U.S. patent application number 17/363801 was filed with the patent office on 2021-10-21 for filter for smoking article.
This patent application is currently assigned to JAPAN TOBACCO INC.. The applicant listed for this patent is JAPAN TOBACCO INC.. Invention is credited to Michihiro INAGAKI, Hiroyuki KUBOTA, Toshitaka UMETSU.
Application Number | 20210321667 17/363801 |
Document ID | / |
Family ID | 1000005738241 |
Filed Date | 2021-10-21 |
United States Patent
Application |
20210321667 |
Kind Code |
A1 |
KUBOTA; Hiroyuki ; et
al. |
October 21, 2021 |
FILTER FOR SMOKING ARTICLE
Abstract
The present invention addresses the problem of providing a
filter for a smoking article that can reduce a stimulus component
such as formaldehyde, and that does not reduce any more than
necessary a component affecting the smoke flavor included in
mainstream smoke. This problem is solved by providing a smoking
article filter comprising a filter segment that has a porous
material containing: a hydrotalcite particle; and a nonfibrous
binder resin.
Inventors: |
KUBOTA; Hiroyuki; (Tokyo,
JP) ; INAGAKI; Michihiro; (Tokyo, JP) ;
UMETSU; Toshitaka; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JAPAN TOBACCO INC. |
Tokyo |
|
JP |
|
|
Assignee: |
JAPAN TOBACCO INC.
Tokyo
JP
|
Family ID: |
1000005738241 |
Appl. No.: |
17/363801 |
Filed: |
June 30, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2020/002586 |
Jan 24, 2020 |
|
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17363801 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/16 20130101; A24D
3/062 20130101; A24D 3/10 20130101; A24D 3/14 20130101 |
International
Class: |
A24D 3/16 20060101
A24D003/16; A24D 3/10 20060101 A24D003/10; A24D 3/06 20060101
A24D003/06; A24D 3/14 20060101 A24D003/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 25, 2019 |
JP |
2019-010764 |
Claims
1. A filter for a smoking article, the filter comprising a filter
segment including a porous material containing a hydrotalcite
particle and a nonfibrous binder resin.
2. The filter for a smoking article according to claim 1, wherein
the porous material further contains a cellulose particle.
3. The filter for a smoking article according to claim 2, wherein
the hydrotalcite particle and the cellulose particle are in a
weight ratio of from 10:90 to 30:70.
4. The filter for a smoking article according to claim 1, wherein
the hydrotalcite particle is formed of a hydrotalcite compound
represented by the formula (1):
M.sup.2+.sub.1-xM.sup.3+.sub.x(OH).sub.2(A.sup.n-).sub.x/n.mH.sub.2O
(1) wherein M.sup.2+ is a divalent metal ion selected from the
group consisting of Mg, Zn, Ni, and Ca, M.sup.3+ is Al ion,
A.sup.n- is an anion having a valency of n and selected from the
group consisting of CO.sub.3, SO.sub.4, OOC--COO, Cl, Br, F,
NO.sub.3, Fe(CN).sub.6.sup.3-, Fe(CN).sub.6.sup.4-, phthalic acid,
isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and
derivatives thereof, malic acid, salicylic acid, acrylic acid,
adipic acid, succinic acid, citric acid and sulfonic acid,
0.1<x<0.4, and 0<m<2.
5. The filter for a smoking article according to claim 1, wherein
the hydrotalcite particle has a mean particle diameter of from 200
to 800 .mu.m.
6. The filter for a smoking article according to claim 1, wherein
the nonfibrous binder resin is a thermoplastic resin.
7. The filter for a smoking article according to claim 1, wherein
the filter segment including the porous material containing the
hydrotalcite particle and the nonfibrous binder resin includes no
plasticizer.
8. The filter for a smoking article according to claim 1, wherein
the hydrotalcite particle and the nonfibrous binder resin are at a
weight ratio of from 70:30 to 80:20 in the porous material.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of PCT International
Application No. PCT/JP2020/002586, filed on Jan. 24, 2020, which is
claiming priority of Japanese Patent Application No. 2019-010764,
filed on Jan. 25, 2019, all of which are hereby expressly
incorporated by reference into the present application.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a filter for a smoking
article.
Background Art
[0003] Research and development have been actively conducted to
provide filters with a function of removing, during smoking, only
unnecessary components out of the components contained in tobacco
smoke, or a function of imparting specific flavor and taste to
tobacco smoke when using a filter cigarette.
[0004] As a means for achieving this, it is known to prepare a
porous substance including a material for adjusting the components
contained in tobacco smoke and use the porous substance as a
constituent material of the filter (see, for example, Patent
Document 1 to 3).
[0005] Materials for adjusting components contained in tobacco
smoke are exemplified by active particles (Patent Document 1 to
3).
[0006] Also known is a cigarette filter having a filter plug
including a filter material in which filtration rate controlling
particles selected from cellulose particles, cellulose triacetate
particles, and mixtures thereof are dispersed in a tow of cellulose
acetate fibers (Patent Document 4).
CITATION LIST
Patent Document
[Patent Document 1] Japanese Translation of PCT Application No.
2016-510993
[Patent Document 2] Japanese Translation of PCT Application No.
2014-509833
[Patent Document 3] Japanese Patent Application Publication No.
2013-215196
[Patent Document 4] Japanese Translation of PCT Application No.
