, such as wood, cotton, rayon, tobacco, coconut, paper, and the like, although
carbonaceous materials from other sources may be used.
[0048] In most instances, the carbonaceous fuel element should be capable of being ignited
by a conventional cigarette lighter without the use of an oxidizing agent. Burning
characteristics of this type may generally be obtained from a cellulosic material
which has been pyrolyzed at temperatures between about 400
0c to about 1000°C, preferably between about 500°C to about 950
0C, in an inert atmosphere or under a vacuum. The pyrolysis time is not believed to
be critical, as long as the temperature at the center of the pyrolyzed mass has reached
the aforesaid temperature range for at least a few minutes. However, a slow pyrolysis,
employing gradually increasing temperatures over several hours is believed to produce
a more uniform material with a higher carbon yield.
[0049] While undesirable in most cases, carbonaceous fuel elements which require the addition
of an oxidizing agent to render them ignitable by a cigarette lighter are within the
scope of this invention, as are carbonaceous materials which require the use of a
glow retardant or other type of combustion modifying agent. Such combustion modifying
agents are disclosed in many patents and publications and are known to those of ordinary
skill in the art.
[0050] The most preferred carbonaceous fuel elements used in practicing the invention are
substantially free of volatile organic material. By that, it is meant that the fuel
element is not purposely impregnated or mixed with substantial amounts of volatile
organic materials, such as volatile aerosol forming or flavoring agents, which could
degrade in the burning fuel. However, small amounts of water, which are naturally
adsorbed by the fuel, may be present therein. Similarly, small amounts of aerosol
forming substances may migrate from the aerosol generating means and thus may also
be present in the fuel element.
[0051] A preferred carbonaceous fuel element is a pressed or extruded carbon mass prepared
from carbon and a binder, by conventional pressure forming or extrusion techniques.
A preferred activated carbon for such a fuel element is PCB-G, and a preferred non-activated
carbon is PXC, both available from Calgon Carbon Corporation, Pittsburgh, PA. Other
preferred carbons for pressure forming and/or extrusion are prepared from pyrolyzed
cotton or pyrolyzed papers.
[0052] The binders which may be used in preparing such a fuel element are well known in
the art. A preferred binder is sodium carboxymethylcellulose (SCMC) which may be used
alone, which is preferred, or in conjunction with materials such as sodium chloride,
vermiculite, bentonite, calcium carbonate, and the like. Other useful binders include
gums, such as guar gum, and other cellulose derivatives, such as methylcellulose and
carboxymethylcellulose (CMC).
[0053] A wide range of binder concentrations can be utilized. Preferably, the amount of
binder is limited to minimize contribution of the binder to undesirable combustion
products. On the other hand, sufficient binder must be included to hold the fuel element
together during manufacture and use. The amount used will thus depend on the cohesiveness
of the carbon in the fuel element.
[0054] If desired, the aforesaid fuel elements may be pyrolyzed after formation, for example,
to about 650
oC for two hours, to convert the binder to carbon thereby forming a virtually 100%
carbon fuel element.
[0055] The fuel elements employed in the present invention also may contain one or more
additives to improve burning, such as up to about 5 weight percent sodium chloride
to improve smoldering characteristics and as a glow retardant. Also, up to about 5,
preferably 1 to 2, weight percent of potassium carbonate may be included to improve
lightability. Additives to improve physical characteristics, such as clays like kaolins,
serpentines, attapulgites, and the like also may be used.
[0056] Another carbonaceous fuel element is a carbon fiber fuel, which may be prepared by
carbonizing a fibrous precursor, such as cotton, rayon, paper, polyacrylonitile, and
the like. Generally, pyrolysis at from about 650°C to 1000°, preferably at about 950°,
for about 30 minutes, in an inert atmosphere or vacuum, is sufficient to produce a
suitable carbon fiber with good burning characteristics. Combustion modifying additives
also may be added to these fibrous fuels.
[0057] The aerosol generating means used in practicing the invention is physically separate
from the fuel element. By physically separate it is meant that the substrate, container
or chamber which contains the aerosol forming materials is not mixed with, or a part
of, the burning fuel element. As noted previously, this arrangement helps reduce or
eliminate thermal degradation of the aerosol forming substance and the presence of
sidestream smoke. While not a part of the fuel, the aerosol generating means is in
a conductive heat exchange relationship with the fuel element, and preferably abuts
or is adjacent to the fuel element.
