U.S. patent application number 13/895995 was filed with the patent office on 2013-09-26 for cigarette paper and cigarette reducing visible sidestream smoke amount and carbon monoxide amount in mainstream smoke.
This patent application is currently assigned to Japan Tobacco Inc.. The applicant listed for this patent is Japan Tobacco Inc.. Invention is credited to Nobuyuki ISHIKAWA, Kiyohiro SASAKAWA, Tetsuya YOSHIMURA.
Application Number | 20130247925 13/895995 |
Document ID | / |
Family ID | 46931492 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130247925 |
Kind Code |
A1 |
ISHIKAWA; Nobuyuki ; et
al. |
September 26, 2013 |
CIGARETTE PAPER AND CIGARETTE REDUCING VISIBLE SIDESTREAM SMOKE
AMOUNT AND CARBON MONOXIDE AMOUNT IN MAINSTREAM SMOKE
Abstract
This invention is intended to provide a cigarette paper capable
of reducing both a visible sidestream smoke amount and a carbon
monoxide amount in a mainstream smoke. The invention provides a
cigarette paper having a grammage of 40 to 55 g/m.sup.2 and
containing calcium carbonate in an amount of 18 g/m.sup.2 or more.
Where the primary particles of calcium carbonate having a columnar
shape or a needle shape are used, the carbon monoxide amount in the
mainstream smoke decreases significantly, as compared with the case
where the primary particles of calcium carbonate having another
shape are used.
Inventors: |
ISHIKAWA; Nobuyuki; (Tokyo,
JP) ; YOSHIMURA; Tetsuya; (Tokyo, JP) ;
SASAKAWA; Kiyohiro; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Japan Tobacco Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Japan Tobacco Inc.
Tokyo
JP
|
Family ID: |
46931492 |
Appl. No.: |
13/895995 |
Filed: |
May 16, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2012/058622 |
Mar 30, 2012 |
|
|
|
13895995 |
|
|
|
|
Current U.S.
Class: |
131/331 ;
428/330; 428/342 |
Current CPC
Class: |
Y10T 428/258 20150115;
D21H 17/14 20130101; D21H 17/64 20130101; D21H 17/675 20130101;
D21H 21/52 20130101; A24D 1/02 20130101; Y10T 428/277 20150115;
D21H 17/66 20130101; D21H 15/02 20130101 |
Class at
Publication: |
131/331 ;
428/342; 428/330 |
International
Class: |
A24D 1/02 20060101
A24D001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2011 |
JP |
2011-077902 |
Claims
1. A cigarette paper having a grammage of 40 to 55 g/m.sup.2 and
containing calcium carbonate in an amount of 18 g/m.sup.2 or
more.
2. The cigarette paper according to claim 1, wherein a primary
particle of the calcium carbonate has a columnar shape or needle
shape.
3. The cigarette paper according to claim 2, wherein the primary
particle of the calcium carbonate has an average aspect ratio of
not less than 4 and less than 10 and has an average length (L) of
0.1 to 1.5 .mu.m.
4. The cigarette paper according to claim 2, wherein the secondary
particle of the calcium carbonate is in the form of a bur
shape.
5. The cigarette paper according to claim 4 having a density of 0.4
to 1.0 g/cm.sup.3.
6. The cigarette paper according to claim 1 containing a combustion
regulating agent comprising an alkali metal citrate.
7. The cigarette paper according to claim 6, containing the
combustion regulating agent in an amount of 1.0 to 5.0% by
weight.
8. A cigarette comprising: a cigarette rod including tobacco shreds
wrapped into a rod shape with the cigarette paper according to
claim 1; and a filter coaxially connected to an end of the
cigarette rod by a tipping paper.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation application of PCT
Application No. PCT/JP2012/058622, filed Mar. 30, 2012 and based
upon and claiming the benefit of priority from prior Japanese
Patent Application No. 2011-077902, filed Mar. 31, 2011, the entire
contents of all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a cigarette paper and a cigarette,
and more specifically relates to a cigarette paper and a cigarette
reducing a visible sidestream smoke amount and a carbon monoxide
amount in mainstream smoke.
[0004] 2. Description of the Related Art
[0005] Recently, a cigarette (low sidestream smoke cigarette)
having a small amount of sidestream smoke to be generated has been
developed. Whether such a cigarette actually has a small amount of
sidestream smoke to be generated is usually determined by a
so-called fishtail method (described in Health Canada Test Method
T-212). In this fishtail method, the amount of total particulate
matter in sidestream smoke is measured, and the amount of the total
particulate matter is considered as a sidestream smoke amount.
