U.S. patent number 3,638,660 [Application Number 04/758,872] was granted by the patent office on 1972-02-01 for method for making a tobacco substitute composition.
Invention is credited to Howard J. Davis.
United States Patent |
3,638,660 |
Davis |
February 1, 1972 |
METHOD FOR MAKING A TOBACCO SUBSTITUTE COMPOSITION
Abstract
A method of making a tobacco substitute material is disclosed
which involves the use of fibrous woodpulp which contains at least
90 percent of alpha cellulose. The selected wood pulp of high alpha
cellulose count is lightly beaten to a Canadian Standard Freeness
of between 400-700 ml. and is then combined with a nontoxic
combustion modifier and formed into a sheet having a density of
12-35 lbs./ft..sup.3. The combustion modifiers useable are the
potassium, sodium and magnesium sulphates, magnesium and potassium
chlorides, sodium, potassium, magnesium and ammonium carbonates and
bicarbonates, potassium nitrate, ferric oxide, ferric hydroxide,
alumina, magnesium gluconate, citrate, citrate and acetate and
gluconic acid. The metallic compounds utilized are preferably used
in their hydrated form.
Inventors: |
Davis; Howard J. (Martinsville,
NJ) |
Family
ID: |
25053424 |
Appl.
No.: |
04/758,872 |
Filed: |
September 10, 1968 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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473916 |
Jul 21, 1965 |
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32211 |
May 27, 1960 |
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9763 |
Feb 9, 1960 |
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Current U.S.
Class: |
131/369; 131/352;
131/334 |
Current CPC
Class: |
A24B
15/16 (20130101) |
Current International
Class: |
A24B
15/16 (20060101); A24B 15/00 (20060101); A24b
003/14 () |
Field of
Search: |
;162/139,157,187
;131/2,17,15,140 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Stedman, R. L. "The Chemical Composition of Tobacco and Tobacco
Smoke" U.S. Dept. of Agriculture Publication 19118 p. 190 cited
.
Shmuk (text) "The Chemistry and Technology of Tobacco" pub. by
Pishchepromizdat (Moscow) 1953 p. 497-499 & p. 594-595 .
"Smoking and Health" Report of the Advisory Committee to the
Surgeon General of the Public Health Service, Public Health Service
Publication No. 1103 (1964).
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Primary Examiner: Rein; Melvin D.
Parent Case Text
The present application is a continuation-in-part of Ser. No.
473,916, filed July 21, 1965, which is a continuation-in-part of
application Ser. No. 32,211, filed May 27, 1960, now abandoned,
which in turn is a continuation-in-part of application Ser. No.
9,763, filed Feb. 19, 1960, and now abandoned.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A method for producing a tobacco substitute comprising lightly
beating fibrous woodpulp containing at least 90 percent alpha
cellulose to a Canadian Standard Freeness of between 400 and 700
ml., intimately combining said woodpulp with from 2 to 25 percent,
based on the weight of the woodpulp, of an orally nontoxic
combustion modifier selected from the group consisting of the
sulfates of magnesium, sodium and potassium; the chlorides of
potassium and magnesium; the carbonates and bicarbonates of sodium,
potassium, magnesium and ammonia; potassium nitrate; ferric oxide;
ferric hydroxide; alumina; the gluconates, citrates and acetates of
magnesium; and gluconic acid, and forming a sheet therefrom, said
sheet having a density of 12 to 35 lbs./ft..sup.3.
2. The method of claim 1 wherein the said combustion modifier is a
hydrated metal compound.
3. The method of claim 1 wherein said woodpulp contains at least 92
percent alpha cellulose.
4. The method of claim 1 further comprising shredding said paper
sheet into narrow strips of nonuniform length and width.
5. The method of claim 1 wherein an amount of alpha cellulose is
added such that said alpha cellulose constitutes at least 60
percent of the total weight of the tobacco substitute.
Description
This invention relates broadly to smoking materials, and is more
particularly concerned with cigarettes.
It is an object of this invention to provide a novel smoking
material particularly suitable as a replacement, in whole or in
part, for tobacco in cigarettes.
Another object is the provision of a cigarette or like smoking
materials containing cellulose and additives which change the
burning characteristics of the cellulose to produce a pleasing
smoke.
An additional object of the present invention is to provide a
smoking material for the manufacture of cigarettes which permits
the control of, and more particularly the reduction of the smoke
condensate from such cigarettes, as compared with that which is
obtained from conventional all-tobacco cigarettes.
A further object of this invention is the provision of a smoking
material which when smoked as a cigarette in a conventional smoking
cycle produces a smoke condensate with a substantially lower
polycyclic aromatic hydrocarbon content than that which is obtained
from conventional tobacco cigarettes, and more particularly a smoke
condensate whose content of 3,4-benzpyrene (a carcinogen) is lower
than that which is commonly obtained from conventional all-tobacco
cigarettes.
An additional object of the present invention is to provide an
economical, quickly produced and readily available smoking material
which can also be blended with tobacco to produce a more economical
cigarette whose smoke contains a reduced amount of condensable
material and a reduced amount of 3,4-benzpyrene, as compared with a
conventional all-tobacco cigarette.
A still further object of the invention lies in the provision of a
method of producing a smoking material at low density, featuring
beating woodpulp to a Canadian Standard Freeness of between about
400 to 700 ml., whereby the resultant sheet has a relatively low
density, resulting when blended with a hydrated metal compound and
formed into a smoking material, a remarkably low tar content.
Other objects of this invention will be apparent from the following
detailed description, particularly when taken in connection with
the accompanying drawings.
