U.S. patent application number 13/865381 was filed with the patent office on 2013-09-05 for menthol-sorbed activated charcoal, cigarette filter, and filter-tipped cigarette.
This patent application is currently assigned to Japan Tobacco Inc.. The applicant listed for this patent is JAPAN TOBACCO INC.. Invention is credited to Yoshinori SAKAI.
Application Number | 20130228188 13/865381 |
Document ID | / |
Family ID | 45974977 |
Filed Date | 2013-09-05 |
United States Patent
Application |
20130228188 |
Kind Code |
A1 |
SAKAI; Yoshinori |
September 5, 2013 |
MENTHOL-SORBED ACTIVATED CHARCOAL, CIGARETTE FILTER, AND
FILTER-TIPPED CIGARETTE
Abstract
Menthol-sorbed activated charcoal stably holding menthol during
storage, and smoothly releasing menthol only during passage of
tobacco smoke therethrough is provided. The menthol-sorbed
activated charcoal is featured in that to activated charcoal having
a specific surface area of 1500 m.sup.2/g or more but 1700
m.sup.2/g or less as measured by the BET method, menthol is sorbed
at a sorption rate of 80% or more but 92% or less with reference to
the saturated amount of menthol for the activated charcoal.
Inventors: |
SAKAI; Yoshinori; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JAPAN TOBACCO INC. |
Tokyo |
|
JP |
|
|
Assignee: |
Japan Tobacco Inc.
Tokyo
JP
|
Family ID: |
45974977 |
Appl. No.: |
13/865381 |
Filed: |
April 18, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2011/063835 |
Jun 16, 2011 |
|
|
|
13865381 |
|
|
|
|
Current U.S.
Class: |
131/275 |
Current CPC
Class: |
A24C 5/47 20130101; A24D
3/163 20130101; A24D 3/0287 20130101; A24D 3/061 20130101; A24D
3/14 20130101 |
Class at
Publication: |
131/275 |
International
Class: |
A24D 3/14 20060101
A24D003/14 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 20, 2010 |
JP |
2010-235577 |
Claims
1. Menthol-sorbed activated charcoal comprising activated charcoal
having a specific surface area of 1500 m.sup.2/g or more but 1700
m.sup.2/g or less as measured by the BET method, with menthol being
sorbed to the activated charcoal at a sorption rate of 80% or more
but 92% or less with reference to the saturated amount of menthol
for the activated charcoal.
2. A cigarette filter containing a menthol-sorbed activated
charcoal according to claim 1.
3. The cigarette filter according to claim 2, wherein the filter
has two or more segments, and the menthol-sorbed activated charcoal
is contained in a portion thereof.
4. The cigarette filter according to claim 2, wherein the filter
material is a cellulose acetate material.
5. A cigarette comprising a cigarette filter according to claim 2.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of PCT
Application No. PCT/JP2011/063835, filed Jun. 16, 2011 and based
upon and claiming the benefit of priority from prior Japanese
Patent Application No. 2010-235577, filed Oct. 20, 2010, the entire
contents of all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to menthol-sorbed activated
charcoal, a cigarette filter, and a filter-tipped cigarette.
[0004] 2. Description of the Related Art
[0005] In cigarettes, flavorants such as menthol are used to
improve the intrinsic aroma and taste of the cigarettes. As menthol
flavoring method, the addition to cut tobacco, the addition to
inner packing paper of a package, and the addition to a filter are
known. Encapsulation of menthol is also a common practice.
[0006] It is known that, in the addition of menthol to cut tobacco
or inner packing paper, if the amount of menthol is increased, more
brown stains occur on the cigarette paper of the tobacco rod during
storage of the cigarette. The stains are attributable to the
release of dyestuffs from cut tobacco upon the volatilization of
menthol.
[0007] On the other hand, the use of menthol capsules allows the
control of the occurrence of stains on cigarette paper and the
deterioration of menthol in smoke. However, the use of menthol
capsules requires the processes of the production of the capsules
and incorporation of the capsules into the cigarette. As a result,
the production cost of cigarette will increase.
