Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
109;~795
In recent years there has been increasing interest in tobacco substitutes
for use in the manufacture of smoking products. These substitutes include com-
positions based on natural polymers such as cellulose and starch, synthetic
polymers such as a vinyl methyl ether:maleic anhydride copolymer, and processed
parts of plants other than tobacco such as lettuce leaves and cereal grains.
Generally, these materials do not have colors that are characteristic of tobaccothereby creating a basis for non-acceptance by the consumer. This disadvantage
is widely recognized as evidenced by the solutions that have been proposed for
dealing with the problem of color. For example, United States Patent 3,638,660
discloses a tobacco substitute material based on cellulose with appropriate
dyes being added to enhance the appearance of the substitute. United States
Patent 3,931,824 also describes a cellulosic material as a tobacco substitute
with coloring agents such as carbon, iron oxide, food dyes, tobacco extracts,
organic colorants and inorganic pigments being incorporated into the material
in amounts up to about 5% of the total composition. Although the foregoing
coloring agents may be effective for providing the desired color, they are not
totally satisfactory because they may give rise to objectionable flavors upon
smoking tobacco substitute materials containing such agents or they may be im-
practical for large scale commercial use due to economic considerations.
The present invention affords a convenient and economical method for im-
parting a tobacco-like color to tobacco substitute materials by applying tob-
acco dust to the surface of such materials.
According to the invention there is provided a smoking material compris-
ing a cut, shredded or otherwise comminuted tobacco substitute to which has
been applied on the surface of said cut, shredded or otherwise comminuted tob-
acco substitute an adhesive derived from a carbohydrate and a coating of tob-
acco dust which comprises tobacco particles predominantly less than about 75
microns in diameter.
The tobacco dust may be adhesively applied to cut or shredded tobacco
substitute materials by means of a suitable binder or adhesive agent. The re-
sulting coated substitute material have an appearance similar to that of cut
or shredded tobacco.
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In forming the product of the invention, the tobacco substitute
materisl is first cut, shredded or otherwise comminuted to give the desired
particle sizes. For example, sheets or thin pieces of the material are cut at
about 30 cuts per inch when the material is to be used in the manufacture of
cigarettes. The moisture content of the tobacco substitute should be adjusted,
prior to cutting, to optimum levels for the particular substitute used. Ex-
cessive moisture levels should be avoided in order to prevent possible adverse
effects on the tobacco substitute and to reduce energy requirements associated
with removal of any excess moisture which may be present after the substitute
has been coated with tobacco dust.
The cut or comminuted tobacco substitute is treated with a suitable
adhesive agent under conditions that will give a relatively uniform coating of
the agent on the surface of the tobacco substitute. Convenient apparatus for
applying the adhesive agent comprises an inclined rotating drum in combination
with spray means whereby a solution of the adhesive agent is sprayed onto the
tobacco substitute material as it is agitated by the action of the tumbling
drum. Adhesives which may be used in the practice of this invention are
those which provide the necessary binding properties but which do not have an
adverse effect on the taste and aroma of the final smoking product. Preferred
adhesives include those derived from carbohydrates such as starch, cellulose
and sucrose. Specific examples include dextrins, corn syrup, carboxymethyl-
cellulose, invert sugar and lasses. The adhesives are preferably applied
in solution form using water, alcohol, glycerol or combinations thereof as the
vehicle. If desired, the adhesives may be applied to the surface of the tobac-
co substitute in dry powder form with water, alcohol or other suitable liquids
being subsequently sprayed onto the treated surface to activate the adhesive.
The use of glycerol in con~unction with the adhesives is particularly advanta-
geous in that its humectant and plasticizing properties tend to reduce brittle-
ness associated with the adhesives after they have been applied to the tobacco
sub-
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lQ5~;~75~5
stitute and tried.
The amount of adhesive agent required per unit weight of tobacco
substitute will depend on several factors including the bonding properties of
the adhesive used, the density of the tobacco substitute and the surface area
of the tobacco substitute particles. It is preferred that the adhesive agent
or agents be used in amounts that are adequate for effecting the necessary
bonding of the tobacco dust but without an appreciable excess thereof. General-
ly speaking, the minimum quantities of adhesive required are approximately 5
percent by weight (total solits content) based on the dry weight of the tobacco
substitute being treated. The concentration of adhesive agent in the solvent
vehicle selected should be such that the viscosity of the resulting solution
will permit a uniform coating of adhesive to be applied to the tobacco substi-
tute by spraying or other application means. It is desirable to employ solu-
tions with the highest practicable concentrations of adhesive agent that are
consistent with satisfactory ~esults so that moisture levels of the tobacco
substitute being treated are not increased excessively.
Following treatment with the adhesive agent and while the adhesive
coating is still sticky or tacky, the tobacco substitute is treated with suf-
ficient tobacco dust to give the degree of color desired. Tobacco dust is
defined here as finely divided tobacco comprising particles less than about 75
microns in diameter. Although such tobacco dust can be obtained by grinding
whole leaves, strips or other tobacco plant parts, it is more economical to
obtain the dust from tobacco fines which are routinely collected as a by-productin the manufacture of tobacco products. For example, the mechanical abrasion
to which tobacco is subjected in cutting, drying and conveying operations give
rise to substantial quantities of tobacco fines which must be recycled in some
way to prevent economic losses that would otherwise be incurred. Such tobacco
fines, however, normally contain a significant proportion of particles greater
than 200 microns in diameter thereby rendering them unsuitable for use in the
present invention. It is therefore necessary to subject tobacco fines obtained
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from normal manufacturing operations to a grinding or milling treatment in
order to obtain the desired particle sizes.