In the drawings:
FIG. 1 is a view of my cigarette;
FIG. 2 is a schematic portrayal of an exemplary process for
applying the additives to the paper, followed by a drying step;
and
FIGS. 3, 4 and 5 are charts showing the results of vapor phase
determinations on conventional nonfilter cigarettes and cigarettes
produced in accordance with the present invention.
Cellulose, when used as a tobacco substitute in a cigarette, burns
rapidly with a characteristic yellow flame and an odor like that of
burning rags. When a hydrated metal compound exemplified by
magnesium sulfate, magnesium acetate, magnesium citrate and the
like is incorporated, e.g., in amount of 10 percent, into the
cellulose the burning rate approaches that found in ordinary cured
tobacco leaves, the odor of the side stream and the taste of the
main stream are much more pleasant, the color of the flame front or
coal is different and the ash is dense and self-supporting (and
much lighter in color than the ash of the unmodified cellulose
cigarette).
In accordance with one aspect of this invention, I have found that
the amount of tar produced in the smoking of cigarettes containing
the mixture of cellulose and magnesium sulfate and related
compounds may be reduced by using as the cellulose a lightly beaten
woodpulp of high alpha cellulose content. Beating of pulp is a
conventional operation in the making of paper. It involves
mechanically working the fibers in the presence of water, usually
on a machine called a beater, such as the Hollander, Horne,
Niagara, Jones, Betram, Victory, Vortex and rod mill beaters
described in Pulp and Paper manufacture, Vol. 2, Preparation of
Stock for Paper Making, edited by J. N. stephenson, first edition,
published in 1951 by McGraw-Hill Book Company, Inc. pages 200-212.
I have obtained very good results by beating the pulp to such an
extent that it will form a paper which withstands mechanical
processing, particularly processing in the wet state (e.g., passage
through an aqueous dipping bath without disintegrating), and
stopping the beating before the pulp has lost most of its
"freeness." Generally speaking, the beating should be stopped when
the freeness of the pulp is in the range of 400-700 ml., preferably
about 500-600 ml. (as measured in accordance with TAPPI Standard
T227 m- 50, which uses a Canadian Standard Freeness tester of the
general type shown at pages 238 and 239 of Stephenson Pulp and
Paper Manufacture Vol 2 (previously cited). The beaten pulp is then
formed into paper, as by depositing the pulp on any suitable
paper-forming screen e.g., a Fourdrinier screen or Valley Mold),
pressing and drying. Suitably, the rate of deposition and amount of
pressing are such that the resulting dried paper has an average
thickness in the range of about 3 to 10 mils. Sheet thickness is
inversely proportional to sheet bulk density, for fixed areal
density. Tests have shown that relatively low squeeze pressures
produce a lower density sheet and a lower total condensate when
formed into a cigarette and smoked.
Best results are obtained when there are also present substances
which modify the burning characteristics of cigarettes comprising
cellulose and hydrated magnesium sulfate. It is especially
desirable to add inorganic compounds, e.g., salts, which help
sustain the burning of the cigarette, particularly during the
resting period of the usual smoking cycle, when oxygen is not being
forcibly drawn into the burning zone. Examples of such burning
sustainers are potassium chloride, magnesium chloride, potassium
sulfate, potassium nitrate, and ferric oxide and hydroxide.
Certain burning sustainers have a particularly desirable additional
effect, in that they increase the rate of burning; examples of such
materials are the carbonates and bicarbonates, e.g., potassium,
sodium, magnesium and ammonium carbonate or bicarbonate. It is
believed that the potassium, sodium and ammonium carbonates react
with part of the magnesium sulfate to form magnesium carbonate
during the application of these compounds. The presence of the
carbonate during burning is believed to cause an expansion of the
burning zone and is believed to permit more air to penetrate to all
parts of the burning particles, thus promoting more complete
combustion. The presence of the carbonate also causes an expansion
of the ash so that the ash is more porous. In addition, the use of
carbonates materially decreases the acid content of the smoke.
Potassium carbonate is particularly suitable since it not only is a
carbonate, but also supplies potassium which is very effective to
maintain the burn. Other burning sustainers which increase the rate
of burning, when used in suitable concentrations, are sodium
sulfate, potassium nitrate and similar salts.
The flavoring of the cigarette may be improved by the incorporation
of flavoring agents. These may be of the type used commercially for
the flavoring of tobacco such as menthol, tonka bean, powdered deer
tongue, licorice or the proprietary mixtures known as "Alva: G-1,
G-6, G-16, G-189, G-32 and G-327" supplied by Van
Ameringen-Haebler, Inc., Division of International Flavors and
Fragrances, Inc. Vanillin has an excellent effect on the flavor and
odor of the cigarette, making these considerably milder. The usual
household vanilla extract may be incorporated in the cellulose for
this purpose.
It is also desirable to have a humectant present in order to
prevent the tobacco substitute from drying out unduly. Any of the
usual humectants used in cigarette manufacture may be employed; for
example, sorbitol, which is preferred, or other humectant
polyhydric alcohol, e.g., glycerol, may be used. The moisture
content of the tobacco substitute may be within the range of about
5 to 25 percent, preferably about 10 to 15 percent, exclusive of
the moisture present as water of hydration.
I may also incorporate nicotine or other alkaloid in the synthetic
smoking material. The presence of the alkaloid gives an increased
feeling of satisfaction to the users of the synthetic smoking
material. The nicotine may be supplied, for example, as such or in
the form of its sulfate, or citrate or citrate-sulfate, malonate or
malate. Preferably, the amount of nicotine used is insufficient, in
itself, to impart any pronounced color to the synthetic smoking
material; its effect in this respect, even if impure colored
nicotine is used, is merely a slight tinting of the product.