[0006] In order to provide a cigarette having a small amount of
sidestream smoke to be generated, a filler which is a compound
exhibiting combustion inhibiting effect is added to a cigarette
paper. For example, Patent Document 1 discloses that magnesium
hydroxide gel is added, and Patent Document 2 discloses that a
filler having a high-specific surface area formed of calcium
carbonate and so on is added.
[0007] Meanwhile, Patent Document 3 discloses a cigarette paper
which can reduce the sidestream smoke amount according to visual
observation (also referred to as the visible sidestream smoke
amount in this specification) rather than the sidestream smoke
amount according to the fishtail method. This cigarette paper
contains calcium carbonate in an amount of 30 g/m.sup.2 or more and
a combustion regulating agent such as potassium citrate in an
amount of 3% by weight or more.
CITATION LIST
Patent Literature
[0008] Patent Literature 1: Jpn. Pat. Appln. KOKOKU Publication No.
63-37621 [0009] Patent Literature 2: Japanese Patent No. 2730894
[0010] Patent Literature 3: Japanese Patent No. 3897700
BRIEF SUMMARY OF THE INVENTION
Technical Problem
[0011] Although the low sidestream smoke cigarette according to the
prior art significantly reduces the sidestream smoke amount, there
is a tendency to increase the carbon monoxide amount in the
mainstream smoke.
[0012] Accordingly, an object of the invention is to provide a
cigarette paper which can reduce a visible sidestream smoke amount
and at the same time can reduce a carbon monoxide amount in a
mainstream smoke.
Solution to Problem
[0013] In order to solve the above problem, this invention provides
a cigarette paper having a grammage of 40 to 55 g/m.sup.2 and
containing calcium carbonate in an amount of 18 g/m.sup.2 or
more.
[0014] This invention further provides a cigarette including a
cigarette rod including tobacco shreds wrapped into a rod shape
with the cigarette paper, and a filter coaxially connected to an
end of the cigarette rod by a tipping paper.
Advantageous Effects of Invention
[0015] A cigarette paper and a cigarette according to this
invention reduce the amount of sidestream smoke generated and the
amount of carbon monoxide in main stream smoke.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0016] FIG. 1 is a view schematically showing a typical shape of
primary particles of calcium carbonate.
[0017] FIG. 2 is a view schematically showing an example of
secondary particles having a bur shape.
[0018] FIG. 3 is a schematic perspective view showing an apparatus
which measures the amount of visible sidestream smoke of a smoking
article according to the present invention.
[0019] FIG. 4 is a block diagram schematically showing a
constitution of the apparatus which measures the amount of visible
sidestream smoke of the smoking article according to the present
invention.
[0020] FIG. 5 is a schematic diagram showing a visible sidestream
smoke amount evaluation apparatus which can be used in sensory
evaluation.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Hereinafter, the present invention will be explained in
detail.
[0022] The cigarette paper according to this invention has a
grammage of 40 to 55 g/m.sup.2 and contains calcium carbonate in an
amount of 18 g/m.sup.2 or more.
[0023] Pulp fiber used in the cigarette paper according to this
invention can be constituted of flax pulp fiber used in a typical
cigarette paper, wood pulp fiber (hardwood pulp, softwood pulp),
and so on.
[0024] The cigarette paper according to this invention is prepared
by mixing 18 g/m.sup.2 or more of calcium carbonate with the pulp
fiber. Calcium carbonate is contained in the form of particles, and
although the particle diameter can be suitably selected in terms of
cost and ease of papermaking, the particle diameter is preferably
0.02 to 10 .mu.m. The content of calcium carbonate is preferably 29
g/m.sup.2 or less. The content of calcium carbonate is more
preferably 20 to 25 g/m.sup.2. In this specification, the content
of calcium carbonate means the amount of calcium carbonate
contained in a cigarette paper after manufacture. The amount of
calcium carbonate in the cigarette paper can be obtained by
extracting and then quantifying calcium ions as described in an
example to be described later.
[0025] Calcium carbonate used in this invention is a synthetic
calcium carbonate synthesized by chemical reaction, and primary
particles of the synthetic calcium carbonate are all in
substantially the same shape and size and are homogeneous. In this
specification, the term "primary particles" refers to fundamental
particles constituting a power immediately after synthesis by
chemical reaction, and the term "secondary particles" refers to an
aggregate formed by agglomeration of a large number of primary
particles.
[0026] The shape of the primary particles of calcium carbonate to
be used is not particularly limited, and the primary particles
having any shape of a spindle shape, a cubic shape, a columnar
shape, and a needle shape can be used. However, when calcium
carbonate in which the primary particles have a columnar shape or a
needle shape is used, the amount of carbon monoxide in mainstream
smoke is significantly reduced in comparison with the case of using
calcium carbonate having another shape.