2016-510995
SUMMARY OF THE INVENTION
Technical Problem
[0007] When a porous substance including active particles described
in Patent Document 1 to 3 is used as a constituent material of a
filter, irritating components such as carbon monoxide, phenol and
formaldehyde in tobacco smoke can be reduced but other mainstream
smoke components are also reduced.
[0008] Further, with the filter material described in Patent
Document 4, since the filtration rate controlling particles such as
cellulose particles are dispersed inside the tow of cellulose
acetate fibers and the occupation ratio of the tow of cellulose
acetate fibers in the filter is large, the mainstream smoke
components may be reduced more than necessary.
[0009] As indicated above, according to the techniques described in
Patent Document 1 to 4, in addition to irritating components such
as carbon monoxide, phenol and formaldehyde, the mainstream smoke
components are also reduced. As a result, the user may not be able
to enjoy smoking fully.
[0010] With the foregoing in view, the present invention provides a
filter for a smoking article or the like which can reduce
irritating components, such as formaldehyde, and does not reduce
more than necessary the components affecting the flavor and taste
in mainstream smoke.
Solution to Problem
[0011] As a result of intensive research by the inventors of the
present invention, it has been found that the abovementioned
problem can be resolved by a filter for a smoking article, the
filter comprising a filter segment including a porous material
containing a hydrotalcite particle and a nonfibrous binder
resin.
[0012] Thus, the present invention is as follows.
[1] A filter for a smoking article, the filter comprising a filter
segment including a porous material containing a hydrotalcite
particle and a nonfibrous binder resin. [2] The filter for a
smoking article according to [1], wherein the porous material
further contains a cellulose particle. [3] The filter for a smoking
article according to [2], wherein the hydrotalcite particle and the
cellulose particle are in a weight ratio of from 10:90 to 30:70.
[4] The filter for a smoking article according to any one of [1] to
[3], wherein the hydrotalcite particle is formed of a hydrotalcite
compound represented by the formula (1):
M.sup.2+.sub.1-xM.sup.3+.sub.x(OH).sub.2(A.sup.n-).sub.x/n.mH.sub.2O
(1)
wherein M.sup.2+ is a divalent metal ion selected from the group
consisting of Mg, Zn, Ni, and Ca, M.sup.3+ is Al ion, A.sup.n- is
an anion having a valency of n and selected from the group
consisting of CO.sub.3, SO.sub.4, OOC--COO, Cl, Br, F, NO.sub.3,
Fe(CN).sub.6.sup.3-, Fe(CN).sub.6.sup.4-, phthalic acid,
isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and
derivatives thereof, malic acid, salicylic acid, acrylic acid,
adipic acid, succinic acid, citric acid and sulfonic acid,
0.1<x<0.4, and 0<m<2. [5] The filter for a smoking
article according to any one of [1] to [4], wherein the
hydrotalcite particle has a mean particle diameter of from 200 to
800 .mu.m. [6] The filter for a smoking article according to any
one of [1] to [5], wherein the nonfibrous binder resin is a
thermoplastic resin. [7] The filter for a smoking article according
to any one of [1] to [6], wherein the filter segment including the
porous material containing the hydrotalcite particle and the
nonfibrous binder resin includes no plasticizer. [8] The filter for
a smoking article according to any one of [1] to [7], wherein the
hydrotalcite particle and the nonfibrous binder resin are at a
weight ratio of from 70:30 to 80:20 in the porous material.
Effects of Invention
[0013] According to the present invention, there is provided a
filter for a smoking article or the like which can reduce
irritating components, such as formaldehyde, and does not reduce
more than necessary the components affecting the flavor and taste
in mainstream smoke.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagram showing measurement results of a ratio
of a permeation amount of semi-volatile components normalized by a
crude tar amount.
[0015] FIG. 2 is a diagram showing measurement results of a
permeation amount of formaldehyde normalized by a crude tar
amount.
[0016] FIG. 3 is a schematic diagram showing an example of an
embodiment of a filter for a smoking article.
[0017] FIG. 4 is a schematic diagram showing another example of an
embodiment of a filter for a smoking article.
[0018] FIG. 5 is a schematic diagram showing an apparatus for
measuring formaldehyde.
DESCRIPTION OF THE EMBODIMENTS
[0019] Hereinafter, the present invention will be described in
detail with reference to embodiments, examples, and the like, but
the present invention is not limited to the following embodiments
and examples, and the like and may be implemented while being
arbitrarily changed without departing from the gist of the present
invention.
[0020] <Hydrotalcite Particle>
[0021] A filter for a smoking article according to an embodiment of
the present invention includes a filter segment including a porous
material containing a hydrotalcite particle and a nonfibrous binder
resin.
[0022] The hydrotalcite particle is completely different in
properties from the active particles described in the
above-mentioned Patent Document 1 to 3.
[0023] Specifically, while the active particles described in Patent
Document 1 to 3 have a property of demonstrating adsorptivity or a
property of inducing chemical reactions with respect to components
contributing to flavor and taste, the hydrotalcite particle used in
the embodiment of the present invention has lower ability to adsorb
components contributing to flavor and taste than the active
particles described in Patent Document 1 to 3 and does not induce
chemical reactions with the components contributing to flavor and
taste.
[0024] In addition, the hydrotalcite particle used in this
embodiment has higher ability to adsorb formaldehyde as an
irritating component than cellulose particles described in Patent
Document 4.