I may also incorporate an ammonium compound. Thus, compounds such
as ammonium sulfate, ammonium carbonate, ammonium persulfate and
ammonium perchlorate act to release ammonia and thus raise the pH
of the side stream. The presence of the ammonia thus formed is also
believed to have an effect in inhibiting the production of
undesirable 3,4-benzpyrene during smoldering. The use of ammonium
compounds also results in the formation of whiter ash.
To enhance the appearance of the tobacco substitute, a coloring
agent may be incorporated. Although the color is preferably a
tobaccolike brown or yellow-brown, colors such as purple and pink
may be used. Among the colors are those certified by the Food and
Drug Administration such as F.D. and C. (Food, Drug & Cosmetic
Act) Yellow No. 5; F.D. and C. Chocolate Brown, New Shade B; C.I.
17590; Brown PG; 20170 Brown Y; 30045 Yellow-Brown K.
This invention makes it possible to produce a cigarette which
yields a smoke containing a very small amount of condensate (tar),
and in which the burning temperature during smoking is in the
critical range of about 750.degree. to 900.degree. C. for only a
very small fraction of the total smoking time. It is known that
burning temperatures in the aforesaid critical range promote the
formation of certain polycyclic aromatic compounds, such as
3,4-benzpyrene, which are carcinogenic. In conventional cigarettes
the burning temperature is in the critical range for much longer
times. This is readily demonstrated by standard burning temperature
profiles. Burning temperature profiles of cigarettes are obtained,
in a standard manner, by continuously recording the temperature at
a fixed point of the cigarette while the cigarette is being smokes
in a standard manner, as described by G. P. Touey and R. C
Mumpower, Tobacco 144, 18 (1957). More particularly, a platinum/87
percent Pt. 13 percent Rh fine wire thermocouple is placed at a
point 25 mm. back from that end of the cigarette which is to be
lit. The junction of the thermocouple is at the longitudinal axis
of the cigarette while the two fine wires leading to the junction
are at right angles to that axis and pass, through the cigarette
paper, on opposite sides of the junction, the paper being suitably
sealed about the wires to prevent entrance of air and movement of
the thermocouple. The cigarette is smoked by means of a machine
which draws air through the lit cigarette and then expels the
indrawn gas and smoke into the atmosphere. More particularly, in
the work described in the atmosphere. More particularly, in the
work described in this application, the machine has a piston
operating in a cylinder connected to the cigarette through a trap
cooled by a dry ice-acetone mixture. The volume displaced by
movement of the piston in the cylinder is 35 ml., and the cylinder
is maintained at room temperature (25.degree. C.). The smoking
machine is operated on a 30 second cycle, in which air is drawn
through the lit cigarette and into the cylinder, by movement of the
piston, for 2 seconds; the gas in the cylinder is then expelled to
the room, by movement of the piston for 2 seconds; and the
apparatus then remains stationary for 26 seconds, so that the
cigarette is in the resting stage for 28 seconds. With this
arrangement a standard tobacco cigarette, 70 mm. long and 22-26 mm.
in circumference and having no filter tip, will smoke down to a 25
mm. butt in about 12 to 14 cycles. Alternatively, I may use a 60
second cycle, having a resting stage of 58 seconds, with similar
two second intake strokes and two second exhaust strokes.
The instrument used for measuring temperature must have a high
speed of response. For this purpose I have used a Sargent
Multi-range Recorder (Cat. No. S72151, E. H. Sargent & Co.)
having a temperature response characteristic of 11/4 seconds for
the full scale of recording, the setup being such that the full
scale of recording covers 1,150.degree. C.
In a conventional tobacco cigarette, during each puff of the
smoking cycle (that is, during the 2-second intake of the gas) the
temperature at the thermocouple junction rises as the cigarette
burns back towards the junction. The temperature at the
thermocouple drops slightly after each puff, at the beginning of
each rest period, but when the temperature during the puff rises
into the critical temperature range the resting temperature stays
within the critical range. There is a long period of time when the
temperature in a substantial portion of the cigarette, extending
back from the lit end, is in the critical range. The temperature
profiles of cigarettes of typical tobacco substitutes made in
accordance with this invention are in sharp contrast to those of
typical tobacco cigarettes. The temperature drops off sharply after
each puff and even after the puff temperature has come into the
critical temperature range, the resting temperature is well outside
that range. In addition, only a very small part of the cigarette is
at a temperature in the critical range during the smoking cycle.
For example, in the cycle just before the cigarette burns back to
the thermocouple, the thermocouple temperature is in the critical
range for less than 50 percent, preferably less than 10 percent,
and more preferably less than 5 percent, of the time. The initial
slope of the curve descending from each peak temperature within the
critical range is much steeper than that of the tobacco cigarette,
being considerably steeper than - 3,000.degree. C./min., usually
sharper than about - 6,000.degree. C./min. and preferably sharper
than about - 9,000.degree. C./min.
The slope of the curve ascending to each peak temperature within
the critical range is also much higher than that of the tobacco
cigarette, being well above 3,000.degree. C./min., usually sharper
than about 5,000.degree. C./min. and preferably sharper than
6,000.degree. C./min. The difference between the peak temperature
and the next succeeding minimum of the resting temperature during
the two time cycles starting one puff before the highest
temperature puff is usually at least about 200.degree. C.,
preferably at least about 250.degree. C.