[0008] On the other hand, U.S. Pat. No. 3,236,244 describes a
filter element containing activated charcoal. Menthol is adsorbed
to the activated charcoal, to add to a tobacco flavor.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention is intended to provide menthol-sorbed
activated charcoal with stably holds the menthol during storage and
smoothly releases the menthol only during passage of tobacco smoke
therethrough, as well as a cigarette filter containing the
menthol-sorbed activated charcoal.
[0010] The present invention is also intended to provide a
cigarette which comprises the filter, stably holds the menthol
during storage over time in the menthol-sorbed activated charcoal
of the filter, smoothly releases menthol only when tobacco smoke
passes through the filter during smoking, and reduces the
occurrence of stains on the cigarette paper.
[0011] A first aspect of the present invention provides
menthol-sorbed activated charcoal comprising activated charcoal
having a specific surface area of 1500 m.sup.2/g or more but 1700
m.sup.2/g or less as measured by the BET method, with menthol being
sorbed to the activated charcoal at a sorption rate of 80% or more
but 92% or less with reference to the saturated amount of menthol
for the activated charcoal.
[0012] The activated charcoal has a relatively large specific
surface area, and has a relatively high degree of activity.
Therefore, the activated charcoal is hereinafter referred to as
"highly activated charcoal", thereby differentiating it from
general activated charcoal.
[0013] A second aspect of the present invention provides a
cigarette filter containing the menthol-sorbed activated charcoal
of the first aspect.
[0014] A third aspect of the present invention provides a
filter-tipped cigarette comprising the cigarette filter of the
second aspect.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0015] FIG. 1 shows a filter-tipped cigarette according to one
embodiment of the present invention.
[0016] FIG. 2 shows a relationship between the specific surface
area of the activated charcoal in the menthol-sorbed activated
charcoal of a filter-tipped cigarette and the amount of menthol in
tobacco smoke in the initial stage (without storage).
[0017] FIG. 3 shows the amount of menthol (relative value) in
tobacco smoke during smoking after storage of a filter-tipped
cigarette for 0.5, 1.5, and 2.5 months.
[0018] FIG. 4 shows a relationship between the specific surface
area of the activated charcoal in the menthol-sorbed activated
charcoal of a filter-tipped cigarette and the rate of occurrence of
stains on the cigarette paper.
[0019] FIG. 5 shows a relationship between the menthol sorption
rate for the menthol-sorbed activated charcoal in a filter-tipped
cigarette and the amount of menthol in tobacco smoke during
smoking.
[0020] FIG. 6 shows a relationship between the menthol sorption
rate for the menthol-sorbed activated charcoal in a filter-tipped
cigarette and the amount of menthol (relative value) in tobacco
smoke during smoking after storage under high temperature
conditions (maximum temperature 55.degree. C., humidity 35% RH) for
0.5, 1.5, 2.5, and 3.5 months.
[0021] FIG. 7 shows the amount of menthol in tobacco smoke during
smoking of the filter-tipped cigarettes of Example 1 and
Comparative Example 1 after storage under high temperature
conditions (maximum temperature 55.degree. C., humidity 35% RH) for
1, 5, and 9 weeks.
[0022] FIG. 8 shows the rate of occurrence of stains on the
cigarette paper of the filter-tipped cigarettes of Example 1 and
Comparative Example 1.
[0023] FIG. 9 shows the change in the menthol content in each puff
of the cigarettes of Example 2 and Comparative Example 2.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Embodiments of the present invention are described below in
detail.
[0025] A menthol-sorbed activated charcoal according to an
embodiment of the present invention comprises highly activated
charcoal having a specific surface area of 1500 m.sup.2/g or more
but 1700 m.sup.2/g or less as measured by the BET method, and to
the charcoal, menthol is sorbed at a sorption rate of 80% or more
but 92% or less with respect to the saturated amount of menthol for
the highly activated charcoal.
