Matrix entrapment of flavorings for smoking articles

A novel composition for flavoring smoking articles contains a soluble flavoring material, an appropriate solvent for the flavoring material, triacetin and a moisture-releasing hydrophilic polymer. Smoking articles containing the composition and methods for making such smoking articles are disclosed.

The present invention relates generally to smoking articles, and more 
particularly to a means for stably entrapping a flavor in smoking articles 
for release upon smoking. 
BACKGROUND OF THE INVENTION 
Flavorants are commonly added to cigarettes and other smoking articles, 
during the manufacturing process to achieve desired taste and smell 
sensations during smoking. Many tobacco flavoring materials, including the 
commonly employed menthol flavorant, however, are volatile and tend to 
vaporize and gradually escape from the cigarette between the time the 
cigarette is made and the time it is smoked. 
One method employed to compensate for this loss of flavorant over storage 
time involved applying a greater amount of the flavoring material to the 
cigarette during its manufacture. However, when the cigarette is stored 
for an extended period or subjected to varying conditions of temperature 
and humidity prior to smoking, a significant loss of flavor occurs 
resulting in failure to achieve the desired taste and smell sensations 
upon smoking. 
Other flavor release methods which have been employed in smoking materials 
fall into four categories, including the use of compounds or complexes 
which decompose to release the flavorant, the use of capsules rupturable 
upon the manual application of pressure thereof which contain the 
flavorant, flavorants, releasable upon thermal activation and encapsulated 
flavors released by moisture application. 
In one exemplary cigarette construction described in U.S. Pat. No. 
3,006,347, a flavor is encapsulated in a film forming vehicle having as 
its basic chemical constituent a polysaccharide, a polypeptide, or 
mixtures thereof. The encapsulated flavor is applied to the cigarette 
paper. The flavor is released by heating the vehicle to a temperature 
sufficiently high to degrade the film-forming vehicle structure. Thus, the 
useful application of the flavor and vehicle is limited to only those 
regions of the cigarette that will experience sufficiently high 
temperatures during smoking, such as the tobacco filler itself or the 
cigarette paper surrounding the filler. Moreover, the temperatures 
required to destroy the vehicle structure and release the flavor are 
sufficiently high to permit flavor release only in the vicinity of the 
coal. Thus, the flavor must be applied along the whole length of the 
tobacco rod wrapper to ensure a consistent level of release and delivery 
of flavor during smoking. Such a vehicle is difficult to apply to the 
cigarette paper during cigarette manufacture. 
There remains, therefore, a need in the art for methods and materials 
enabling the retention of volatile flavoring materials in smoking articles 
under a variety of storage conditions and durations. 
SUMMARY OF THE INVENTION 
The present invention alleviates to a great extent the shortcomings of 
known tobacco flavoring methods by providing in one aspect a composition 
capable of stably entrapping and progressively releasing flavor in smoking 
articles. More specifically, the invention provides for a flavoring 
entrapped within a film forming composition that progressively releases 
the flavoring upon reaction with water vapor present in the smoke. The 
composition involves an admixture of a selected soluble flavoring material 
in an appropriate solvent, an effective amount of triacetin, and a 
moisture releasing hydrophilic polymer. The composition may also contain 
an effective amount of water to adjust the admixture to a desired 
viscosity for application to a smoking article. 
The composition may be adapted to contain a variety of conventional 
flavorings employed in the manufacture of cigarettes, cigars and the like, 
including menthol, citrus, chocolate, licorice, mint and breath freshener 
flavors. Similarly, in accordance with the broadly described composition 
of the present invention, the solvent may be selected from a number of 
solvents conventionally employed in the tobacco industry, such as 
alcohols, e.g., ethanol and peppermint oil. It is also possible, depending 
on the solubility of the flavoring material selected, for the solvent to 
be triacetin. The polymer is desirably selected from among esters of 
polyvinyl alcohols, polysaccharides, pectins, gelatins, starches, or 
mixtures thereof, but may also be any hydrophilic polymer capable of 
degrading upon contact with moisture laden smoke. Triacetin may also vary 
in proportion but is essential to the composition. In the absence of 
triacetin, little, if any, flavoring may be retained in the composition. 