[0058] Preferably, the aerosol generating means includes one or more thermally stable materials
which carry one or more aerosol forming substances. As used herein, a thermally stable
material is one capable of withstanding the high temperatures, e.g., 400
0C - 600
0C, which exist near the fuel without decomposition or burning. The use of such material
is believed to help maintain the simple "smoke" chemistry of the aerosol, as evidenced
by the lack of Ames activity in the preferred embodiments. While not preferred, other
aerosol generating means, such as heat rupturable microcapsules, or solid aerosol
forming substances, are within the scope of the invention, provided they are capable
of releasing sufficient aerosol forming vapors to satisfactorily resemble tobacco
smoke.
[0059] Thermally stable materials which may be used as a substrate or carrier for the aerosol
forming substance are well known to those skilled in the art. Useful substrates should
be porous and must be capable of retaining an aerosol forming compound when not in
use and capable of releasing a potential aerosol forming vapor upon heating by the
fuel element.
[0060] Useful thermally stable materials include thermally stable adsorbent carbons, such
as porous grade carbons, graphite, activated, or nonactivated carbons, and the like.
Other suitable materials include inorganic solids such as ceramics, glass, alumina,
vermiculite, clays such as bentonite, and the like. The currently preferred substrate
materials are carbon felts, fibers, and mats, activated carbons, and porous carbons
such as PC-25 and P
G-60 available from Union Carbide, as well as SGL carbon available from Calgon.
[0061] Depending upon the particular aerosol generating means employed herein, the composition
and configuration thereof may generally be selected from particulate, fibrous, porous
blocks, solid blocks with one or more axially extending passageways therethrough,
and the like. Substrates, especially-particulates, may be placed within a container,
preferably formed from a metallic foil.
[0062] The aerosol generating means used in the invention is usually located no more than
about 60 mm, preferably no more than 30 mm, most preferably no more than 15 mm from
the lighting end of the fuel element. The aerosol generator may vary in length from
about 2 mm to about 60 mm, preferably from about 5 mm to 40 mm, and most preferably
from about 20 mm to 35 mm. If a non-particulate substrate is used, it may be provided
with one or more holes, to increase the surface area of the substrate, and to increase
air flow and heat transfer.
[0063] The aerosol forming substance or substances used in the invention must be capable
of forming an aerosol at the temperatures present in the aerosol generating means
when heated by the burning fuel element. Such substances preferably will be composed
of carbon, hydrogen and oxygen, but they may include other materials. The aerosol
forming substances can be in solid, semisolid, or liquid form. The boiling point of
the substance and/or the mixture of substances can range up to about 500
0C.- Substances having these characteristics include polyhydric alcohols, such as glycerin
and propylene glycol, as well as aliphatic esters of mono-, di-, or poly-carboxylic
acids, such as methyl stearate, dodecandioate, dimethyl tetradodecandioate, and others.
[0064] Preferably, the aerosol forming substances will include a mixture of a high boiling,
low vapor pressure substance and a low boiling, high vapor pressure substance. Thus,
on early puffs, the low boiling substance will provide most of the initial aerosol,
while, when the temperature in the aerosol generator increases, the high boiling substance
will provide most of the aerosol.
[0065] The preferred aerosol forming substances are polyhydric alcohols, or mixtures of
polyhydric alcohols. Especially preferred aerosol formers are selected from glycerin,
propylene glycol, triethylene glycol, or mixtures thereof.
[0066] The aerosol forming substance may be dispersed on or within the aerosol generating
means in a concentration sufficient to permeate or coat the substrate, carrier, or
container. For example, the aerosol forming substance may be applied full strength
or in a dilute solution by dipping, spraying, vapor deposition, or similar techniques.
Solid aerosol forming components may be admixed with the substrate and distributed
evenly throughout prior to formation.
[0067] While the loading of the aerosol forming substance will vary from carrier to carrier
and from aerosol forming substance to aerosol forming substance, the amount of liquid
aerosol forming substances may generally vary from about 20 mg to about 120 mg, preferably
from about 35 mg to about 85 mg, and most preferably from about 45 mg to about 65
mg. As much as possible of the aerosol former carried on the aerosol generating means
should be delivered to the user as WTPM. Preferably, above about 2 weight percent,
more preferably above about, 15 weight percent, and most preferably above about 20
weight percent of the aerosol former carried on the aerosol generating means is delivered
to the user as WTPM.
[0068] The aerosol generating means also may include one or more volatile flavoring agents,
such as menthol, vanillin, artificial coffee, tobacco extracts, nicotine, caffeine,
liquors, and other agents which impart flavor to the aerosol. It also may include
any other desirable volatile solid or liquid materials.