[0026] The specific surface area by the BET method may be measured
as follows:
[0027] Apparatus: Autosorb-1-MP (manufactured by Quantachrome)
[0028] Pretreatment: 0.010 g of activated charcoal sample for
measurement was heated for 15 hours in a vacuum at 0.1 Pa and 573
K,
[0029] Measurement method: the specific surface area of the
pretreated sample was calculated by the Multipoint BET method at
relative pressure P/P0=0.1 to 0.3 using the nitrogen adsorption
isotherm data obtained at a temperature of 77 K.
[0030] The highly activated charcoal may be any activated charcoal
as long as it has a specific surface area of 1500 m.sup.2/g or more
but 1700 m.sup.2/g or less as measured by the BET method. As the
highly activated charcoal, for example, coconut shell activated
charcoal may be used.
[0031] An activated charcoal having a specific surface area of less
than 1500 m.sup.2/g decreases in the amount of menthol held in the
activated charcoal in the filter-tipped cigarette. As a result, it
becomes difficult to sufficiently increase the amount of menthol in
tobacco smoke during smoking. On the other hand, an activated
charcoal having a specific surface area of more than 1700 m.sup.2/g
may rapidly decrease in the percentage of reduction of menthol
during storage.
[0032] The highly activated charcoal preferably has an average
particle size of 200 to 600 .mu.m.
[0033] When used in a filter-tipped cigarette, the sorption rate of
menthol for the highly activated charcoal is important for the
relationship between the lapsed days of storage and the amount of
menthol in tobacco smoke during smoking. If the sorption rate of
menthol is less than 80% with reference to the saturated amount of
menthol for the highly activated charcoal, the amount of menthol
held by the highly activated charcoal decreases when the charcoal
is applied to a filter-tipped cigarette. As a result, it becomes
difficult to sufficiently increase the amount of menthol in tobacco
smoke during smoking. On the other hand, if the sorption rate of
menthol is more than 92% with reference to the saturated amount of
menthol for the highly activated charcoal, the amount of menthol in
tobacco smoke during smoking may decrease with the lapsed days of
storage.
[0034] The menthol-sorbed activated charcoal according to one
embodiment can be produced by, for example, charging desired
amounts of menthol and highly activated charcoal, which has a
specific surface area of 1500 m.sup.2/g or more but 1700 m.sup.2/g
or less as measured by the BET method, into the chamber of a rotary
stirring apparatus, and allowing the menthol to be sorbed to the
highly activated charcoal while rotating the highly activated
charcoal. The chamber may be heated to an internal temperature of
40 to 80.degree. C.
[0035] Next, a cigarette filter according to an embodiment will be
described.
[0036] The cigarette filter according to an embodiment contains the
menthol-sorbed activated charcoal described above.
[0037] In one embodiment, the cigarette filter has two or more
segments and contains the menthol-sorbed activated charcoal in a
part thereof. In another embodiment, the cigarette filter has a
structure that many particles of the menthol-sorbed activated
charcoal are filled between two columnar filter materials and a
plug wrapper wraps the filter materials, including the filled
portion.
[0038] The filter material is a filter material used in ordinary
cigarette filters. For example, tow of cellulose acetate fibers may
be used. The bundle of cellulose acetate fibers can be consolidated
by the treatment with triacetin.
[0039] Next, a filter-tipped cigarette according to an embodiment
of the present invention will be described.
[0040] The filter-tipped cigarette according to an embodiment
includes the above-described cigarette filter.