[0025] The hydrotalcite particle is a particle of a known compound
having a layered structure similar to that of hydrotalcite; see,
for example, WO 2003/056947.
[0026] Specifically, the hydrotalcite compound constituting the
hydrotalcite particle can be represented by the following formula
(1):
M.sup.2+.sub.1-xM.sup.3+.sub.x(OH).sub.2(A.sup.n-).sub.x/n.mH.sub.2O
(1)
wherein M.sup.2+ is a divalent metal ion selected from the group
consisting of Mg, Zn, Ni, and Ca, M.sup.3+ is Al ion, A.sup.n- is
an anion having a valency of n and selected from the group
consisting of CO.sub.3, SO.sub.4, OOC--COO, Cl, Br, F, NO.sub.3,
Fe(CN).sub.6.sup.3-, Fe(CN).sub.6.sup.4-, phthalic acid,
isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and
derivatives thereof, malic acid, salicylic acid, acrylic acid,
adipic acid, succinic acid, citric acid and sulfonic acid,
0.1<x<0.4, and 0<m<2.
[0027] It is preferable that in the above general formula, M.sup.2+
is a Mg ion, M.sup.3+ is an Al ion, A.sup.n- is CO.sub.3.sup.2- or
SO.sub.4.sup.2-, x is 0.1<x<0.4, m is 0<m<2. Such
Mg--Al hydrotalcite compound is stable when x is in the range of
from 0.20 to 0.33. The above general formula is most preferably
Mg.sub.6Al.sub.2(OH).sub.16CO.sub.3.4H.sub.2O.
[0028] The Mg--Al hydrotalcite compound can be manufactured by
adding an alkali carbonate or an alkali carbonate and a caustic
alkali to an aqueous solution of a water-soluble aluminum salt
selected from aluminum sulfate, aluminum acetate and alum, or
aluminic acid and a water-soluble magnesium salt, and conducting a
reaction while keeping the pH of the reaction mixture at 8.0 or
more. The obtained hydrotalcite compound can be pulverized and
classified to obtain particles of the hydrotalcite compound.
[0029] The hydrotalcite particles can be granulated, classified,
and processed to a preferable particle diameter. As a granulation
method, granulation by extrusion molding or compression molding is
preferable because particles having a BET specific surface area of
500 m.sup.2/g or less are easily formed. In particular, granulation
by extrusion molding is preferable because particles having a BET
specific surface area of 100 m.sup.2/g or less are easily
formed.
[0030] The BET specific surface area of the hydrotalcite particles
is preferably from 1 to 200 m.sup.2/g.
[0031] The average particle diameter of the hydrotalcite particles
is preferably from 200 to 800 .mu.m. This average particle diameter
is an average of secondary particles of hydrotalcite particles.
Such particle diameter contributes to good adsorption to
semi-volatile components. The average particle diameter can be
measured using an image analysis-type particle size distribution
measuring device (for example, Camsizer X2 manufactured by Retsch
Technology).
[0032] The "components contributing to flavor and taste", as
referred to herein, are semi-volatile components contained in
tobacco smoke, and can be more specifically exemplified by
limonene, 2,5-dimethylpyrazine, 3-vinylpyridine, 3-butylpyridine,
phenylethyl alcohol, and indole.
[0033] The hydrotalcite particle according to the embodiment of the
present invention, when used in a filter for a smoking article,
does not selectively reduce any component contributing to flavor
and taste, specifically, the abovementioned semi-volatile
components, relative to crude tar in tobacco smoke.
[0034] The porous material included in the filter segment according
to the embodiment of the present invention may include a cellulose
particle in addition to the hydrotalcite particle.
[0035] The cellulose particle can be prepared by compression
molding a commercially available cellulose powder such as
microcrystalline cellulose as a raw material by a compression type
granulating apparatus, pulverizing the obtained molded body and
classifying. The cellulose particle can be made with reference to
WO 2013/084661. Alternatively, a commercially available cellulose
molded body may be used.
[0036] The cellulose particles may have a volume-based median
diameter (D50) of from 100 to 1700 .mu.m, preferably 200 to 1500
.mu.m, and more preferably 300 to 1300 .mu.m.
[0037] The median diameter (D50) can be measured with a laser
diffraction/scattering type particle diameter distribution
(granulometric distribution) measuring device.
[0038] The bulk density of the cellulose particles may be from 0.05
to 1.00 g/cc, preferably 0.10 to 0.90 g/cc, and more preferably
0.15 to 0.85 g/cc.
[0039] The bulk density of the cellulose particles can be measured
with, for example, a Powder Characteristics Tester PT-X
manufactured by Hosokawa Micron Corporation.
[0040] The BET specific surface area of the cellulose particle is
preferably 10 m.sup.2/g or less, and more preferably equal to or
less than the detection limit. The lower limit of the BET specific
surface area of the cellulose particle may be more than 0
m.sup.2/g, for example.
[0041] Like the above-mentioned hydrotalcite particle, the
cellulose particle has the ability not to selectively reduce the
semi-volatile components contained in tobacco smoke relative to
crude tar of tobacco smoke.
[0042] When the cellulose particle is used in combination with the
hydrotalcite particle, it is possible to design the desired flavor
and taste produced by tobacco smoke by adjusting the compounding
ratio of the particles, without adjusting the length of the filter
segment including the particles.