[0069] As previously pointed out, the smoking article of the present invention also may
include a charge or plug of tobacco which may be used to add a tobacco flavor to the
aerosol. Preferably, the tobacco is placed at the mouth end of the aerosol generating
means, or it may be mixed with the carrier for the aerosol forming substance. Flavoring
agents also may be incorporated into the article to flavor the aerosol delivered to
the user.
[0070] If a charge of tobacco is employed, hot vapors are swept through the bed of tobacco
to extract and vaporize the volatile components in the tobacco, without the need for
tobacco combustion. Thus the user of this smoking article receives an aerosol which
contains the qualities and flavors of natural tobacco without the combustion products
produced by a conventional cigarette.
[0071] Alternatively, these optional agents may be placed between the aerosol generating
means and the mouthend, such as in a separate substrate or chamber in the passage
which leads from the aerosol generating means to the mouthend, or in the optional
tobacco charge. If desired, these volatile agents may be used in lieu of part, or
all, of the aerosol forming substance, so that the article delivers a nonaerosol flavor
or other material to the user.
[0072] Articles of the type disclosed herein may be used or may be modified for use as drug
delivery articles, for delivery of volatile pharmacologically or physiologically active
materials such as ephedrine, metaproterenol, terbutaline or the like.
[0073] The heat conducting member preferably employed in practicing this invention is typically
a metallic foil, such as aluminum foil, varying in thickness from less than about
0.01 mm to about 0.1 mm, or more. The thickness and/or the type of conducting material
may be varied to achieve virtually any desired degree of heat transfer. As shown in
the illustrated embodiments, the heat conducting member preferably contacts or overlaps
a portion of the fuel element and the aerosol generating means, and may form the container
which encloses the aerosol forming substance.
[0074] Insulating members which may be used in accordance with the present invention generally
comprise inorganic or organic fibers such as those made out of glass, alumina, silica,
vitreous materials, mineral wool, carbons, silicons, boron, organic polymers, cellulosics,
and the like, including mixtures of these materials. Nonfibrous insulating materials,
such as silica aerogel, pearlite, glass, and the like, formed in mats, strips or other
shapes, may also be used. Preferred insulating members are resilient, to help simulate
the feel of a conventional cigarette. These materials act primarily as an insulating
jacket, retaining and directing a significant portion of the heat formed by the burning
fuel element to the aerosol generating means. Because the insulating jacket becomes
hot adjacent to the burning fuel element, to a limited extent, it also may conduct
heat toward the aerosol generating means.
[0075] Currently preferred insulating materials include ceramic fibers, such as glass fibers.
Two especially preferred glass fibers are available from the Manning Paper Company
of Troy, New York, under the designations, Manniglas 1000 and Manniglas 1200. Generally
the insulating fiber is wrapped over at least a portion of the fuel element and any
other desired portion of the article, to a final diameter of from about 7 to 8 mm.
Thus, the preferred thickness of the insulating layer is from about 0.5 mm to 2.5
mm, preferably, from about 1 mm to 2 mm. When possible, glass fiber materials having
a low softening point, e.g., below about 650
0C, are preferred.
[0076] When the insulating means is fibrous, there is preferably employed a barrier means
at the mouth end of the article. One such barrier means comprises an annular member
of high density cellulose acetate tow which abutts the fibrous insulating means and
which is sealed, preferably at the mouth-end, with, for example, glue, to block air
flow through the tow.
[0077] In most embodiments of the invention, the fuel/aerosol generating means combination
will be attached to a mouthend piece, such as a foil lined paper or cellulose acetate/plastic
tubes illustrated in the figures, although a mouthend piece may be provided separately,
e.g., in the form of a cigarette holder. This element of the article provides the
passageway which channels the vaporized aerosol forming substance into the mouth of
the user. Due to its length, preferably about 50 to 60 mm or more, it also keeps the
hot fire cone away from the mouth and fingers of the user.
[0078] Suitable mouthend pieces should be inert with respect to the aerosol forming substances,
should have a water or liquid proof inner layer, should offer minimum aerosol loss
by condensation or filtration, and should be capable of withstanding the temperature
at the interface with the other elements of the article. Preferred mouthend pieces
include the foil lined tube of Figures 1 - 3 and the cellulose-acetate tube employed
in the embodiments of Figures 4 - 9. Other suitable mouthend pieces will be apparent
to those of ordinary skill in the art.
[0079] The mouthend pieces of the invention may include an optional "filter" tip, which
is used to give the article the appearance of the conventional filtered cigarette.
Such filters include low density cellulose acetate filters and hollow or baffled plastic
filters, such as those made of polypropylene. In addition, the entire length of article
or any portion thereof may be overwrapped with cigarette paper.