[0041] In one embodiment, the filter-tipped cigarette has the
structure shown in FIG. 1. The filter-tipped cigarette includes a
tobacco rod 1, and a filter 2 having a perimeter equal to or less
than that of the tobacco rod 1. The tobacco rod 1 and the filter 2
are butted with each other at their ends, and the whole
circumference surface of the filter 2 and the circumference surface
of the tobacco rod 1 near the butted portion are wrapped by a
tipping paper 3, thereby integrating the tobacco rod 1 with the
filter 2. The tobacco rod 1 is formed by wrapping cut tobacco with
cigarette paper to form a column. The filter 2 is a segmented
filter in which a first filter material 4 and a second filter
material 5, which is serially butted to the rear end of the filter
material 4, are wrapped with a plug wrapper 6 to form a column. The
first filter material 4 is made by, for example, raveling cellulose
acetate fiber bundle, uniformly dispersing many particles of the
menthol-sorbed activated charcoal into the raveled cellulose
acetate fibers, and then binding the fibers together to form a
column. The second filter material 5 is made by, for example,
raveling cellulose acetate fiber bundle, and then binding the
fibers together to form a column. The first filter material 4, in
which the menthol-sorbed activated charcoal is dispersed is located
at the tobacco rod 1 side.
[0042] The filter will not be limited to the structure shown in
FIG. 1. The filter may have a structure made of two filter
materials opposed to each other with their ends apart from each
other at a desired distance, many particles of menthol-sorbed
activated charcoal filled between the two filter materials, and a
plug wrapper wrapping the two filter materials and the filling of
menthol-sorbed activated charcoal to form a column. The two filter
materials are made by, for example, raveling acetate fiber bundles,
and then binding the fibers together to form a column.
[0043] The above-described menthol-sorbed activated charcoal
according to one embodiment has a constitution that to the highly
activated charcoal having a specific surface area of 1500 m.sup.2/g
or more but 1700 m.sup.2/g or less as measured by the BET method,
menthol is sorbed at a sorption rate of 80% or more but 92% or less
with reference to the saturated amount of menthol for the highly
activated charcoal. Therefore, menthol is stably held during
storage, and menthol is smoothly released only during the passage
of tobacco smoke through the charcoal.
[0044] By causing the menthol-sorbed activated charcoal to be
contained in a filter, and applying this filter into a
filter-tipped cigarette, menthol is stably held over time in the
menthol-sorbed activated charcoal in the filter during storage,
menthol is smoothly released only when tobacco smoke passes through
the filter during smoking, and the occurrence of stains on the
cigarette paper is reduced. These were confirmed by the following
tests.
[0045] <Test I>
[0046] Coconut shell activated charcoals having specific surface
areas of 700, 1000, 1700, and 2000 m.sup.2/g as measured by the BET
method and an average particle size of 400 .mu.m (four prototypes
prepared by changing the specific surface area of Kuraraycoal GGS
manufactured by Kuraray Chemical Co., Ltd., through the change of
the activation conditions) were provided. A menthol flavorant
(manufactured by Fuji Flavor Co., Ltd.) was sorbed to the coconut
shell activated charcoal to saturation, thereby preparing four
types of menthol-sorbed activated charcoals.
[0047] 50 mg of the particles of the menthol-sorbed activated
charcoal thus obtained was dispersed in one of two cellulose
acetate filter materials. These two filter materials were wrapped
with a plug wrapper to form a column, thereby making a segmented
filter. This filter was butted to the end of a tobacco rod (without
menthol flavoring) such that the filter material containing the
menthol-sorbed activated charcoal particles was positioned at the
tobacco rod side. Subsequently, the whole circumference surface of
the filter and the circumference surface of the tobacco rod near
the butted portion were wrapped by a tipping paper. Thus, four
types of filter-tipped cigarettes were fabricated.
[0048] The amount of menthol in tobacco smoke during smoking of the
filter-tipped cigarettes thus obtained, in the initial stage
(without storage), was measured by the following method, thereby
examining the menthol releasability. In addition, the amount of
menthol in tobacco smoke during smoking after storage for 0.5, 1.5,
and 2.5 months was measured by the following method, and the amount
of menthol (relative value) with reference to the value after
storage for 0.5 month was determined. Furthermore, the rate of
occurrence of stains on the cigarette paper was studied by the
following method.