The parameters of one desirable embodiment of the composition according to 
the invention includes between about 1 to 25 parts by weight menthol; 
between about 1 to 25 parts by weight ethanol; between about 1 to 10 parts 
by weight triacetin; and between about 20 to 80 parts by weight 
polyvinylacetate [PVA]. A preferred composition more specifically contains 
about 2.0 parts by weight menthol, about 1 part by weight ethanol, about 
0.5 part by weight triacetin, and about 7 parts by weight 
polyvinylacetate. To adjust the viscosity of the preferred embodiment 
about 1-15 parts by weight water may be added thereto. The ethanol content 
of the composition may be increased if desired, but decreasing the ethanol 
content may result in undissolved excess methanol. 
The ratio of PVA to menthol is preferably about 3.5 parts PVA to 1.0 part 
menthol. A sufficient amount of the PVA matrix must be present to form a 
film and retain the menthol. However, increasing the relative amount of 
PVA proportionately decreases the accessability or release rate of the 
menthol, because increased moisture exposure is required to initiate 
menthol release. 
As another aspect of the present invention, a smoking article is provided 
comprising a source of moisture containing smoke; and a moisture-soluble, 
film-forming composition comprising a flavoring material as previously 
described. By utilizing such a moisture release flavor composition, the 
flavor may be applied at any position on the smoking article where it will 
be exposed to the moisture carrying smoke. Thus, flavor may be applied to 
or dispersed in essentially any part of a conventional cigarette, such as 
in the tobacco filler, in the filter plug on the inside surface of the 
cigarette paper wrapper surrounding the tobacco filler, or coated on the 
inside surface of the filter plug wrapper or the tipping paper. Where the 
filter is fibrous, the composition may be dispersed through at least a 
portion of it. Alternatively where the filter has at least one cavity, the 
composition may be located within the cavity. Additionally, the 
flavor-containing composition may be applied to other smoking articles 
such as cigars and cigarillos and the like, and to smoking devices, such 
as cigarette holders, cigar holders and pipes. 
As yet a further aspect of the invention, there is provided a method for 
making a flavor-releasing smoking article involving a specific sequence of 
steps. These steps include initially admixing the soluble flavoring 
material with the selected solvent and then adding triacetin to that 
mixture. This resulting mixture is added at a slow rate to the 
moisture-releasing hydrophilic polymer and the final composition is 
applied to a smoking article where it will be exposed to 
moisture-containing smoke. The method also includes providing a source of 
moisture-containing smoke, e.g., a tobacco rod, capable of causing the 
composition to progressively release the flavoring material. 
The applying step of the method may include coating the composition onto 
the inner surface of the cigarette or filter wrapping paper; dispersing 
the composition as a foam in the tobacco filler or filter material and 
locating the composition in a cavity within the filter or tobacco. 
The solvents, flavoring materials and polymers described above for use in 
the composition may similarly be employed in the method. A preferred 
embodiment of the method provides for admixing about two parts by weight 
menthol, with at least about one part by weight ethanol; adding about 0.5 
part by weight triacetin; and admixing from four to twenty parts by weight 
polyvinylacetate therewith. 
The composition, smoking articles employing the composition, and methods 
for making the smoking articles of the present invention provide a novel 
flavoring system for smoking articles which maintains its ability to 
release flavor for long periods of time under a variety of temperature and 
humidity conditions. Further, the methods and materials of the invention 
provide a flavoring system which also yields the selected flavor 
progressively during smoking. 
Other aspects and advantages of the present invention will be readily 
apparent upon consideration of the following detailed description of the 
preferred embodiments thereof. 
DETAILED DESCRIPTION 
As previously described, the flavoring composition of the present invention 
may be applied to parts of the cigarette other than the plug wrap which 
are exposed to the moisture carrying cigarette smoke. For example, a 
composition according to the present invention may be applied within the 
filter itself, dispersed or concentrated in discrete regions therein or in 
other parts of the cigarette. Moreover, a compound filter element may be 
employed in which one portion contains the composition. 
The following examples illustrate practice of the invention in the 
production of compositions and smoking articles for retention of flavor 
under variant conditions and for progressive delivery of the flavor during 
smoking:

EXAMPLE 1 
In one preferred embodiment of the present invention, the flavor 
composition can be applied as a coating on the inside of the plug wrap of 
a filter cigarette. 