[0080] The aerosol produced by the preferred articles of the present invention is chemically
simple, consisting essentially of air, oxides of carbon, the aerosol which carries
any desired flavorants or other desired volatile materials, water, and trace amounts
of other materials. The wet total particulate matter (WTPM) produced by the preferred
articles of this invention has no mutagenic activity as measured by the Ames test,
i.e., there is no significant dose response relationship between the WTPM of the present
invention and the number of revertants occurring in standard test microorganisms exposed
to such products. According to the proponents of the Ames test, a significant dose
dependent response indicates the presence of mutagenic materials in the products tested.
See Ames et al., Mut. Res., 31:347-364 (1975) ; Nagas gt al., Mut. Res.. 42:335 (1977).
[0081] A further benefit from the preferred embodiments of the present invention is the
relative lack of ash produced during use in comparison to ash from a conventional
cigarette. As the preferred carbon fuel source is burned, it is essentially converted
to oxides of carbon, with relatively little ash generation, and thus there is no need
to dispose of ashes while using the article.
[0082] The smoking article of the present invention will be further illustrated with reference
to the following examples which aid in the understanding of the present invention,
but which are not to be construed as limitations thereof. All percentages reported
herein, unless otherwise specified, are percent by weight. All temperatures are expressed
in degrees Celsius and are uncorrected. In all instances, the smoking articles have
a diameter of about 7 to 8 mm, the diameter of a conventional cigarette.
Example 1
[0083] A smoking article was constructed in accordance with the embodiment of Figure 1.
The fuel element was a 25 mm long piece of blow pipe charcoal, with five 0.040 in.
(1.02 mm) longitudinal passageways made with a number 60 drill bit. The charcoal weighed
0.375 g. The fuel element was wrapped with conventional treated cigarette paper. The
substrate was 500 mg of glass beads (0.64 in. [1.63 mm) average diameter) having two
drops, approximately 50 mg, of glycerol coated on their surface. When packed into
the tube, this substrate was about 6.5 mm long. The foil lined tube consisted of a
0.35 mil (0.0089 mm) layer of aluminum foil inside a 4.25 mil (0.108 mm) layer of
white spirally wound paper. This tube surrounded the rear 5 mm of the fuel element.
A short (8 mm) piece of cellulose acetate with four grooves around the periphery was
used to hold the glass beads against the fuel source. An additional grooved cellulose
acetate filter piece of 8 mm length was inserted into the mouth end of the tube to
give the appearance of a conventional cigarette. The overall length of the article
was about 70 mm.
[0084] Models of this type delivered considerable aerosol on the lighting puff, reduced
amounts of aerosol on puffs 2 and 3, and good delivery of aerosol on puffs 4 through
9. Models of this type generally yielded about 5-7 mg of wet total particulate matter
(WTPM) when machine smoked under FTC smoking procedures of a 35 ml puff volume, a
two second puff duration, and a 60 second puff frequency.
Example 2
[0085] A. Four smoking articles were constructed with 10 mm long pressed carbon fuel elements
and glass bead substrates. The fuel elements were formed from 90% PC
B-G and 10% SCMC, at about 5000 pounds (2273 kg) of applied load with the tapered lighting
end illustrated in Figure 2A. A single 0.040 in (1.02 mm) hole was formed down the
center of each element. Three of the four fuel sources were wrapped with 8 mm wide
strips of conventional cigarette paper. The fuel elements were inserted about 2 mm
into 70 mm long sections of the foil lined tube described in Example 1. Glass beads,
coated with the amount of glycerol indicated in the following table, were inserted
into the open end of the foil lined tube and were held against the fuel element by
5 mm long foamed polypropylene filters having a series of longitudinally extending
peripheral grooves. A 5 mm long low efficiency cellulose acetate filter piece was
inserted into the mouth end of each article. These articles were machine smoked under
FTC smoking conditions and the wet total particulate matter (WTPM) was collected on
a series of Cambridge pads. The results of these experiments are reported in Table
I.

[0086] B. Three smoking articles similar to those described in Example 2A were constructed
with 20 mm long blowpipe charcoal fuel elements of the type described in Example 1.
These articles were machine smoked under FTC smoking conditions, and the WTPM was
collected on a series of Cambridge pads. The results of these tests are reported in
Table II.