[0049] (Measurement of the Amount of Menthol)
[0050] The filter-tipped cigarette in the initial stage after
production, and the filter-tipped cigarettes after storage for 0.5,
1.5, and 2.5 months were burned using an automatic smoking machine
at a puff volume of 35 mL/2 sec, a puff interval of 60 seconds, and
a burning length of 35 mm from the tip of mouthpiece. During
burning, the particle phase components in the tobacco smoke were
collected using a Cambridge Filter. The components thus obtained
were solvent-extracted with methanol, and then subjected to gas
chromatography, thereby quantitatively determining the amount of
menthol in tobacco smoke.
[0051] (The Rate of Occurrence of Stains on Cigarette Paper)
[0052] The filter-tipped cigarettes were stored for 1 month in a
constant temperature and humidity bath at a temperature of
22.degree. C. and a relative humidity of 60%. Thereafter, stains
appeared on the cigarette paper of the tobacco rod were visually
observed, and the rate of occurrence of stains was determined. The
stain with a size of 0.9 to 1.8 mm as measured by visual
observation was rated as "small stain", and that with a size of
greater than 1.8 mm as measured by visual observation was rated as
"large stain".
[0053] FIG. 2 shows the amount of menthol in tobacco smoke during
smoking in the initial stage (without storage) of the filter-tipped
cigarettes. FIG. 3 shows the amount of menthol (relative value).
FIG. 4 shows the rate of occurrence of stains on the cigarette
paper. In FIG. 3, curve A shows the relationship between the lapsed
days of storage of the cigarette tipped with the filter
incorporating the menthol-sorbed activated charcoal made from
coconut shell activated charcoal having a specific surface area of
700 m.sup.2/g and the rate of menthol decrease. Curve B shows the
relationship between the lapsed days of storage of the cigarette
tipped with the filter incorporating the menthol-sorbed activated
charcoal made from coconut shell activated charcoal having a
specific surface area of 1000 m.sup.2/g and the rate of menthol
decrease. Curve C shows the relationship between the lapsed days of
storage of the cigarette tipped with the filter incorporating the
menthol-sorbed activated charcoal made from coconut shell activated
charcoal having a specific surface area of 1700 m.sup.2/g and the
rate of menthol decrease. Curve D shows the relationship between
the lapsed days of storage of the cigarette tipped with the filter
incorporating the menthol-sorbed activated charcoal made from
coconut shell activated charcoal having a specific surface area of
2000 m.sup.2/g and the rate of menthol decrease. In FIG. 4, the
upper part of the bars represents "large stain", and the lower part
represents "small stain".
[0054] As is evident from FIG. 2, the cigarettes tipped with the
filters incorporating the menthol-sorbed activated charcoal
comprising activated charcoal having a specific surface area of
1500 to 1700 m.sup.2/g as measured by the BET method release a
greater amount of menthol in tobacco smoke during smoking than the
cigarettes tipped with the filters incorporating the menthol-sorbed
activated charcoal comprising activated charcoal having a specific
surface area of less than 1500 m.sup.2/g, and thus exhibited higher
menthol releasability. However, it is seen that there is little
increase in the amount of menthol in tobacco smoke released during
smoking of the cigarettes tipped with the filters incorporating the
menthol-sorbed activated charcoal comprising activated charcoal
having a specific surface area of more than 1700 m.sup.2/g.
[0055] On the other hand, as is evident from FIG. 3, the change in
menthol releasability over time (the decrease in the amount of
menthol) was almost the same among the cigarettes tipped with the
filters incorporating the menthol-sorbed activated charcoal
comprising highly activated charcoal having a specific surface area
of 700 to 1700 m.sup.2/g. However, the amount of menthol (relative
value) released from the cigarette tipped with the filter
incorporating the menthol-sorbed activated charcoal comprising
activated charcoal having a specific surface area of more than 1700
m.sup.2/g (2000 m.sup.2/g) rapidly increased (curve D).