[0043] When the above hydrotalcite particle and cellulose particle
are used in combination, the weight ratio thereof is preferably
from 10:90 to 30:70, and more preferably from 10:90 to 20:80.
[0044] Also, it is preferable that the cellulose particle have a
particle diameter of from 10 to 70 mesh based on JIS Z 8801-1
(2006). Within such a particle diameter range, cellulose particles
can be evenly present inside the porous material, and contribution
is made to not selectively reducing the semi-volatile
component.
[0045] The hydrotalcite particle and cellulose particle are
thermally stable at 150.degree. C. "Thermally stable", as referred
to herein, means that the ability of not selectively reducing
components contributing to flavor and taste relative to crude tar
in tobacco smoke before heating to 150.degree. C. is not different
from that after the heating, and that the particles do not deform
when heated to 150.degree. C.
[0046] Conventionally, it was not thought that hydrotalcite
particles are very resistant to heat, but the inventors of the
present invention have found that hydrotalcite particles do not
lose their properties even when heated to 150.degree. C.
[0047] In addition to the hydrotalcite particle, the porous
material of the filter segment according to the embodiment of the
present invention may or may not include other inert particles
together with the cellulose particle or instead of the cellulose
particle, within the range in which the effect of the present
invention is not impaired.
[0048] In the present specification, the wording "not selectively
reducing relative to crude tar in tobacco smoke" means that the
delivery amount of semi-volatile components normalized by a crude
tar amount which is determined by the below-described method for
measuring the delivery amount of semi-volatile components, which is
performed with respect to the filter for a smoking article
according to the embodiment of the present invention, is generally
larger than that of the below-described typical filter for a
smoking article.
[0049] A filter (airflow resistance is 85 mmH.sub.2O/27 mm)
including about 7% by weight of triacetin as a plasticizer in a
cellulose acetate fiber bundle is used as a typical (control)
filter.
[0050] (Smoking Test)
[0051] The permeation amount (delivery amount) of a semi-volatile
component is measured as follows.
[0052] Automatic smoking is performed using an automatic smoking
device (RM20D, manufactured by Borgwaldt KC Inc.) under the
conditions of a suction capacity of 35.0 mL/2 sec, a suction time
of 2 sec/puff, and a suction frequency of 1 puff/min, the crude tar
is collected using a Cambridge filter (CM-133, manufactured by
Borgwaldt KC Inc.), and the smoke passing through the Cambridge
filter is collected in 10 mL of methanol cooled to -70.degree. C.
with a coolant composed of dry ice and isopropanol. Further, d-32
pentadecane as an internal standard substance is contained in the
methanol solution at a concentration of 5 .mu.g/mL.
[0053] The Cambridge filter that collected the crude tar and 10 mL
of the methanol solution that collected the cigarette smoke are
transferred to a serum bottle and shaken for 30 min. After shaking,
the supernatant is collected and used as an analytical sample.
[0054] The analytical sample is analyzed by gas chromatograph mass
spectrometry (GC-MSD). Agilent 7890A (Agilent Technologies Inc.) is
used for GC and Agilent 5975C (Agilent Technologies Inc.) is used
for MSD.
[0055] <Binder Resin>
[0056] The porous material of the filter segment of the filter for
a smoking article according to the embodiment of the present
invention includes a nonfibrous binder resin. "Nonfibrous", as
referred to herein, means that the resin is not fibrous like a
cellulose acetate tow.
[0057] As the binder resin, for example, a thermoplastic resin can
be mentioned.
[0058] Examples of the thermoplastic resin include, but are not
limited to, polyolefins, polyesters, polyamides (or nylon),
polyacrylates, polystyrene, polyvinyl, polytetrafluoroethylene
(PTFE), polyether ether ketone (PEEK), copolymers thereof,
derivatives thereof, combinations thereof, and the like. Examples
of polyolefins include, but are not limited to, polyethylene,
polypropylene, polybutylene, polymethylpentene, copolymers thereof,
derivatives thereof, combinations thereof, and the like. Examples
of suitable polyethylene further include low-density polyethylene,
linear low-density polyethylene, high-density polyethylene,
copolymers thereof, derivatives thereof, combinations thereof, and
the like.
[0059] Examples of suitable polyesters include polyethylene
terephthalate, polybutylene terephthalate,
polycyclohexylenedimethylene terephthalate, polytrimethylene
terephthalate, copolymers thereof, derivatives thereof,
combinations thereof, and the like.
[0060] Examples of suitable polyacrylates include, but are not
limited to, polymethyl methacrylate, copolymers thereof,
derivatives thereof, combinations thereof, and the like.
[0061] Examples of suitable polystyrenes include, but are not
limited to, polystyrene, acrylonitrile butadiene styrene, styrene
acrylonitrile, styrene butadiene, styrene maleic anhydride,
copolymers thereof, derivatives thereof, combinations thereof, and
the like.
[0062] Examples of suitable polyvinyls include, but are not limited
to, ethylene vinyl acetate, ethylene vinyl alcohol, polyvinyl
chloride, copolymers thereof, derivatives thereof, combinations
thereof, and the like.
[0063] In the embodiment of the present invention, it is preferable
to use at least one of polyethylene, a copolymer of polyethylene, a
derivative of polyethylene, and a combination thereof as the binder
resin.