Acceptable results are attained by the use of hydrated magnesium
sulfate as the hydrated metal compound to favorably modify the
burning rate of the cellulose tobacco substitute; this compound
markedly improves the flavor and odor of burning cellulose. Other
hydrated metal compounds are sodium sulfate, hydrated alumina,
magnesium citrate, magnesium acetate and calcium tartrate. Mixtures
of compounds may be used; thus magnesia and sodium sulfate may be
applied so as to form magnesium sulfate in situ. Similarly,
magnesium chloride and potassium sulfate may be applied for the
same purpose. Also, gluconic acid or magnesium gluconate are
effective substitutes. It will be understood that, like hydrated
magnesium sulfate, the other hydrates may be used with burning
sustainers, flavoring agents, humectants, nicotine, ammonium
compounds, or other modifying agents, individually or in any
combination.
The proportion of the burning rate controller of hydrated metal
compounds mentioned is desirably in the range of about 10 to 15
percent, based on the total air-dry weight of the tobacco
substitute. The proportion of the salt which is a burning sustainer
is desirably in the range of about 1/2 to 5 percent, preferably
about 1 to 4 percent, based on the total air-dry weight of tobacco
substitute. Advantageously, the proportion of burning sustainer is
such as to insure that the cigarette remains lit during the resting
portion of the cycle, but should not be so high that the cigarette
will flare or flame during the puffing portion of the cycle, and
preferably not so high as to seriously impair the taste or odor. In
general, the precise amount of burning sustainer for best results
will depend on the physical form of the cellulose and the amount of
hydrated MgSO.sub.4 (or other compound which lowers the burning
rate). When potassium carbonate or bicarbonate is used as a burning
sustainer the proportion for best results generally falls in the
range of about 1/2 to 2 percent, preferably about 1 to 1.8 percent,
based on the total air-dry weight of the tobacco substitute. For
other carbonates, proportions providing the same content of
CO.sub.3 are desirable.
The amount of flavoring agent is desirably in the range of about
0.001 to 10 percent with the best results usually obtained with the
proportions within the range of about 1/10 to 1/12 percent, based
on the total air-dry weight of the product. The proportion of
humectants is desirably in the range of about 0.001 to 10 percent,
preferably about 11/2 to 21/2 percent, based on the total air-dry
weight of the tobacco substitute. The proportion of nicotine, when
used, is desirably in the range of up to about 2 percent,
preferably about 1/2 to 11/2 percent, based on the weight of the
cellulose. The amount of the ammonium compound, when used, is
desirably in the range of about 1/2 to 2 percent, preferably about
1/2 to 11/4, calculated as NH.sub.3, and based on the total air-dry
weight of the tobacco substitute. A suitable proportion of coloring
agent, when used is desirably in the range of about 0.1 to 3
percent, preferably when 1/5 to 1 percent, based on the weight of
the cellulose.
The cellulose used should have an alpha cellulose content of at
least 90 percent, preferably at least 92 percent, e.g., 95 percent,
such as acetate grade or viscose grade wood pulp. It is desirable
that the alpha cellulose constitute a major portion, preferably at
least about 60 percent, of the total air-dry weight of the tobacco
substitute. Some suitable sources of wood pulp are hemlock, spruce
and other coniferous firs.
The cellulose should be combined intimately with the additive or
additives to be employed. This may be done conveniently by
saturating a sheet of paper made from the lightly beaten cellulose
with a solution, dispersion or emulsion of the additives, which may
be applied separately or all together, followed by drying and
shredding the sheet or cutting it into strips. If desired, a sheet
may be cut into strips or shreds and sprayed with a solution or
dispersion of the additive or additives and then aged or tumbled to
assist in the uniform distribution of the additive material on the
cellulose, and thereafter dried. All or any part of the additive
material may be incorporated into the cellulose in the course of a
papermaking operation. One convenient way of doing this is by
incorporating the water-soluble additive material into a beaten
pulp stock, then forming the stock into paper on a conventional
papermaking machine, thereafter treating the paper, preferably
while still wet, with a solution or emulsion of nonwater soluble
materials and of the more expensive water-soluble constituents
(e.g., nicotine), followed by drying and shredding. In this case
the white water, drained from the papermaking machine, contains the
water soluble additives and may be reused. More economically the
other constituents are applied to the paper after it has left the
Fourdrinier screen of the papermaking machine, as by spraying an
aqueous solution thereof onto the wet sheet on the papermaking
screen or, more advantageously, by passing the formed paper
continuously through said solution.
When incorporating the additives into performed paper it is
convenient to pass the paper through an aqueous bath in an
apparatus such as shown in FIG. 2, in which the paper 11 is passed
under an idler roll 12 in the bath 13 and then moves out of the
bath, but still carrying a film of the bath liquid, through a pair
of precisely spaced squeeze rolls 14 and 15, which press out any
excess liquid. The wet paper, supported on a belt 16, is then dried
by hot air in a drier 17. The paper 11 may, if desired, have had
added thereto 1 to 2 percent of a conventional wet strength
addition.
As previously discussed, potassium carbonate and other carbonates
tend to react with part of the magnesium sulfate to form magnesium
carbonate. When both the carbonate and the magnesium sulfate are
present in the same aqueous bath the resulting insoluble magnesium
carbonate must be kept in suspension if it is desired that it be
incorporated in the paper uniformly with the water soluble
constituents. It is sometimes more advantageous to apply the
soluble carbonate separately. This may be done by applying an
aqueous solution of the carbonate to the paper before or after the
solution of the sulfate is applied. The amount of carbonate is
small relative to the amount of magnesium sulfate and a small
amount of the carbonate solution may be applied, as by a coating
roller, just before the paper is saturated with the magnesium
sulfate solution, without any intermediate drying step.