Example 3
[0087] A. Pour smoking articles were constructed as shown in Figure 2 with a 10 mm pressed
carbon fuel element having the tapered lighting end illustrated in Figure 2A. The
fuel element was made from 90% PCB-G carbon and 10% SCMC, at about 5000 pounds (2273
kg) of applied load. A 0.040 in. (1.02 mm) hole was drilled down the center of the
element. The substrate for the aerosol former was cut and machined to shape from PC-25,
a porous carbon sold by Union Carbide Corporation, Danbury, CT. The substrate in each
article was about 2.5 mm long, and about 8 mm in diameter. It was loaded with an average
of about 27 mg of a 1:1 propylene glycol-glycerol mixture. The foil lined tube mouthend
piece, of the same type as used in Example 1, enclosed the rear 2 mm of the fuel element
and the substrate. A plug of Burley tobacco, about 100 mg was placed against the mouth
end of the substrate. A short, about 5-9 mm, baffled polypropylene filter piece was
placed in the mouth end of the foil lined tube. A 32 mm length of a cellulose acetate
filter with a hollow polypropylene tube in the core was placed between the tobacco
and the filter piece. The overall length of each article was about 78 mm.
[0088] B. Six additional articles were constructed substantially as in Example 3A, but the
substrate length was increased to 5 mm, and a 0.040 in (1.02 mm) hole was drilled
through the substrate. In addition, these articles did not have a cellulose acetate/polypropylene
tube. About 42 mg of the propylene glycol-glycerol mixture was applied to the substrate.
In addition, two plugs of Burley tobacco, about 100-150 mg each, were used. The first
was placed against the mouth end of the substrate, and the second one was placed against
the filter piece.
[0089] C. Four additional articles were constructed substantially as in Example 3A, except
that an approximately 100- mg plug of flue-cured' tobacco containing about six percent
by weight of diammonium monohydrogen phosphate was used in lieu of the plug of Burley
tobacco.
[0090] D. The smoking articles from Examples 3A-C were tested using the standard Ames Test.
See Ames, et al., Mut. Res., 31:347-364 (1975), as modified by Nagas et al., But.
Res., 42:335 (1977), and 113:173-215 (1983). The samples 3A and C were "smoked" on
a conventional cigarette smoking machine using the conditions of a 35 ml puff volume,
a two second puff duration, and a 30 second puff frequency, for ten puffs. The smoking
articles of Example 3B were smoked in the same manner except that a 60 second puff
frequency was used. Only one filter pad was used for each group of articles. This
afforded the following wet total particulate matter (WT
PM) for the indicated groups of articles:

[0091] The filter pad for each of the above examples containing the collected WTPM was shaken
for 30 minutes in DMSO to dissolve the WTPM. Each sample was then diluted to a concentration
of 1 mg/ml and used "as is" in the Ames assay. Using the procedure of Nagas et al.,
Mut. Res, 42:335-342 (1977), 1 mg/ml concentrations of WTPM were admixed with the
S-9 activating system, plus the standard Ames bacterial cells, and incubated at 37
0C for twenty minutes. The bacterial strain used in this Ames assay was Salmonella
typhimurium, TA 98, See Purchase et al., Nature, 264:624-627 (1976). Agar was then
added to the mixture, and plates were prepared. The agar plates were incubated for
two days at 37°C, and the resulting cultures were counted. Four plates were run for
each dilution and the standard deviations of the colonies were compared against a
pure DMSO control culture. As shown in Table III, there was no mutagenic activity
caused by the WTPM obtained from any of the smoking articles tested. This can be ascertained
by comparison of the mean number of revertants per plate with the mean number of revertants
obtained from the control (0 ug WTPM/Plate). For mutagenic samples, the mean number
of revertants per plate will increase with increasing doses.

Example 4
[0092] Five smoking articles were constructed as shown in Figure 2. Each article had a 10
mm pressed carbon fuel source as described in Example 3A. This fuel element was inserted
3 mm into one end of a 70 mm long aluminum foil lined tube of the type described in
Example 1. A 5 mm long carbon felt substrate, cut from rayon carbon felt sold by Fiber
Materials, Inc., was butted against the fuel source. This substrate was loaded with
an average of about 97 mg of a 1:1 mixture of glycerin and propylene glycol, about
3 mg of nicotine, and about 0.1 mg of a mixture of flavorants. A 5 mm long section
of blended tobacco was butted against the mouth end of the substrate. A 5 mm long
cellulose acetate filter piece was placed in the mouth end of the foil lined tube.
[0093] These articles were machine smoked under the FTC conditions. The aerosol from these
articles was collected on a single Cambridge pad (133.3 mg WTPM), diluted in DMSO
to a final concentration of 1 mg WTPM per ml and tested for Ames activity as described
in Example 3D using each of the following strains: Salmonella typhimurium TA 1535,
1537, 1538, 98, and 100. As shown in Table IV there was no mutagenic activity caused
by the WTPM collected from the articles tested.