In a typical filter cigarette, a tobacco column is overwrapped by a 
cigarette wrapper which is adhered to itself at an adhesive seam. Filter 
plug material is overwrapped by a plug wrapper, which is also adhered to 
itself at a seam. Another optional adhesive seam serves to adhere the plug 
wrapper to the filter plug. Tripping paper adheringly overwaraps and joins 
the plug wrap and cigarette wrapper. 
The plug wrap may be coated with the composition solution prior to its 
incorporation into the cigarette. If the coated plug wrap is applied to 
the filter plug material before the coating dries, the coating may soak 
into the surface of the filter plug to some extent. Thus, the coating may 
also aid the adherence of the plug wrap to the filter plug. Any effect on 
the the porosity through the plug wrap to the filter plug may be accounted 
for in vented filter constructions. 
EXAMPLE 2 
The storability and delivery of a smoking article according to the present 
invention was observed by coating a cigarette plug wrap on one side with 
the following composition: Five milligrams of menthol was solubilized with 
fifteen grams of ethanol (95 percent solution) and then mixed with fifteen 
grams of triacetin. This mixture was then warmed slightly above room 
temperature. Five grams of this solution was admixed with ten grams of 
PVA. The resulting mixture was applied to the cigarette plug wrap and 
allowed to dry. The plug wrap was wrapped around cellulose acetate filter 
plugs with the coated side toward the filter. The wrapped filters were 
stored in boxes for about two months, and then formed into cigarettes. 
While the cigarettes were being smoked the menthol content on a puff by 
puff basis was recorded as shown in Table I below. 
TABLE I 
______________________________________ 
puff 1 2 3 4 5 6 7 8 
______________________________________ 
menthol .02 .03 .03 .03 .04 .05 .07 .12 
(mg/puff) 
______________________________________ 
A further feature of the flavor delivery composition according to the 
invention is illustrated in this example. As shown in the results 
tabulated above, a significant increase in flavor delivery levels occurs 
from the sixth to the ninth puff of a cigarette prepared as described 
above. Consequently, the composition may be applied to the cigarette in 
reduced quantities such that the level of flavor delivery during the early 
puffs is below the taste threshold and that only during the sixth to ninth 
puff, when the flavor delivery increases, is the flavor level sufficient 
to exceed the taste threshold. For example, the taste threshold for 
menthol is about 0.025 milligram per puff. By timing delivery in this way, 
a flavor, such as a breath freshener, may be delivered only at the end of 
the cigarette. This effect may also be utilized in smoking articles other 
than cigarettes. 
A similar effect is achieved by increasing the proportion of PVA in the 
solution. The accessibility of the flavor is decreased and during initial 
puffs, the flavor delivery is below the taste threshold. During the last 
puff or puffs however, sufficient moisture has been provided to the 
flavoring system to release menthol above the threshold taste level. 
EXAMPLE 3 
To determine the effectiveness of the composition in retaining the 
flavoring under a variety of storage conditions, the following study was 
conducted. A composition according to the present invention was prepared 
by mixing together on a weight basis ratio, about 2.0 parts menthol, about 
1.0 part ethanol, and about 0.5 part triacetin. PVA was admixed in the 
solution at a ratio of about 3.5 parts PVA to about one part menthol. 
Water was also added at a ratio of about 1.5 parts H.sub.2 O to 2.0 parts 
menthol to adjust the viscosity of the composition. 
Plug wrap was coated on one side with the mixture and used to wrap 
cellulose acetate filter plugs (21 mm in length and 25 mm in 
circumference) with the coated side toward the filter. Average total 
weight of about 35.5 milligrams of coating (to yield an average 
application of 5.9 milligrams of menthol) was evenly applied to each plug 
wrap. Cigarettes were made by joining the filters to 63 mm tobacco rods 
and were divided into two groups. 
One group of cigarettes was placed in a room at lab conditions of 
75.degree. F. and 60% relative humidity, the other group was placed in a 
room at desert conditions of 110.degree. F. and 15% relative humidity. A 
number of coated cigarettes having the same structure and blend and having 
about 5.9 milligrams of menthol evenly added to the filler were placed in 
each of the rooms at the same time. All cigarettes were sealed in packs. 