The amount of solution or dispersion, and of the constituents of
such solution and dispersion, taken by the paper will depend on
such factors as the moisture content and porosity of the paper, the
length of time the paper is immersed in the solution and the extent
to which the paper is pressed or squeezed after it leaves the
saturating bath. Accordingly, it is best to determine the
concentrations of the solutions by preliminary trials for each type
of machine and process. Suitable concentrations of magnesium
sulfate in water are, for example, in the range of about 2 to 40
percent, with the other constituents in proportion, in accordance
with the ratio of such constituents to magnesium sulfate desired in
the product. When the potassium carbonate is applied separately its
concentration in water may be, for example, in the range of about
1/2 to 6 percent. When the carbonate is applied after the sulfate
(or other water-soluble hydrate) the tendency for the latter to be
extracted from the cellulose by the carbonate solution may be
reduced by using a mixture of water and a water-miscible organic
solvent, such as ethanol, to dissolve the carbonate; in this case
the carbonate tends to deposit preferentially on the cellulose, in
a proportion greater than when a water solution of the same
concentration of the same carbonate is applied. Loss of sulfate by
extraction into the carbonate solution may also be reduced by
spraying the carbonate solution onto the sulfate-cellulose blend,
rather than dipping the blend in the aqueous carbonate
solution.
A particularly good cigarette is obtained when the tobacco
substitute is in the form of thin, narrow strips of nonuniform,
e.g., random, length and width the cigarette is easier to light,
the filler has better packing quality and the cigarette has a
better appearance. Strips may be for example from 0.2 to 2 mm. in
width and from 1 to 25 mm. in length. The paper need not be uniform
in thickness. I have found it desirable to use paper of variable
thickness and low density; in fact portions of the paper may be
less than 3 mils in thickness. Such nonconformity may be attained
by depositing the pulp slurry onto the paper-forming screen
nonuniformly, as by tilting the screen slightly transversely across
the width of the sheet, or by only lightly stirring the mass of
slurry so that it is relatively heterogeneous (of varying
concentration in different parts of the slurry) during the
operation of depositing the slurry onto the screen through a slit
of nonuniform width.
The cut or shredded tobacco substitute may be processed exactly
like tobacco on the usual cigarette-making machines, such as those
shown in U.S. Pat. Nos. 1,787,551; 2,190,032; 2,208,504; 2,247,413;
2,236,579; or 2,671,452.
The cut or shredded tobacco substitute may also be blended with
tobacco itself, with tobacco extract or with any of the usual
reconstituted tobaccos. The proportion of cured tobacco thus
blended with tobacco substitute may be in the range of about 5 to
75 percent, for example. When the proportion of tobacco is
considerable, e.g., over 50 percent, it may be desirable to
decrease the proportion of, or omit entirely, the nicotine, and
flavoring agent in the tobacco substitute.
As previously stated, the use of low density paper base from the
lightly beaten pulp makes possible a considerable reduction in the
amount of smoke condensate (tar) produced in the smoking of the
cellulose-based cigarette. Thus, in one experiment comparing
cigarettes made from equal weights of pulps having freeness values
of about 560 ml. and about 250 ml., respectively, the smoke of the
former contained about one-third the tar of the latter. I do not
have any clear explanation for this unpredictable effect. It may be
that the greater porosity leads to more complete combustion or to
better filtration of the smoke passing through the cigarette. Other
complex physical and physico-chemical interations probably occur.
This invention makes not only for a reduction in the amount of
smoke condensate but also provides a condensate very low in
polycyclic aromatics (as indicated by its very low
fluorescence).
If desired, the entire tobacco substitute may be diluted by mixing
the same with a noncombustible filler. Examples of suitable fillers
are clay (e.g., bentonite or attapulgus clay) and alumina, e.g., in
proportion of about 30 percent.
The following examples are given to illustrate this invention
further.
EXAMPLE I
A 4 percent aqueous slurry of viscose grade sulphite wood pulp
containing about 92 percent alpha cellulose was beaten in a
hollander beater until a freeness value, determined according to
TAPPI Standard T 227 m-50, of 574 ml. was obtained. Beating was
then discontinued. The beaten pulp stock was diluted to 1 percent
consistency. A measured volume of the 1 percent slurry was
suspended in a measured volume of concentrated aqueous solution of
MgSO.sub.4. 7H.sub.2 O, (NH.sub.4).sub.2 SO.sub.4 and sorbitol. The
additives-treated pulp suspension was formed into a paper sheet in
conventional manner, at low squeeze pressures to produce a
low-density sheet, and dried. The dried sheet was dipped into a
60/40 (by volume) solution of ethanol/water at 25.degree. C.
containing 5.0 grams potassium carbonate and 4.0 grams nicotine per
liter. The residence time of the sheet in the dipping solution was
about 2 seconds. The impregnated paper, which did not disintegrate
during dipping, was dried and then cut and shredded into filler
strips whose lengths varied randomly from 1 millimeter to 25
millimeters and whose widths varied randomly from 0.3 millimeter to
1.3 millimeter. The filler was conditioned overnight at 65 percent
R.H. and 75.degree. F. and made into cigarettes, using standard
cigarette paper for the wrapper. The average weight of these
cigarettes was 0.96 grams of which 50 milligrams was the weight of
the cigarette paper wrapper and the cigarette length was 70
millimeters.
In this example the proportions used were so chosen that the air
dried tobacco substitute showed the following analysis:
MgSO.sub.4.sup.. 7H.sub.2 O 13.3 % Mg(NO.sub.3).sub.2 6H.sub.2 O
1.8 % Sorbitol 1.2 % (NH.sub.4).sub.2 SO.sub.4 3.3 % K.sub.2
CO.sub.3 1.2 % Nicotine 1 %
EXAMPLE II
Example I was repeated except that the aqueous solution containing
magnesium sulfate, magnesium nitrate, sorbitol and ammonium sulfate
was used to impregnate paper made from the beaten pulp stock,
instead of adding the solution to the stock.