Example 5
[0094] A smoking article was built as shown in Figure 2 with a 10 mm pressed carbon fuel
plug having the configuration shown in Figure 2A, but with no tobacco. The fuel element
was made from a mixture of 90% PCB-G activated carbon and 10% SCMC as a binder at
about 5000 pounds (2273 kg) of applied load. The fuel element was provided with a
0.040 in (1.02 mm) longitudinal passageway. The substrate was a 10 mm long porous
carbon plug made from Union Carbide's PC-25. It was provided with a 0.029 in. (0.74
mm) drilled axial hole, and was loaded with 40 mg of a (1:1) mixture of propylene
glycol and glycerol. The foil lined tube, as in Example 1, encircled the rear 2 mm
of the fuel element and formed the mouthend piece. The article did not have a filter
tip, but was overwrapped with conventional cigarette paper. The total length of the
article was 80 mm.
[0095] The average peak temperatures for this article are shown for both "puff" and "smolder"
in Figure 10. As shown, the temperature declines steadily between the rear end of
the fuel element and mouthend. This assures the user of no unpleasant burning sensation
when using a product of this invention.
Example 6
[0096] A smoking article was constructed in accordance with the embodiment of Figure 3.
The fuel element was a 19 mm long piece of blowpipe charcoal, with no longitudinal
passageways. Embedded 15 mm into the fuel element was a 1/8 in. (3.2 mm) diameter
aluminum rod, 28 mm in length. Four 9 mm x 0.025 in. (0.64 mm) peripheral grooves,
spaced 90° apart were cut into the portion of the aluminum rod which pierced the substrate.
The substrate was Union Carbide PC-25 carbon 8 mm in length. The grooves in the aluminum
rod extended about 0.5 mm beyond the end of the substrate toward the fuel. The substrate
was loaded with 150 mg of glycerol. The foil lined tube, which was the same as in
Example 1, enclosed a portion of the "rear of the fuel element. A gap was left between
the non-burning end of the fuel element and the substrate. A series of holes were
cut through the foil lined tube in this gap region to allow for air flow. A similar
smoking article was constructed with a pressed carbon fuel plug.
Example 7
[0097] A smoking article was constructed as shown in Figure 4 with a fuel source of carbonized
cotton fiber. Four slivers of cotton were tightly braided together with cotton string
to form a rope with a diameter of about 0.4 in. (10.2 mm). This material was placed
in a nitrogen atmosphere furnace which was heated to 950
0C. It took about 1 1/2 hours to reach that temperature, which was then held for 1/2
hour. A 16 mm piece was cut from this pyrolyzed material to be used as the fuel element.
A 2 mm axial hole 16 was made through the element with a probe. The fuel element was
inserted 2 mm into a 20 mm long foil lined tube of the type described in Example 1.
100 mg of Union Carbide PC-25, in granular form, containing 60 mg of a 1:1 propylene
glycol-glycerol mixture, was inserted into the foil lined tube. A 5mm long plug of
tobacco, about 60 mg, was located immediately behind the granular substrate in the
foil lined tube. A 48 mm long annular cellulose acetate tube with an internal 4.5
mm I.D. polypropylene tube was inserted about 3 mm into the foil lined tube. A second
foil lined tube, 50 mm in length, was inserted over the cellulose acetate tube until
it abutted against the 20 mm foil lined tube. A 5 mm long cellulose acetate filter
plug was inserted into the end of this second foil lined tube. The overall length
was 84 mm. When lit, this article produced substantial amounts of aerosol throughout
the first six puffs with a tobacco flavor.
Example 8
[0098] A smoking article was constructed as shown in Figure 5 with a 15 mm long fibrous
fuel element substantially as described in Example 7. The macrocapsule 52 was formed
from a 15 mm long piece of 4 mil (0.10 mm) thick aluminum foil, which was crimped
to form a 12 mm long capsule. This macrocapsule was loosely filled with 100 mg of
granulated PC-60, a carbon obtained from Union Carbide, and 50 mg of blended tobacco.
The granular carbon was impregnated with 60 mg of a 1:1 mixture of propylene glycol
and glycerol. The macrocapsule, the fuel element, and the mouthend piece were united
by an 85 mm long piece of conventional cigarette paper.
Example 9
[0099] A smoking article was constructed in accordance with the embodiment of Figure 6 with
a 7 mm long pressed carbon fuel element containing 90% PXC carbon and 10% SCMC. The
longitudinal passageway was 0.040 in. (1.02 mm) in diameter. This fuel plug was inserted
into a 17 mm long aluminum foil lined tube so that 3 mm of the fuel element was inside
the tube. An 8 mm diameter disc of 3.5 mil (0.089 mm) aluminum foil, with a 0.049
in. (1.24 mm) diameter center hole, was inserted into the other end of the tube and
butted against the end of the fuel source.