Initially, and at periodic intervals, cigarettes were removed from the 
rooms and analyzed for menthol content in the smoke. The results of these 
studies are shown in Table II. 
TABLE II 
__________________________________________________________________________ 
Mg Menthol 
Mg Menthol/Puff 
Sample In All Puff Number 
Days Stored 
Type Puffs 1 2 3 4 5 6 7 8 9 
__________________________________________________________________________ 
Lab Room Conditions 
0 Control 
0.57 .sup.(a) 
.06 
.06 
.07 
.08 
.08 
.08 
.08 
.08 
Experimental 
0.68 .04 
.04 
.04 
.04 
.04 
.05 
.06 
.09 
.15 
20 Control 
0.63 .02 
.04 
.06 
.06 
.07 
.08 
.09 
.08 
.09 
Experimental 
0.68 .02 
.04 
.04 
.04 
.05 
.06 
.07 
.10 
.18 
29 Control 
0.58 .04 
.05 
.06 
.07 
.08 
.08 
.09 
.09 
.08 
Experimental 
0.70 .03 
.04 
.04 
.05 
.05 
.05 
.08 
.13 
.21 
57 Control 
0.58 .03 
.05 
.05 
.06 
.06 
.06 
.07 
.07 
.sup.(a) 
Experimental 
0.73 .04 
.04 
.04 
.04 
.05 
.05 
.07 
.10 
.14 
85 Control 
.046 .sup.(b) 
Experimental 
.058 .sup.(b) 
168 Control 
0.42 .sup.(b) 
Experimental 
0.64 .sup.(b) 
Desert Conditions 
8 Control 
0.47 .sup.(a) 
.04 
.04 
.05 
.06 
.06 
.06 
.07 
.11 
Experimental 
0.62 .04 
.04 
.05 
.05 
.05 
.06 
.06 
.09 
.15 
27 Control 
0.38 .03 
.04 
.05 
.05 
.06 
.06 
.08 
.12 
.sup.(a) 
Experimental 
0.65 .05 
.07 
.06 
.07 
.08 
.09 
.13 
.19 
.sup.(a) 
37 Control 
0.46 .sup.(b) 
Experimental 
0.5 .sup.(b) 
76 Control 
0.32 .sup.(b) 
Experimental 
0.69 .sup.(b) 
114 Control 
0.26 .03 
.04 
.05 
.06 
.07 
.07 
.09 
.sup.(a) 
.sup.(a) 
Experimental 
0.54 .04 
.08 
.07 
.08 
.10 
.12 
.17 
.sup.(a) 
.sup.(a) 
168 Control 
0.28 .sup.(b) 
Experimental 
0.57 .sup.(b) 
__________________________________________________________________________ 
.sup.(a) No data point collected. 
.sup.(b) Puff by puff data not available. 
The tabulated results unexpectedly illustrate good flavor retention and 
delivery during smoking in both desirable laboratory conditions and harsh 
desert conditions. 
EXAMPLE 4 
Yet another composition according to the present invention was developed 
and tested for flavor delivery. A composition was prepared by mixing 
together on a weight basis ratio about 2.0 parts menthol, about 1.0 part 
ethanol, and about 1.0 part triacetin. To this is added about 16.0 parts 
PVA and about 1.5 parts water. Cigarettes were made as in Example 3 with 
an average total weight of about 8-10 milligrams per cavity evenly coated 
on each plug wrap. The cigarettes were smoked and the menthol content on a 
puff by puff basis was as shown in Table III. 
TABLE III 
______________________________________ 
puff 1 2 3 4 5 6 7 
______________________________________ 
menthol .01 .02 .02 .02 .04 .04 .06 
(mg/puff) 
______________________________________ 
The results demonstrate a consistent delivery of flavor over time, with the 
heaviest delivery occurring in the later draws upon the cigarette. 
EXAMPLE 5 
A flavoring composition according to the present invention may also be 
coated on part of the cigarette other then the plugwrap, such as the 
filter fibers. Even when only the plugwrap is coated as the PVA film 
dries, some of the menthol in the composition may migrate into the 
cellulose acetate filter fibers or into the filler. 