EXAMPLE III
Cigarettes were prepared in generally the manner of example I,
except that the saturating solutions contained solely nicotine,
sorbitol and two levels (5 and 25 percent) of either magnesium
sulfate, magnesium acetate or magnesium citrate. The ratio of salts
to sorbitol to nicotine was 50:4.3:3.9 in all samples.
The following temperature profiles were obtained:
Peak .degree. C. Rest .degree. C.
__________________________________________________________________________
MgSO.sub.4.sup.. 7H.sub.2 O at 5 % level 850-1,025 675-700 at 25 %
level 765-1,065 550-685
Mg(OAc).sub.2.sup.. 4H.sub.2 O at 5 % level 850-1,150 640-640 at 25
% level 910-1,150 640-725
Mg.sub.3 (Citrate).sub.2.sup.. ?H.sub.2 O at 5 % level 925-1,150
550-685 at 25 % level 870-1,150 --
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The cigarettes as above were smoked, and other cigarettes were
prepared in which the treated and shredded cellulosic base was
mixed with 5 and 95 percent tobacco. The magnesium acetate samples
burned very well with no difficulty in sustaining burning. The ash
appearance was good, although somewhat fluffy and white. The taste
was much better than the magnesium sulfate samples, however, the
smoke was somewhat difficult to inhale. The citrate samples burned
well at both levels and at both tobacco levels. The smoke was
milder and could be inhaled. No sulfide odors were noticed, and the
aftertaste was less. The ash at the lower level closely resembled
that of a commercial cigarette.
EXAMPLE IV
Cigarettes were again prepared in the manner of example I, except
that in one series of tests about 15 percent of gluconic acid was
substituted for the magnesium salts, and in another series about 15
percent magnesium gluconate was used. In the first case the peak
temperature was in the range of 960.degree. to 1,150.degree. C.,
the rest temperature ranged from 640.degree. to 810.degree. C.,
while with magnesium gluconate these temperatures were 845.degree.
to 990.degree. and 595.degree. to 675.degree. , respectively.
In both cases the shredded and treated cellulosic base was blended
with 50 percent tobacco from a conventional cigarette and smoked.
The smoke was extremely mild, pleasant and could be inhaled.
The following examples will illustrate the invention further.
A high alpha cellulose content (acetate grade) woodpulp slurry,
made from 1.5 pounds of woodpulp and 48 pounds of water, was
charged into a beater purchased from Valley Iron Works. The slurry
was beaten to a freeness of approximately 645 ml. (as measured in
accordance with TAPPI Standard T 227M-50), using a Canadian
Standard Freeness tester.
Approximately 100 cc. of the pulp slurry was removed from the
beater, diluted with water to 1,000 cc. to give a pulp
concentration of about 0.3 percent by weight, and was then added to
a Valley Sheet mold which had previously been substantially filled
with water. The excess water was drained off, the sheet produced
was removed from the screen, placed between sheets of blotter
paper, rolled lightly and carefully dried upon a steam plate drier
with a canvas cover on the sheet. The low density sheet obtained
was then saturated with the following formulation, providing when
air dry a sheet containing approximately a 15 percent magnesium
sulfate heptahydrate:
Wt. % in product
__________________________________________________________________________
Cellulose 66.5 Magnesium sulfate 8.0 Potassium nitrate 1.17
Ammonium sulfate 3.23 Potassium bicarbonate 1.40 Sorbitol 1.24
Nicotine 0.95 Food colors 0.40 Flavors 0.10 Water 17
__________________________________________________________________________
When dry, the saturated sheet was made into cigarettes in the
manner described in the subject patent application, and the
cigarettes were machine smoked. Ten cigarettes were smoked and the
volatiles are estimated to comprise about 50 percent water and the
remainder organic tars. After the trap was allowed to reach room
temperature it was weighed, and the weight difference represents
total condensate.
It was found that when the pulp was beaten to a freeness of
approximately 645 ml. as described above and using low squeeze
pressure to get a low-density paper, the total condensate obtained
was 12.3 mg. per cigarette with each cigarette in these tests
weighing approximately 0.8 grams.
The procedure outlined above was again followed, except that the
pulp slurry was beaten for a total time of approximately 40 minutes
to a freeness of value of 290 ml. The total condensate obtained was
49.2 mg. per cigarette as measured in the manner earlier
described.
The beating was allowed to continue for a total time of
approximately 100 minutes in a third trial, providing a freeness
value of 62 ml. Following the same procedure as in the first trial,
the total condensate was about 80.5 mg. per cigarette.
The foregoing trials clearly demonstrate that by employing a
low-density base paper from a lightly beaten pulp, that is, one
having a high-freeness value, the total condensate and consequently
the tars therein are held to a very low value. On the other hand,
beating to a low freeness value markedly increases the amount of
total tars in the smokeable material produced.
Both high- and low-density paper can be made from a high freeness
pulp, using low squeeze pressure to get a low-density paper. The
effect on tar values of employing a low density sheet (12-35
lbs./ft..sup.3), preferably 15-25 lbs./ft..sup.3, made from pulp
with a high freeness value, was confirmed by a series of trials
which demonstrated the relationship sheet density to tar
values.
In this series of trials a pulp slurry of the same formulation as
above described as beaten for approximately 10 minutes to a
freeness value of about 600 ml. After being processed through the
same sheet mold, dried and saturated with the formulation above set
forth, the sheets obtained, which measured 8 inches square and
contained 3 grams of cellulose, were placed in a hydraulic press
and subjected in a group of three experiments to differing ram or
squeeze pressures.