[0056] Furthermore, as is evident from FIG. 4, the rate of
occurrence of stains on the cigarette paper of the tobacco rod was
equal independent of the specific surface area of activated
charcoal in the menthol-sorbed activated charcoal.
[0057] Based on the above results of Test I, it was found that the
use of the filter containing menthol-sorbed activated charcoal with
highly activated charcoal having a specific surface area of 1500
m.sup.2/g or more but 1700 m.sup.2/g or less as measured by the BET
method is suitable for the achievement of a filter-tipped cigarette
which shows a little change in menthol over time and a low rate of
occurrence of stains on cigarette paper during storage, while
realizing a high releasability of menthol.
[0058] <Test II>
[0059] Coconut shell activated charcoal having a specific surface
area of 1700 m.sup.2/g as measured by the BET method and an average
particle size of 400 .mu.m (prototype prepared by changing the
specific surface area of Kuraraycoal GGS manufactured by Kuraray
Chemical Co., Ltd., through the change of the activation
conditions) was provided. A menthol flavorant (manufactured by Fuji
Flavor Co., Ltd.) was sorbed to the coconut shell activated
charcoal at the sorption rates of 80 to 100% with reference to the
saturated amount of menthol for the coconut shell activated
charcoal, thereby preparing six particulate menthol-sorbed
activated charcoals. The saturated amount of menthol for the
coconut shell activated charcoal having a specific surface area of
1700 m.sup.2/g as measured by the BET method and an average
particle size of 400 .mu.m is 60 parts by weight of menthol with
reference to 100 parts by weight of activated charcoal. Therefore,
the sorption rate was defined as follows: activated
charcoal:menthol=100:48 to 60.
[0060] Filter-tipped cigarettes were made using the menthol-sorbed
activated charcoal obtained above in the same manner as in Test I.
The amount of menthol in tobacco smoke during smoking released from
the filter-tipped cigarettes in the initial stage (without storage)
was measured in the same manner as in Test I. The results are shown
in FIG. 5. The amount of menthol on the ordinate in FIG. 5 was
standardized with the amount of menthol from the cigarette
including the menthol-sorbed activated charcoal having a sorption
rate of 100% as 1.
[0061] As is evident from FIG. 5, the amount of menthol in tobacco
smoke during smoking increased as the sorption rate of the
menthol-sorbed activated charcoal approached 100%, and the menthol
was hardly released during smoking when the menthol-sorbed
activated charcoal having a sorption rate of less than 80% was
used.
[0062] <Test III>
[0063] Coconut shell activated charcoal having a specific surface
area of 1700 m.sup.2/g as measured by the BET method and an average
particle size of 400 .mu.m (prototype prepared by changing the
specific surface area of Kuraraycoal GGS manufactured by Kuraray
Chemical Co., Ltd., through the change of the activation
conditions) was provided. A menthol flavorant (manufactured by Fuji
Flavor Co., Ltd.) was sorbed to the coconut shell activated
charcoal at sorption rates of 92, 95, and 100% with reference to
the saturated amount of menthol for the coconut shell activated
charcoal, thereby preparing three particulate menthol-sorbed
activated charcoal.
[0064] Filter-tipped cigarettes were made using the menthol-sorbed
activated charcoal obtained above, in the same manner as in Test I.
These filter-tipped cigarettes were measured for the amount of
menthol in tobacco smoke during smoking after storage for 0.5, 1.5,
2.5, and 3.5 months under high temperature conditions (maximum
temperature 55.degree. C., humidity 35% RH) in the same manner as
in Test I, and the amount of menthol (relative value) was
determined, setting the value after storage for 0.5 month as 100%.
The results are shown in FIG. 6. In FIG. 6, .smallcircle.
represents the change in the amount of menthol (relative value)
over time in tobacco smoke from the cigarette containing
menthol-sorbed activated charcoal having a sorption rate of 92%,
.quadrature. represents the change in the amount of menthol
(relative value) over time in tobacco smoke from the cigarette
containing menthol-sorbed activated charcoal having a sorption rate
of 95%, and .DELTA. represents the change in the amount of menthol
(relative value) over time in tobacco smoke from the cigarette
containing menthol-sorbed activated charcoal having a sorption rate
of 100%.