[0064] Polyethylene can be exemplified by GUR (registered
trademark) polymers marketed by Celanese Corporation such as GUR
(registered trademark) 2000 series (2105, 2122, 2122-5, 2126), GUR
(registered trademark) 4000 series (4120, 4130, 4150, 4170, 4012,
4122-5, 4022-6, 4050-3/4150-3), GUR (registered trademark) 8000
series (8110, 8020), and GUR (registered trademark) X series (X143,
X184, X168, X172, X192).
[0065] The melt flow rate of the binder resin used in the
embodiment of the present invention is preferably 3.5 g/10 min or
less and more preferably 2.0 g/10 min or less at 190.degree. C. and
15 kg.
[0066] The binder resin used in the embodiment of the present
invention can be in the form of particles. The particles can be in
the form of powder, pellets or fine particles.
[0067] When the binder resin is in the form of particles, the range
of the diameter thereof may be from about 0.1 nm to 5000 .mu.m,
preferably from about 10 nm to 500 .mu.m, and more preferably from
about 100 nm to 300 .mu.m.
[0068] The binder resin used in the embodiment of the present
invention may have a bulk density of from 0.10 g/cm.sup.3 to 0.55
g/cm.sup.3, preferably from 0.17 g/cm.sup.3 to 0.50 g/cm.sup.3, and
more preferably from 0.20 g/cm.sup.3 to 0.47 g/cm.sup.3.
[0069] <Porous Material>
[0070] A porous material according to the embodiment of the present
invention is a constituent element of at least one filter segment
constituting the filter for a smoking article according to the
embodiment of the present invention.
[0071] The porous material according to the embodiment of the
present invention contains the hydrotalcite particle and the binder
resin described above, and any method can be used for producing the
porous material.
[0072] For example, the hydrotalcite particles (together with, for
example, cellulose particles, if necessary) and the binder resin
are mixed and placed in a mold having an appropriate shape. The
mold is heated to the melting point of the binder resin or above,
for example, in one embodiment to from about 150.degree. C. to
300.degree. C., and held for sufficient time and at sufficient
temperature to heat the mold and the contents thereof to a desired
temperature.
[0073] The substance is thereafter taken out of the mold and cooled
to room temperature, thereby producing a porous material having
voids formed therein.
[0074] The void volume ratio of the porous material can be, for
example, from 40% to 90%, and the void volume ratio can be
calculated on the basis of the description of Patent Document 2.
The shape of the porous material is not particularly limited but
can be exemplified by a cylindrical shape. The length of the porous
material in the airflow direction is not particularly limited and
can be exemplified by from about 3 to 30 mm.
[0075] In the filter segment having the porous material according
to the embodiment of the present invention, since the hydrotalcite
particle is fixed in the porous material by the binder resin, the
hydrotalcite particle does not escape from the filter segment when
the filter segment having the porous material, or a filter for a
smoking article including the filter segment, or a smoking article
including the filter for a smoking article is transported.
[0076] Further, since the filter for a smoking article according to
the embodiment of the present invention is provided with the filter
segment having the porous material, the filtration rate of tar and
nicotine per airflow resistance of the filter is lowered (delivery
to the user is facilitated). In addition, it is possible to design
a filter for a smoking article having a high ventilation rate at a
low filtration rate when the amount of tar during smoking is made
constant, and the amount of generated carbon monoxide can be
reduced.
[0077] In the porous material according to the embodiment of the
present invention, it is preferable that the hydrotalcite particle
and the nonfibrous binder resin be at a weight ratio of from 70:30
to 80:20. By including the hydrotalcite particles and the
nonfibrous binder resin in such ranges, it is possible to provide
voids inside the porous material with an appropriate void ratio,
and it is possible to adjust suitably the airflow resistance and
the permeation amount of semi-volatile components in tobacco
smoke.
[0078] Further, in the case where the hydrotalcite particle and the
cellulose particle are used in combination, the weight ratio of the
total weight of these particles and the nonfibrous binder resin is
from 70:30 to 80:20.
[0079] With the porous material according to the embodiment of the
present invention, there is no need to use a plasticizer such as
triacetin which has been used for conventional filters for smoking
articles. This makes it possible to prevent semi-volatile
components in tobacco smoke from being removed by being adsorbed by
the plasticizer.
[0080] <Filter for Smoking Article>
[0081] The filter for a smoking article of the present invention
comprises at least the above-described filter segment having the
porous material (hereinafter also simply referred to as "segment
having the porous material").
[0082] The filter segment having the porous material can have a
circumferential length and a length in the airflow direction
similar to the circumferential length and the length in the airflow
direction of the filter constituting the conventional filter
cigarette.
[0083] For example, the circumferential length can be from 16 to 26
mm and preferably from 24 to 26 mm. This corresponds to the filter
segment diameter of from 5.1 to 8.3 mm and from 7.6 to 8.3 mm,
respectively.
[0084] The filter segment having the porous material may have the
abovementioned circumferential length, but this filter segment is
not limited to the size of the filter included in the conventional
filter cigarette and may also have a circumferential length and a
length in the airflow direction suitable for other smoking articles
to be described hereinbelow.
[0085] The filter segment having the porous material may be wrapped
around the outer circumferential surface thereof with a wrapper for
a filter to be described hereinbelow.
[0086] The filter for a smoking article according to the embodiment
of the present invention may include, in addition to the
above-described filter segment having the porous material, a filter
segment (hereinafter can be also referred to as "conventional
filter segment") constituted by a cellulose acetate tow similar to
that of the filter constituting the conventional filter
cigarette.