In a first test relatively light pressure of 5 p.s.i.g. was
employed to obtain a sheet having a thickness of about 8 mils. The
sheet was then made into cigarettes, machine smoked as previously
described, and the total condensate measured. It was found that a
sheet subjected to the pressure noted and having the thickness
mentioned provided a total condensate of 25.+-. 5 mg. per cigarette
when measured as above. The sheet had a density of 20 pounds per
cubic foot, or 0.32 grams per cubic centimeter.
A second test was performed in which the sheet was subjected in the
hydraulic press to a ram pressure of about 65 p.s.i.g. to produce a
sheet thickness of 5.1 mils. Cigarettes made from such a sheet when
machine smoked as previously gave a total condensate value of
50.+-. 5 mg. per cigarette. The sheet had a density of 32 pounds
per cubic foot or 0.51 grams per cubic centimeter.
In a third test a sheet in the hydraulic press was subject to a
pressure of about 300 p.s.i.g., to provide a sheet having a
thickness of 4.5 mils. The total condensate obtained from
cigarettes produced and smoked was 70.+-. mg. per cigarette. The
sheet density was 35 pounds per cubic foot or 0.56 grams per cubic
centimeter.
In another set of trials using pulp specified to contain alpha
cellulose in excess of 94 percent, hand sheets were made by
procedures outlined above, and using the aforesaid sheet mold, the
pulp was beaten as previously described to a Canadian Freeness
value of 585 ml. .+-. ml..+-. 35 ml. and dried under varying light
pressures to yield the following range of sheet densities and
thicknesses:
Thickness Trial in inches Density lb./ft..sup.3 Tar mg./cigarettes
__________________________________________________________________________
A 0.0080 20 26.7 B 0.0051 32 47.2 C 0.0045 35 67.0
__________________________________________________________________________
the sheets were saturated as disclosed above, shredded, and made
into cigarettes weighing about 1 gram each. The values of smoke
condensate found are given in the above table in the column labeled
"Tar".
The same pulp was shipped to a commercial paper maker and beaten in
commercial equipment to the aforementioned freeness specification,
converted on a commercial Fourdrinier paper making machine and
dried under minimum drying pressures, (about 5 p.s.i.g.). The
sheets so produced had a thickness of 0.008 inches and a density of
21 lbs./ft..sup.3. After saturating as before, cigarettes were made
from this commercial sheet and the condensate yield was found to be
about 25 mg./cigarette.
The above described trials clearly demonstrate the importance of
employing a low density sheet obtained by beating the pulp to a
high freeness value in order to provide a low-tar smoking
material.
A series of tests have also been conducted which demonstrate that
when the cigarettes of this invention are smoked there is present
in the smoke less total condensate and total phenols, as compared
with conventional nonfilter cigarettes, and further, which display
in vapor phase analyses relatively lesser amount of the major
molecules components reported to be harmful substances in the smoke
of conventional nonfilter cigarettes.
A first group of cigarettes (designated in table A below as group
I) was prepared for the above determinations essentially as
described in examples I and II of the (instant) patent application,
using substantially the formulation appearing therein.
A second group of cigarettes (designated as group II in table A)
was prepared in a like manner, except that the total amount of
additives was varied from about 8 to 16 to 24 to 32 to 40 percent
by weight of air dried product. A third group of cigarettes
(designated as group III in table B below) was prepared employing
simply magnesium sulfate and high-alpha cellulose, and in a
successive series of formulations, by adding to the sulfate and
cellulose base, certain additional salts. A fourth group of
cigarettes (referred to as group IV in table B) was provided by
conventional all-tobacco nonfilter cigarettes. ##SPC1##
##SPC2##
1. The phenol determinations were conducted using generally the
techniques described by D. Hoffman & E. L. Wynder, Beitrage zur
Tabakforschung, No. 3, pp. 101-106 (1961), and a smoking machine
substantially as disclosed by A. O'Keefe and R. Lieser, Tobacco
Science, 2, 73 (1958) was employed therein. A 2-second puff of 35
cc. volume every 30 seconds was employed. The mainstream cigarette
smoke was condensed on a glass fiber filter pad at room
temperature, located between the smoking machine and cigarette
holder. All cigarettes were 85 mm. in length and were smoked to a
25 millimeter butt, and also were conditioned and smoked at 60
percent relative humidity at 72.degree. F.
The cigarettes were screened by weight prior to smoking, and
cigarettes weighing within .+-. 0.08 grams of the average cigarette
weight were selected. Each determination of phenol in the smoke
consisted of smoking six cigarettes on a single smoking machine
position, and collecting the total condensable material in a single
trap. The total condensate weight was obtained from the difference
in pad weight before and after smoking. Aqueous sodium hydroxide
solution (5percent NaOH) was then added to the pad to remove the
condensate.
A Perkin-Elmer Model 225 Gas Chromatograph was used in the analysis
of the phenolic fraction of the smoke condensate. This unit is
equipped with a flame ionization detector. Chromatograph separation
of the phenolic fraction of the condensate was achieved with a 100
foot Golay (capillary) column having a 0.02 inch internal diameter
coated with a 85/15 mixture of Cellulube 550/Empol Dimer Acid.
The tabulation appearing as table "A" clearly demonstrates by a
comparison of the results obtained from the cigarettes of groups I
and II that the instantly disclosed smoking materials have a
markedly lower total phenol and cresol content, as well as a lower
total condensate, on a per puff basis, when measured under
experimentally equivalent conditions with a conventional
all-tobacco nonfilter cigarette of Group IV.