Grinding or milling of tobacco particles to produce tobacco dust
having the desired particle size can be effected in any suitable manner. For
example, a ceramic mill designated as a DM-3C SWEC0 Vibro-Energy Dry Grinding
Mill and which is available from SWEC0 Inc. of Los Angeles, California has
been fount to be satisfactory for milling tobacco. Better milling results are
obtainet if the tobacco materials are dried prior to milling. A moisture con-
tent of less than 5 percent and preferably less than 3 percent is desirable
for both the tobacco materials prior to grinding and the resulting tobacco dust
which is to be applied to the tobacco substitute. The application of very dry
tobacco dust to the athesive coating on the tobacco substitute gives better
adhesion of the dust ant serves to counteract the elevatet moisture levels
which result from treating the tobacco substitute with the adhesive agent solu-
tion.
It is important that the major portion of the tobacco tust applied
to the tobacco substitute consists largely of particles less than 75 microns in
tiameter, preferably less than 30 microns ant most preferably less than 10 mic-
rons in diameter. The smaller particle sizes provide a more uniform coating on
the surface of the tobacco substitute, require less dust per unit area of ex-
posed surface and protuce a more even color and texture. Also, the smaller `
particle sizes are less likely to become dislodged turing subsequent processing
of the tobacco substitute.
In applying tobacco dust to a tobacco substitute coated with adhesive,
it is necessary to agitate or stir the mass of material to insure that all sur-
faces of the tobacco substitute are coatet with tust. Any suitable apparatus
may be uset for this purpose including, for example, the inclined rotating drum
suggestet above in connection with the application of adhesive. Following ap- ~ -
plication of the tobacco dust, the treated tobacco substitute is dried in a
conventional manner to a moisture level appropriate for the additional proces-
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10S~7~5
sing associated with the manufacture of the desired smoking product. If more
color is desired treatment of the dust-bearing tobacco substitute may be re-
peated to incorporate additional adhesive and tobacco dust.
The ~ollowing examples will serve to further illustrate the present
invention.
EXAMPLE 1 7
. _
Tobacco fines obtained from the manufacture of cigarettes were dried
in an oven maintained at 125 C. until the moisture content of the fines was
approximately 2 percent. The fines were thenmilledin a DM-3C SWEC0 Vibro-
Energy Dry Grinding Mill until essentially all of the particles were less than10 microns in diameter as tetermined by particle size analysis. This analysis
was based on the general methods described by R.L. Harris in Public Health
Service Publication No. 614, Sec. B-7A. The dry tobacco dust was set aside
for subsequent use.
A commercially available tobacco substitute sold under the trademark, ~;
Cytrel, and available from Celanese Corporation of New York, N.Y. as Cytrel
Type 361 was shredded to a size compatible with the manufacture of cigarettes. ~
In a rotating drum were placed 120 grams of the shredded Cytrel having a mois- -` -
, ~ ,~ .,
ture content of about 7 percent and 30 grams of powdered corn syrup solids were
added to the Cytrel as it tumbled in the rotating drum to give corn syrup solids -~
uniformly coated on the surface of the Cytrel. The adhesive properties of the
corn syrup solids were then activated by spraying the treated Cytrel with a
mixture of 25 grams of glycerol, 11 grams of ethanol and 1 gram of water. ~ ~ -
Agitation of the sprayed material in the rotating drum was continued and 60
grams of the previously prepared tobacco tust were introduced into the rotating
drum. The tobacco dust-caoted substitute material was found to have a uniform
color closely resembling that of shredded tobacco.
EXAMPLE 2
The general procedure of Example 1 was repeated except that the
tobacco substitute treated was shredded popped corn as described in United
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States Patent No. 3,964,495. The 120 grams of shredded popped corn were
treated sequentially in the rotating drum with 30 grams of powdered corn syrup
solids, a mixture of 25 grams of glycerol, 7.5 grams of ethanol and 1 gram
water, and finally 60 grams of tobacco dust. The product had a uniform coating
of dust with a tobacco-like color.
EXAMPLE 3
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Tobacco dust was prepared as described in Example 1. A 120-gram
sample of shredded Cytrel was placed in a rotating drum and sprayed with an
adhesive mixture of glycerol (12 grams), ethanol (15 grams), water (1 gram)
and a commercial caramelized sugar product (12 grams) sold by Sethness Products
Company of Chicago, Illinois as Double Strength Caramel Color. After spraying
with the adhesive mixture, 30 grams of the previously prepared tobacco dust
were introduced into the rotating drum and rotation of the drum was continued
for a short period of time to ensure uniform distribution of the tobacco dust.
The resulting product was dried to about 12 percent moisture and was found to
be very similar in appearance to shredded tobacco.
EXAMPLE 4
Tobacco dust was prepared as described in Example 1. A 120-gram ~`
sample of shredded popped corn (see United States Patent No. 3,964,495) was
placed in a rotating drum and sprayed with adhesive mixture identical with that
described in Example 3. The sprayed material was then treated with 30 grams of
the previously prepared tobacco dust and agitation of the treated sample was
continued until the dust was uniformly distributed on the surface of the popped
corn. The product was removed from the rotating drum and dried to about 12
percent moisture. The product was uniformly colored by the tobacco dust and
was quite similar in appearance to shredded tobacco.
While the foregoing teachings describe specific steps for practicing
the present invention, it is apparent to those skilled in the art that changes
and variations may be made in the various steps without departing from the
spirit of the invention or the scope of the appended claims. Such changes and
variations are considered to be a part of this invention.