[0087] As an example of a configuration according to one
embodiment, the conventional filter segment is arranged at the
suction end side, and the above-described filter segment having the
porous material is arranged between a tobacco rod having a tobacco
cut and the conventional filter segment.
[0088] A filter for a smoking article can be produced by connecting
the filter segment having the porous material and the conventional
filter segment by using molding paper. This configuration is shown
in FIG. 3. This configuration is also referred to as a dual
segment.
[0089] When a dual segment is used, the porous material is not
exposed at the suction end, so that the appearance can be improved.
It is also possible to prevent the porous material from directly
contacting the user's mouth.
[0090] In the configuration according to another possible
embodiment of the present invention, the conventional filter
segment is arranged on the suction end side, the filter segment
having the porous material is arranged so as to be adjacent to the
conventional filter segment, and the conventional filter segment is
further arranged between the filter segment having the porous
material and a tobacco rod having a tobacco cut. This configuration
is shown in FIG. 4. This configuration is also referred to as a
triple segment. When the triple segment is used, it is possible to
prevent the porous material from being deteriorated by the
transmission of high-temperature heat from the tobacco rod side to
the porous material.
[0091] As shown in FIG. 3, the number of filter segments
constituting the filter for a smoking article according to the
embodiment of the present invention may be not only two as shown in
FIG. 3, or three as shown in FIG. 4, but also four or more. In that
case, two or more filter segments each having the porous material
can be provided.
[0092] FIGS. 3 and 4 show the configurations when a filter
cigarette is used as a smoking article, but the smoking article may
be other than a filter cigarette as will be described hereinbelow,
and in this case, the configuration be changed as appropriate.
Thus, an embodiment in which the filter 7 without the tobacco rod
is appropriately used as the filter for a smoking article according
to the embodiment of the present invention in other smoking
articles can be also mentioned.
[0093] It is to be noted that the outer surface of the filter
formed by joining the filter segments may be wrapped with tip
paper.
[0094] In the case where the filter segment is composed of an
acetate tow, the single yarn fineness, total fineness, and
cross-sectional shape of the acetate tow are not particularly
limited.
[0095] The filter segment other than the filter segment having the
porous material may be configured of a material other than the
acetate tow.
[0096] It is possible to design, as appropriate, the adjustment of
airflow resistance and addition of additives (known adsorbents,
flavors, flavor holding materials, and the like) to the acetate tow
or other material.
[0097] Tip paper, molding paper, and wrapper for wrapping the outer
surface of filters used in the conventional filter cigarettes can
be used for the filter for a smoking article according to the
present embodiment. Here, the wrapper is in direct contact with the
porous material or the filter tow or the like and is wrapped in a
cylindrical shape. The molding paper is used to fix a plurality of
filter sections when there is a plurality of filter segments
wrapped with the wrapper. The tip paper is used to connect the
filter for a smoking article to a tobacco rod when the smoking
article has the tobacco rod.
[0098] The tip paper can be provided with ventilation holes for
adjusting the presence ratio of tobacco smoke and air to be inhaled
during smoking of the smoking article (the ventilation holes are
shown by dotted lines in the tip paper shown in FIGS. 3 and 4). The
arrangement of the ventilation holes is not particularly limited.
For example, the ventilation holes can be arranged in one row or
two rows in the circumferential direction of the smoking article.
The pitch of the ventilation holes, the size of the holes, and the
method for opening the holes are not particularly limited.
[0099] <Smoking Articles>
[0100] The filter for a smoking article according to the embodiment
of the present invention can be used for the following smoking
articles.
[0101] A combustion type smoking article in which a tobacco filler
is burned, for example, a filter cigarette; a non-combustion
heating type smoking article in which a tobacco filler is heated
without burning; and a non-heating type smoking article in which
flavor and taste components of a tobacco filler are inhaled without
burning or heating the tobacco filler. The non-combustion heating
type smoking article can be exemplified by a carbon heat source
inhalation device in which a tobacco filler is heated by combustion
heat of a carbon heat source (see, for example, WO 2006/073065); an
electric heating type inhalation device equipped with an inhalation
device and a heating device for electrically heating the inhalation
device (see, for example, WO 2010/110226); and a liquid atomizing
type inhalation device in which a liquid aerosol source including a
flavor and taste source is atomized by heating (see, for example,
WO 2015/046385). Another preferred application is to a
non-combustion heating type smoking article in which an aerosol
generating rod is used instead of a tobacco filler and a flavor
component is generated by heating from the outside of the aerosol
generating rod. Such a smoking article has a battery, an electric
heating unit, and an aerosol generating rod member which is
detachably plugged in. The electric heating unit is a so-called
heater and has a heat generating element. The heat generating
element of the electric heating unit heats the aerosol generating
rod and releases the flavor from the filler of the aerosol
generating rod into the surrounding air. The heating temperature of
the aerosol generating rod by the electric heating unit is, for
example, 400.degree. C. or less. The smoking articles having the
aerosol generating rod member are described in detail in Japanese
Patent No. 4889218 and Japanese Patent No. 4762247.
[0102] The filter for a smoking article according to the embodiment
of the present invention can be used as a filter for these
non-combustion heating type smoking articles.
[0103] A non-heating type smoking article can be exemplified by a
flavor inhalation device which includes a suction holder and a
tobacco filler filled in the main flow path of the suction holder
and in which flavor and taste components of the tobacco filler are
inhaled (see, for example, WO 2010/095659).