As well, when reference is made to the results set forth for the
cigarettes noted as group III in table "A", the instant applicant's
novel combination of magnesium sulfate and cellulose, by
themselves, is much lower in phenolics, cresols and total wet
condensate on a "per puff" basis, again compared with a
conventional all-tobacco nonfilter cigarette. This same tabulation
also demonstrates without question that when certain listed slat
constituents are added to the sulfate and cellulose base, quite
unexpectedly the phenolic compounds and cresols are much below
those for a conventional all-tobacco nonfilter cigarette, and the
total wet condensates are also considerably less when compared on
an equivalent puff basis.
Additionally, it is manifest from a review of the results noted for
the cigarettes identified as group II that even through the
magnesium sulfate content disclosed in the present application is
controllably varied over the range set forth in the application,
and proportionate modifications are made in the other salt
additives, the value for total phenols and cresols, as well as the
total wet condensate, consistently remains at values drastically
below those for a conventional all-tobacco nonfilter cigarette.
In the tables to which reference was made, the value for total
phenol and cresols is measured in micrograms per cigarette, while
condensate is measured in milligrams per cigarette. The total wet
condensate is collected and weighed at room temperature and
includes water of combustion.
A second series of determinations, namely vapor phase analyses from
puffs comparable to the fifth puff from a conventional cigarette,
were conducted by locating a precision gas sampling valve in the
live between the glass fiber filter pad and the chromatograph.
The results of these extensive studies are summarized on the
attached charts designated as FIGS. 3, 4 and 5. These are precise
reproductions of typical chromatographs obtained from the vapor
phase of smoke, FIG. 3 showing the results obtained from the
cigarettes of group I (F-38) and group IV, and FIG. 3 portraying
the vapor phase results from the cigarettes of group II. The vapor
phase analysis from the cigarettes of group III will be discussed
later. In the attached charts, the major molecular components are
listed thereon, and the relative amounts present in the
substantially comparable puffs are proportional to the peak areas
displayed.
It is observed from FIG. 3 that the light hydrocarbons such as
methane, ethane and the like are much lower than a commercial
all-tobacco nonfilter cigarette, which is indicative of a more
complete combustion epoch. Notably, isoprene is barely detectable
This highly reactive compound in both chemical and physiological
systems, is a known precursor of known toxins, as well as
carcinogenic polynuclear substances. Similarly, a much lesser
amount of acetaldehyde was found to be present. As is known,
acetaldehyde has been reported to have a synergistic effect with
acrolein, which is a harmful component of cigarette smoke in
inhibiting normal ciliary activity. A publication on this point is
Inhibitory Effects of Tobacco Smoke on the Ciliary Activity of the
Respiratory Epithelium and the Nature of the Compounds Responsible
R. Guillerm, R. Badre and B. Vignon.
Additionally, by reference to FIG. 3, it can be seen that even the
instantly disclosed cellulose base by itself, while of course not
completely suitable in unmodified form as a smoking material,
displays generally lesser amounts of the listed molecular
components. Even more important, however, is the fact that when the
total amount of disclosed additives was widely varied, major
improvements are seen when compared with a commercial all-tobacco
nonfilter cigarette.
Vapor phase determinations have also been made on the cigarettes of
group III, and these appear as FIG. 4. It has been found with the
exception of the cigarettes made from cellulose and 15 %
MgSO.sub.4.sup.. 7H.sub.2 O plus 3.2 % (NH.sub.4).sub.2 SO.sub.4,
which exhibited a slightly lower reduction in the charted molecular
components, the cigarettes in this group showed over a 75 percent
reduction in light hydrocarbons, greater than a 90 percent
reduction in isoprene, more than an 80 percent lowering of
acetaldehyde, a reduction exceeding 70 percent in methanol and
acrolein, a lessening of methyl ethyl ketone by over 90 percent,
and a reduction of more than 90 percent in toluene.
The total condensate from 40 cigarettes is subjected to a solvent
partitioning scheme to enrich the polynuclear aromatic hydrocarbons
(PAH). Further fractionation is achieved on a silica gel adsorption
column eluted with methanol. Final fractionation is achieved on
acetylated paper chromatograms. The 3,4-benzpyrene spot is excised
and extracted with methanol and quantitatively measured with a
spectrophotofluorometer of appropriate sensitivity.
The 3,4-benzpyrene content from machine made cigarettes produced in
accordance with example I was found to be 0.6 micrograms per 100
cigarettes. Quite by contrast, the 3,4-benzpyrene content from
conventional all-tobacco nonfilter cigarettes was found to be 4 to
6 micrograms per 100 cigarettes.
It is to be pointed out that the cellulose base employed in each of
the above-described trials was beaten to within a Canadian Standard
Freeness range of 400 to 700 ml., and specifically, to about 550
ml.
In the description and claims all proportions are by weight unless
otherwise indicated. In the above specification, the proportions
are expressed in terms of the compounds originally supplied,
disregarding any chemical reaction between the compounds. Thus,
although potassium carbonate interacts with part of the magnesium
carbonate, the analyses, (based on the amounts of K.,SO.sub.4,Mg
and CO.sub.3 present in the product) are expressed as percentages
of potassium carbonate and magnesium sulfate.
In the above examples, the cigarette paper used was a standard
nonporous cigarette paper (e.g., "Yorkshire" paper sold by Sears
Roebuck & Co.). If desired microperforated paper, well known to
the cigarette art, may be used instead.
It is to be understood that the foregoing detailed description is
given merely by way of illustration and that many variations may be
made therein without departing from the spirit of my invention.
* * * * *