[0065] As is evident from FIG. 6, in the cigarettes including the
menthol-sorbed activated charcoal having sorption rates of 95 and
100%, the amount of menthol in tobacco smoke during smoking after
storage for 31/2 months under the high temperature conditions was
60 and 50% with reference to that after storage for 0.5 month,
indicating that menthol in tobacco smoke markedly deteriorates over
time.
[0066] On the other hand, it is seen that in the cigarette
including the menthol-sorbed activated charcoal having a sorption
rate of 92%, the amount of menthol in tobacco smoke was kept at
about 85% even after storage for 3.5 months under the high
temperature conditions with reference to the amount of menthol in
tobacco smoke during smoking at the time of 0.5 month storage.
[0067] Based on the above results of Tests II and III, it was found
that the use of the filter containing the menthol-sorbed activated
charcoal in which menthol is sorbed to highly activated charcoal
having a specific surface area at a sorption rate of 80% or more
and 92% or less with reference to the saturated amount of menthol
for the highly activated charcoal is suitable for providing a
filter-tipped cigarette which shows a little change in menthol over
time during storage, which realizing a high releasability of
menthol.
[0068] Examples of the present invention are described below.
EXAMPLE 1
[0069] Coconut shell activated charcoal having a specific surface
area of 1700 m.sup.2/g as measured by the BET method and an average
particle size of 400 .mu.m (prototype prepared by changing the
specific surface area of Kuraraycoal GGS manufactured by Kuraray
Chemical Co., Ltd., through the change of the activation
conditions) was provided. A menthol flavorant (manufactured by Fuji
Flavor Co., Ltd.) was sorbed to the coconut shell activated
charcoal at a sorption rate of 92% with reference to the saturated
amount of menthol for the coconut shell activated charcoal, thereby
preparing particulate menthol-sorbed activated charcoal. The
saturated amount of menthol for the coconut shell activated
charcoal having a specific surface area of 1700 m.sup.2/g as
measured by the BET method and an average particle size of 400
.mu.m is 60 parts by weight of menthol with reference to 100 parts
by weight of activated charcoal. Therefore, the sorption rate of
92% was achieved using 100 parts by weight of activated charcoal
and 55 parts by weight of menthol.
[0070] A filter-tipped cigarette was made using 160 mg of the
menthol-sorbed activated charcoal thus obtained, in the same manner
as in Test I.
COMPARATIVE EXAMPLE 1
[0071] A filter-tipped cigarette was made in the same manner as in
Test I, except that 4.0 mg of menthol was sorbed to the cut tobacco
in the tobacco rod, instead of placing the menthol-sorbed activated
charcoal in the filter.
[0072] The filter-tipped cigarettes of Example 1 and Comparative
Example 1 were measured for the amount of menthol in tobacco smoke
during smoking in the initial stage after production (without
storage), in the same manner as in Test I. As a result, the amount
of menthol in tobacco smoke from the cigarette of Example 1 was
0.41 mg/cig, and the amount of menthol in tobacco smoke from the
cigarette of Comparative Example 1 was 0.4 mg/cig.
[0073] Furthermore, the filter-tipped cigarettes of Example 1 and
Comparative Example 1 were measured for the amount of menthol in
tobacco smoke during smoking after storage for 1, 5, and 9 weeks
under high temperature conditions (maximum temperature 55.degree.
C., humidity 35% RH), in the same manner as in Test I. The results
are shown in FIG. 7. In FIG. 7, .smallcircle. represents the change
over time in the amount of menthol in tobacco smoke from the
cigarette of Example 1, and .quadrature. represents the change over
time in the amount of menthol in tobacco smoke from the cigarette
of Comparative Example 1.