[0104] The filter for a smoking article according to the embodiment
of the present invention can be appropriately used in the smoking
articles exemplified hereinabove.
[0105] In this case, the shape of the filter segment having the
porous material, the shape of the filter for a smoking article
including the filter segment, and the like can be changed as
appropriate.
EXAMPLES
[0106] The present invention will be described hereinbelow more
specifically with reference to examples, but the present invention
is not limited to the description of the examples, provided that
the scope of the invention is not exceeded.
Production Example 1
<Preparation of Filter Segment Having Porous Material Containing
Hydrotalcite Particle and Polyethylene Resin>
[0107] A hydrotalcite compound represented by
Mg.sub.6Al.sub.2(OH).sub.16CO.sub.3.4H.sub.2O was used as the
hydrotalcite particle. The hydrotalcite compound product was
pulverized and classified to prepare particles having a particle
diameter of from 250 to 500 .mu.m. Polyethylene was used as the
binder resin.
[0108] The hydrotalcite particles (75 parts by weight) and
polyethylene (GUR (registered trademark) 25 parts by weight,
manufactured by Celanese Corporation) as the binder resin were
mixed, placed in a mold and heated to 200.degree. C. over 40 min.
The material after heating was removed from the mold and cooled to
obtain a porous material 1 having a circumference of 23.75 mm and a
length of 20 mm. The BET specific surface area of the hydrotalcite
particles was 65 m.sup.2/g.
Production Example 2
[0109] A porous material 2 was obtained in the same manner as in
Production Example 1 except that cellulose particles were used
instead of hydrotalcite particles.
[0110] The cellulose particles were produced by using a
commercially available cellulose powder (Endurance MCC VE-090,
manufactured by FMC Corporation) as a raw material, compression
molding by using a compression granulating apparatus (Roller
Compactor TF-208, manufactured by Freund Corporation), pulverizing
and classifying. The cellulose particles had a median diameter
(D50) of 1190 .mu.m, a bulk density of 0.832 g/cc, and a BET
specific surface area equal to or less than the detection limit.
The bulk density was measured with a Powder Characteristics Tester
PT-X manufactured by Hosokawa Micron Corporation.
Production Example 3
[0111] A porous material 3 was obtained in the same manner as in
Production Example 1 except that un-activated carbide particles
were used instead of hydrotalcite particles, the weight thereof was
80 parts by weight and the weight of polyethylene was 20 parts by
weight. The benzene adsorption capacity of the un-activated carbide
particles measured according to JIS K 1474 was 0.6.
[0112] The un-activated carbide particles were obtained by
subjecting coconut shells to carbonization treatment in an inert
gas atmosphere in a carbonization furnace.
Production Example 4
[0113] A porous material 4 was obtained in the same manner as in
Production Example 3 except that low-activated carbon prepared by a
steam activation method was used instead of hydrotalcite particles.
The low-activated charcoal had a BET specific surface area of 725
m.sup.2/g.
Production Example 5
[0114] A porous material 5 was obtained in the same manner as in
Production Example 3 except that activated carbon prepared by a
steam activation method was used instead of hydrotalcite particles.
The activated charcoal had a BET specific surface area of 1142
m.sup.2/g.
Test Example 1: Comparison of Permeation Amounts of Semi-Volatile
Components
[0115] A tobacco rod including a tobacco cut was removed from a
commercially available filter cigarette, and the above-described
porous material (20 mm) as a filter segment and a cellulose acetate
tow filter (7 mm; 5.5Y31000) were successively connected to the
tobacco rod to prepare a filter cigarette for testing.
[0116] As a control, a filter cigarette was prepared by connecting
a cellulose acetate tow filter (27 mm; 2.8Y35000) to the tobacco
rod same as described hereinabove.
[0117] A smoking test was carried out using these filter
cigarettes, and the amount of crude tar and also limonene,
2,5-dimethylpyrazine, 3-vinylpyridine, 3-butylpyridine, phenylethyl
alcohol, and indole as semi-volatile components from among the
components of tobacco smoke were selectively analyzed.
[0118] The smoking test was carried out using the equipment and
conditions described above.
[0119] The results are shown in FIG. 1. The type of semi-volatile
component is indicated on the abscissa in FIG. 1. The ratio of the
amount of the semi-volatile component normalized by the amount of
crude tar in each sample to the control is indicated on the
ordinate in FIG. 1, and a larger value thereof indicates that a
selective reduction has not occurred (the permeation amount is
large).
[0120] It follows from the results shown in FIG. 1 that in the
sample having the porous material using the hydrotalcite particle
as a filter segment, the delivery amount (permeation amount) of
semi-volatile components was substantially equal to or larger than
the control. In the sample using cellulose particles, the
permeation amount (delivery amount) of semi-volatile components was
generally larger than that of the control. In the sample having the
porous material using low-activated carbon or activated carbon as a
filter segment, the permeation amount (delivery amount) of
semi-volatile components was generally smaller than that of the
control.
[0121] These results indicate that the hydrotalcite particle and
cellulose particle have the ability not to selectively reduce the
semi-volatile components relative to the crude tar of tobacco
smoke.