Cigarettes were produced on Day 1 using a flavoring composition applied to 
filler, filter and plugwrap in two different concentrations. A flavoring 
composition of 7 parts PVA, 2 parts menthol, 1 part ethyl alcohol, 0.5 
parts triacetin and 1.5 parts water was applied to two sets of cigarettes 
at coating weights of (A) 5.0 grams of solution/25 rods or 74.7 grams of 
solution/m.sup.2 plug wrap and (B) 2.5 grams solution/25 rods or 37.35 
grams of solution/m.sup.2 plug wrap. 
Table IV below illustrates the "storability" of such a flavorant over time 
and in various parts of the cigarette. 
TABLE 4 
______________________________________ 
Mg Menthol/Puff 
Storage Mg Puff No. 
Time Sample Type 
Menthol 1 2 3 4 5 6 7 
______________________________________ 
1 month 
A - Smoke .63 .05 .07 .07 .08 .08 .11 .18 
1 month 
B - Smoke .42 .02 .04 .04 .05 .06 .07 .11 
11 A - Smoke .66 .06 .08 .08 .08 .09 .12 .14 
months 
1 month 
A - Filter 4.98 
1 month 
B - Filter 2.96 
11 A - Filter 3.19 
months 
1 month 
A - Plugwrap 
2.09 
1 month 
B - Plugwrap 
2.96 
11 A - Plugwrap 
1.25 
months 
______________________________________ 
A = 5.0 g solution/25 rods 
B = 2.5 g solution/25 rods 
The unexpected efficacy of the composition of the present invention in 
retaining flavor over time is clear. In contrast, a conventional 
commercially-available menthol cigarette experiences a decided decrease in 
flavor retention over storage time. 
In one study, such a conventional cigarette stored in desert conditions of 
110.degree. F. and 15% relative humidity, decreased in menthol flavor 
delivery from 0.57 milligram of menthol in smoke when fresh to 0.24 
milligram after six months. A cigarette treated according to the present 
invention with 74.7 grams of solution per square meter of plugwrap 
experienced a small decrease over the same time and under the same 
conditions of 0.63 to 0.57 milligram of menthol in smoke. 
EXAMPLE 6 
When all the flavorant composition is applied to the center of the filter, 
delivery of menthol flavor in smoke was found to be equivalent to filters 
having treated plugwraps only. In this study, the solution described in 
Example 5 above was applied to the center of the filter at a coating wet 
weight of 2.5 grams of solution per 25 rods or 37.35 grams/m.sup.2 plug. 
The analytical data appears in Table V below. 
TABLE V 
______________________________________ 
Mg Menthol/Puff 
Puff No. 
Sample Type 
Mg. Menthol 1 2 3 4 5 6 7 
______________________________________ 
Smoke 0.42 .03 .05 .05 .05 .06 .09 .12 
Filter 3.47 
Plugwrap 0.14 
______________________________________ 
EXAMPLE 7 
As an alternative method of applying flavorant to the center of filter, the 
PVA-menthol solution of Examples 4 and 5 was applied to the center of a 
filter made of a low density cellulose acetate. This center was surrounded 
by a higher-density cellulose acetate with no trace of solution on it. The 
analytical data after seven days is shown below in Table VI. 
TABLE VI 
______________________________________ 
Mg Menthol/Puff 
Puff No. 
Sample Type 
Mg. Menthol 1 2 3 4 5 6 7 8 
______________________________________ 
Smoke 0.45 .03 .04 .05 .06 .07 .07 .08 .07 
Filter 2.8 
______________________________________ 
Numerous modifications and variations in practice of the invention are 
expected to occur to those skilled in the art upon consideration of the 
foregoing descriptions of preferred embodiments thereof. Among such 
modifications are the use of flavorants other than menthol, e.g., citrus, 
chocolate and other commonly employed cigarette flavorings and breath 
fresheners, and the substitution of other solvents or moisture-reactive 
polymers or substances such as polysaccharides, starches, pectins and 
mixtures thereof. It is apparent that various changes and modifications 
may be made in the invention without departing from the scope of the 
invention as defined by the claims appended thereto.