[0100] Union Carbide PG-60 carbon was granulated and sieved to a particle size of -6 to
+10 mesh. 80 mg of this material was used as the substrate, and 80 mg of a 1:1 mixture
of glycerin and propylene glycol was loaded on this substrate. The impregnated granules
were inserted into the foil tube and rested against the foil disk on the end of the
fuel source. 50 mg of blended tobacco was loosely placed against the substrate granules.
An additional foil disk with a 0.049 in. (1.24 mm) central hole was inserted into
the foil tube on the mouth end of the tobacco. A long hollow cellulose acetate rod
with a hollow polypropylene tube as described in Example 7 was inserted 3 mm into
the foil lined tube. A second foil lined tube was inserted over the cellulose acetate
rod against the end of the 17 mm foil lined tube.
[0101] This model delivered 11.0 mg of aerosol in the first three puffs when "smoked" under
FTC conditions. Total aerosol delivery for nine puffs was 24.9 mg.
Example 10
[0102] A smoking article having the fuel element and substrate configuration of Figure 7
was made using a 15 mm long annular pressed carbon fuel element with an inner diameter
of about 4 mm and an outer diameter of about 8 mm. The fuel was made from 90% PCB-G
activated carbon and 10% SCMC. The substrate was a 10 mm long piece formed of Union
Carbide PC-25 carbon with an external diameter of about 4 mm. The substrate, loaded
with 55 mg of a 1:1 glycerin/propylene glycol mixture, was inserted within the end
of the fuel closer to the mouth end of the article. This fuel/substrate combination
was inserted 7 mm into a 70 mm foil lined tube which had a short cellulose acetate
filter at the mouthend. The length of the article was about 77 mm.
[0103] The article delivered substantial amounts of aerosol on the first three puffs, and
over the useful life of the fuel element.
Example 11
[0104] A modified version of the smoking article of Figure 9 was made as follows: A 9.5
mm long carbon fuel source with a 4.5 mm diameter and a 1 mm diameter longitudinal
passageway was extruded from a mixture of 10% SCMC, 5% potassium carbonate, and 85%
carbonized paper mixed with 10% water. The mixture had a dough-like consistency and
was fed into an extruder. The extruded material was cut to length after drying at
80
0C overnight. The macrocapsule was made from a 22 mm long piece of 0.0089 mm thick
aluminum formed into a cylinder of 4.5 mm I.D. The macrocapsule was filled with (a)
70 mg of vermiculite containing 50 mg of a 1:1 mixture of propylene glycol and glycerin,
and (b) 30 mg of burley tobacco to which 6% glycerin and 6% propylene glycol had been
added. The fuel source and macrocapsule were joined by inserting the fuel source about
2 mm into the end of the macrocapsule. A 35 mm long polypropylene tube of 4.5 mm I.D.
was inserted in the other end of the macrocapsule. The fuel source, macrocapsule and
polypropylene tube were thus joined to form a 65 mm long, 4.5 mm diameter segment.
This segment was wrapped with several layers of Manniglas 1000 from Manning Paper
Company until a circumference of 24.7 mm was reached. The unit was then combined with
a 5 mm long cellulose acetate filter and wrapped with cigarette paper. When smoked
under FTC conditions, the article delivered 8 mg of WTPM over the initial three puffs;
7 mg WTPM over puffs 4-6; and 5 mg WTPM over puffs 7-9. Total aerosol delivery over
the 9 puffs was 20 mg. When placed horizontally on a piece of tissue paper, the article
did not ignite or even scorch the tissue paper.
1. A smoking article comprising:
(a) a carbonaceous fuel element;
(b) a physically separate aerosol generating means including a substrate bearing an
aerosol forming material ; and
(c) a mouthend piece; the fuel element and the substrate being arranged in a conductive
heat exchange relationship such that the heat stable substrate receives conductive
heat transfer substantially throughout the time of burning of the fuel element.
2. The article of claim 1, wherein the fuel element is less than about 30 mm in length.
3. An elongated smoking article comprising:
(a) a combustible fuel element less than about 30 mm in length, and having a density
of at least 0.5 g/cc.;
(b) an aerosol generating means in conductive heat exchange relationship with the
fuel element; and
(c) means for delivering the aerosol produced by the aerosol generating means to the
user.
4. An elongated smoking article comprising:
(a) a fuel element;
(b) a physically separate aerosol generating means including an aerosol forming material;
and
(c) an insulating member surrounding at least a portion of the fuel element.