Test Example 2: Comparison of Adsorption Capacity of
Formaldehyde
(Measurement of Amount of Formaldehyde in Mainstream Smoke)
[0122] The amount of formaldehyde in mainstream smoke was measured
by Canadian official method (2,4-DNPH-HPLC method) to determine the
formaldehyde adsorption capacity.
[0123] First, 9.51 g of 2,4-dinitrophenylhydrazine (DNPH) was
heated and dissolved in 1 L of acetonitrile, then 5.6 mL of 60%
perchloric acid was added, and ultrapure water was added to prepare
2 L of a collection solution.
[0124] The outline of the measuring apparatus will be described
with reference to FIG. 5. As shown in FIG. 5, the DNPH collection
solution 13 was placed in the collection gas wash bottle 12. The
volume of the gas wash bottle 12 was 100 mL and the amount of the
DNPH collection solution 13 was 80 mL. The gas wash bottle 12 was
placed in an ice water bath 14 and cooled with ice. The lower end
of a glass tube 15 to which a cigarette 11 was attached was
immersed in the collection solution 13 in the gas wash bottle 12. A
glass tube 16 and a Cambridge pad 17 were attached so as to be in
communication with the dead volume of the gas wash bottle 12, and
the Cambridge pad 17 and an automatic smoking device 18 were
connected.
[0125] The cigarette 11 was attached to the glass tube 15, and the
cigarette 11 was automatically smoked under the standard smoking
condition stipulated by ISO. Thus, for each cigarette, the
operation of sucking 35 mL for 2 sec in one empty puff was repeated
at 58 sec intervals. While mainstream smoke was bubbling,
formaldehyde was derivatized by DNPH. Two cigarettes for
measurement were set. At this time, all the cigarettes using the
particles of the preparation examples were adjusted so that the
pressure loss was the same.
[0126] The derivative thus produced was measured by high
performance liquid chromatography (HPLC). First, the collected
solution was filtered and then diluted with Trizma Base solution (4
mL of collection solution, 6 mL of Trizma Base solution). The
resulting solution was measured by HPLC. The HPLC measurement
conditions are as follows.
Column: HP LiChrospher 100 RP-18 (5.mu.) 250.times.4 mm
[0127] Guard column: HP LiChrospher 100 RP-18 (5.mu.) 4.times.4 mm
Column temperature: 30.degree. C. Detection wavelength: DAD 356 nm
Injection volume: 20 .mu.L Mobile phase: gradient with three phases
(solution A: ultrapure water solution containing 30% of
acetonitrile, 10% of tetrahydrofuran, and 1% of isopropanol;
solution B: ultrapure water solution containing 65% of
acetonitrile, 1% of tetrahydrofuran, and 1% of isopropanol;
solution C: acetonitrile 100%).
[0128] As a control test, the amount of formaldehyde in mainstream
smoke was measured for a cigarette provided with a filter not
containing any particle (hereinafter referred to as control). The
amount of crude tar collected directly on the Cambridge pad was
also measured separately.
[0129] The permeation amount of formaldehyde normalized by the
crude tar amount of was determined by substituting the measured
amount of formaldehyde into the following formula: (Permeation
amount of formaldehyde normalized by crude tar amount)=[{(measured
amount of formaldehyde (.mu.g/cig)/(crude tar amount)
(mg/cig)].
[0130] The results are shown in FIG. 2. It is clear that the
smaller the numerical value on the ordinate in FIG. 2, the smaller
the permeation amount (delivery amount) of formaldehyde per crude
tar and the larger the amount of formaldehyde adsorbed to the
particles contained in the porous material.
[0131] From the results shown in FIG. 2, it was found that when a
porous material containing hydrotalcite particles is used, the
amount of formaldehyde delivered can be kept low, like when using
low-activated carbon and activated carbon.
[0132] From the results of Test Examples 1 and 2, it was found that
the hydrotalcite particle used in the embodiments of the present
invention has the ability not to selectively reduce the
semi-volatile components in tobacco smoke relative to crude tar of
tobacco smoke and also has the ability to selectively reduce
irritating volatile components such as formaldehyde.
[0133] <Evaluation of Sensory Properties>
[0134] For each filter cigarette for testing for which
semi-volatile components were measured, the ventilation ratio and
the tar amount were adjusted to 37% and 10 mg, respectively, and
sensory properties at the time of smoking were evaluated.
[0135] As a result, it was found that in the sample provided with
the filter segment having the porous material including the
hydrotalcite particle, the cellulose particle or the un-activated
carbide particle, the flavor and taste originating from tobacco
smoke increased and irritation decreased. Meanwhile, in the sample
provided with the porous material using the low-activated carbon or
activated carbon, which is an active particle, as a filter segment,
the flavor and taste originating from tobacco smoke decreased.
[0136] From the results obtained in measurement of semi-volatile
components and sensory evaluation, it was confirmed that when using
the filter for a smoking article according to the embodiment of the
present invention, it is possible to cause selective permeation of
semi-volatile components (without the removal thereof by the
filter), thereby making it possible to give the user stronger
flavor and taste inherent to tobacco leaves.
[0137] Further, when the filter for a smoking article according to
the embodiment of the present invention is used, formaldehyde which
is an irritating component can be efficiently reduced.
REFERENCE SIGNS LIST
[0138] 1 Tobacco rod portion [0139] 2 Conventional filter segment
[0140] 3 Filter segment having porous material [0141] 4 Wrapper
[0142] 5 Molding paper [0143] 6 Tip paper [0144] 7 Filter
* * * * *