[0074] As is evident from FIG. 7, the cigarette of Example 1 showed
a significantly smaller change over time in the amount of menthol
in tobacco smoke in comparison with the cigarette of Comparative
Example 1.
[0075] Furthermore, the filter-tipped cigarettes of Example 1 and
Comparative Example 1 were stored in a constant temperature and
humidity bath at a temperature of 22.degree. C. and a relative
humidity of 60% for one month, and stains occurred on the cigarette
paper of the tobacco rod were visually observed, and the rate of
occurrence of stains was determined. The stain with a size of 0.9
to 1.8 mm as measured by visual observation was rated as "small
stain", and that with a size of greater than 1.8 mm as measured by
visual observation was rated as "large stain". The results are
shown in FIG. 8. In FIG. 8, the upper part of the bars represents
"large stain", and the lower part represents "small stain".
[0076] As is evident from FIG. 8, the cigarette of Example 1 showed
a significantly lower rate of occurrence of stains on the cigarette
paper of the tobacco rod than that of the cigarette of Comparative
Example 1.
EXAMPLE 2
[0077] The same menthol-sorbed activated charcoal (sorption rate
92%) as in Example 1 was provided, and a filter-tipped cigarette
was made in the same manner as in Test I using 80 mg of the
menthol-sorbed activated charcoal.
COMPARATIVE EXAMPLE 2
[0078] A filter-tipped cigarette was made in the same manner as in
Test I, except that 6.0 mg of menthol was sorbed to the cut tobacco
in the tobacco rod, instead of placing menthol-sorbed activated
charcoal in the filter.
[0079] The filter-tipped cigarettes of Example 2 and Comparative
Example 2 were stored for 1.5 months in a constant temperature and
humidity bath at a temperature of 22.degree. C. and a relative
humidity of 60%, and then the change in the amount of menthol by
the puff number was measured by the following method.
[0080] More specifically, the filter-tipped cigarette after storage
was mounted on an automatic smoking machine, puffed for 2 seconds,
and the particle phase components in the puff were collected using
Cambridge Filter. The component thus obtained was extracted with a
methanol solvent, and then subjected to gas chromatography, thereby
determining the amount of menthol in the puff. The puffing was
performed seven times in total at intervals of one minute, and the
amount of menthol in each puff was determined. The menthol ratio
(%) in each puff was determined by summing the amount of menthol in
the first to seventh puffs, and dividing the amount of menthol in
each puff with the total amount of menthol. The results are shown
in FIG. 9. In FIG. 9, .smallcircle. represents the change in the
ratio of menthol by the puff number of the cigarette of Example 2,
and .quadrature. represents the change in the ratio of menthol by
the puff number of the cigarette of Comparative Example 2.
[0081] As is evident from FIG. 9, the cigarette of Example 2
including the filter containing dispersed menthol-sorbed activated
charcoal released menthol from the initial puff on the same level
with the cigarette of Comparative Example 2 including
menthol-sorbed cut tobacco. More specifically, since the cigarette
of Comparative Example 2 includes menthol sorbed on cut tobacco, it
efficiently releases menthol from the first puff, but stains occur
on the cigarette paper at a high rate as shown by Comparative
Example 1 in FIG. 8 described above. On the other hand, since the
cigarette of Example 2 contains menthol-sorbed activated charcoal
dispersed in the filter, it significantly decreases the rate of
occurrence of stains on the cigarette paper of the tobacco rod, and
efficiently releases menthol from the first puff on the same level
as Comparative Example 2.
[0082] The present invention provides menthol-sorbed activated
charcoal which stably holds menthol during storage and smoothly
releases menthol only during passage of tobacco smoke, and a
cigarette filter containing the menthol-sorbed activated
charcoal.
[0083] The present invention also provides a filter-tipped
cigarette which includes the filter, stably holds menthol over time
during storage in the menthol-sorbed activated charcoal in the
filter, smoothly releases menthol only when tobacco smoke passes
through the filter during smoking, and reduces the occurrence of
stains on the cigarette paper.
* * * * *