5. The article of claim 4, wherein the fuel element and the aerosol generating means
are in a conductive heat exchange relationship.
6. The article of claim 4 or 5, wherein the fuel element is less than 30 mm in length.
7. The article of claim 1, 2, 3 or 4 which produces wet total particulate matter having
no mutagenic activity, as measured by the Ames test.
8. The article of claim 4, 5, 6 or 7, wherein the insulating member is resilient and
at least 0.5 mm thick.
9. The article of claim 8, wherein the insulating member comprises a fibrous material.
10. The article of claim 4 or 5, wherein the insulating member further surrounds at
least a portion of the aerosol generating means.
11. The article of claim 1, 3, 4, 5 or 8, wherein the fuel element is a carbonaceous
material, and is less than 20 mm in length.
12. The article of claim 1, 3, 4, 5 or 8, wherein the fuel element is less than 15
mm in length.
13. The article of claim 11, wherein the fuel element has a plurality of longitudinally
extending passages therethrough.
14. The article of claim 1, 2, 3, 4 or 8, further comprising a heat conducting member
which contacts both the fuel element and the aerosol generator means.
15. The article of claim 14, wherein the heat conducting member is metallic.
16. The article of claim 15, wherein the metallic member is a metallic foil which
encompasses at least a portion of both the fuel element and the aerosol generator
means.
17. The article of claim 16, wherein the metallic member encloses a substrate bearing
the aerosol forming material.
18. The article of claim 16, wherein the metallic member is a metallic rod embedded
within at least a portion of both the fuel element and the aerosol generator means.
19. The article of claim 16, wherein the fuel element is less than about 15 mm in
length.
20. The article of claim 1, 2, 3 or 4, wherein the aerosol generating means is at
least partially contained within a cavity in the fuel element.
21. The article of claim 1, 2, 3 or 4, wherein the aerosol generating means comprises
a porous, nonparticulate substrate, having a longitudinal passageway at least partially
therethrough.
22. The article of claim 1, 2, 3 or 4, wherein the article delivers at least about
0.6 mg of wet total particulate matter in the first three puffs under FTC smoking
conditions.
23. The article of claim 22, wherein the article delivers at least about 1.5 mg of
wet total particulate matter in the first 3 puffs under FTC smoking conditions.
24. The article of claim 1, 2, 3 or 4, wherein the article delivers an average of
at least about 0.8 mg per puff of wet total particulate matter under FTC smoking conditions,
for at least 6 puffs.
25. The article of claim 1, 3 or 4, wherein the aerosol generating means contains
a substrate loaded with from about 35 mg to 85 mg of aerosol former.
26..,The article of claim 1, 3 or 4, wherein at least about 15 weight percent of the
aerosol former is delivered as wet total particulate matter under FTC smoking conditions.
27. The article of claim 1, 3 or 4, further comprising a charge of tobacco located
between the mouth end of the fuel element and the mouth end of the article.
28. The article of claim 1, 3 or 4, wherein the fuel element produces substantially
no visible sidestream smoke during smolder.
29. The article of claim 3, 4, 5 or 8, wherein the fuel element comprises a carbon-containing
material.
30. The article of claim 29, wherein the length of the fuel element is less than 20
mm.
31. The article of claim 29, wherein the length of the fuel element is less than 15
mm.
32. An elongated smoking article comprising:
(a) a fuel element less than 30 mm in length;
(b) a physically separate aerosol generating means including a carrier bearing an
aerosol forming material ;
(c) means for conducting heat from the fuel element to the aerosol generating means;
and
(d) an insulating member which surrounds at least a portion of the fuel element.
33. The smoking article of claim 32, wherein the heat conducting means comprises a
heat conducting member which contacts both the fuel element and the aerosol generating
means.
34. The article of claim 33, wherein the heat conducting member encloses the carrier
for the aerosol forming material.
35. The article of claim 33, wherein the insulating member is resilient and is at
least 0.5 mm thick.
36. The article of claim 32, wherein the fuel elment comprises a carbon-containing
material.
37. The article of claim 36, wherein the fuel element is less than 15 mm in length.
38. The article of claim 32, 33, 34 or 35, wherein the fuel element is carbonaceous.
39. The article of claim 33, wherein the fuel element is less than 15 mm in length.
40. The article of claim 33, wherein the article delivers an average of at least 0.8
mg per puff of wet total particulate matter under FTC smoking conditions, for at least
six puffs.
41. The article of claim 32 or 38, which produces wet total particulate matter having
no mutagenic activity, as measured by the Ames test.