[0027] FIG. 1 shows a typical shape of a primary particle of
calcium carbonate. The primary particle shown in FIG. 1 have a
shape extending in one direction. The direction of extension of the
particle is the longitudinal direction, and the maximum value in
the longitudinal direction is referred to as the length (L). The
direction perpendicular to the longitudinal direction is the
lateral direction, and the maximum value in the lateral direction
is referred to as the width (W). The ratio of length (L) to width
(W) of the primary particle is referred to as an aspect ratio. The
ratio (aspect ratio) of the length (L) to the width (W) of the
columnar or needle-shaped primary particle is preferably not less
than 4 and less than 10. Both the columnar particle and the
needle-shaped particle refer to particles having an aspect ratio of
not less than 4 (FIG. 1). The columnar shape and the needle shape
can be distinguished by whether or not the primary particle
observed with an electron microscope has a pointed shape. Namely,
the columnar shape does not have a pointed shape (FIGS. 1(d) and
(f)), and the needle shape has a pointed shape (FIGS. 1(a) and
(c)). The needle shape may have a pointed shape at the both ends in
the extending direction of the particle or may have the pointed
shape at one end. The columnar shape includes not only a circular
cylindrical shape but also a truncated conical shape.
[0028] The width (W) and the length (L) of the primary particle can
be measured using a scanning electron microscope, for example.
[0029] In a preferred aspect, in the calcium carbonate used in this
invention, it is preferable that the primary particle has a
columnar shape or a needle shape, and, at the same time, the shape
of the secondary particle formed by agglomeration in a process of
typical papermaking has a bur shape. The bur shape represents an
agglomeration shape in which tens to thousands of primary particles
having a columnar or needle shape are three-dimensionally
entangled. As a specific example of the bur shape, there are
aspects shown in Jpn. Pat. Appln. KOKAI Publication Nos. 55-40849
and 59-94700. FIG. 2 schematically shows an example of the bur
shape. The bur shape has a central core body at its center, a large
number of primary particles may protrude from the central core
body, and the bur shape may not have the central core body at its
center. Calcium carbonate in which the secondary particles have a
bur shape is commercially available as Cal-light-SA (Shiraishi
Kogyo Kaisha, Ltd.) and bur-shaped calcium carbonate (Newlime Co.,
Ltd.), for example.
[0030] When calcium carbonate in which the secondary particles are
in the form of a bur shape is used, calcium carbonate in the form
of the primary particle (having a columnar or needle shape) may be
contained in pulp fiber, calcium carbonate in the form of the
secondary particle (having a bur shape) may be contained in the
pulp fiber, or calcium carbonate as a mixture having the forms of
the primary particle and the secondary particle may be contained in
the pulp fiber. In each case, calcium carbonate has a bur shape in
the cigarette paper.
[0031] In this invention, preferably, the primary particles of
calcium carbonate have a columnar or needle shape. More preferably,
an average aspect ratio of the primary particles falls within the
range of not less than 4 and less than 10, and an average length
(L) of the primary particles is 0.1 to 1.5 .mu.m. It is still more
preferable that the density of the obtained cigarette paper is 0.4
to 1.0 g/m.sup.3.
[0032] To obtain the average aspect ratio, representative plural
(at least 50, and for example, 50 to 200) particles are selected,
the aspect ratio is obtained by measuring the width (W) and the
length (L) of the primary particles for each particle, and an
average value of the aspect ratio is obtained, whereby the average
aspect ratio can be obtained. To obtain the average length (L),
representative plural (at least 50, and for example, 50 to 200)
particles are selected, the length (L) of each particle is
measured, and an average value of the length (L) is obtained,
whereby the average length (L) can be obtained.
[0033] The cigarette paper according to this invention has a
grammage of 40 to 55 g/m.sup.2. It is more preferable that the
grammage of the cigarette paper is 42 to 50 g/m.sup.2.
[0034] The cigarette paper according to this invention may contain
a combustion regulating agent. As the combustion regulating agent,
an alkali metal citrate is preferably used, and particularly
preferred are potassium citrate and sodium citrate, and these
combustion regulating agents may be used alone or may be used in
combination. The cigarette paper preferably contains the combustion
regulating agent in an amount of 1.0 to 5.0% by weight, and more
preferably 1.5 to 4.0% by weight.
[0035] The cigarette paper according to this invention reduces the
amount of visible sidestream smoke of a cigarette and, at the same
time, can reduce the amount of carbon monoxide in mainstream smoke
in comparison with a conventional cigarette paper.
[0036] The cigarette paper according to this invention can be used
as a cigarette paper of a cigarette with a filter. Namely,
according to one aspect of this invention, there is provided a
cigarette which includes a cigarette rod including tobacco shreds
wrapped into a rod shape with the cigarette paper of the invention
and a filter coaxially connected to an end of the cigarette rod by
a tipping paper.
[0037] The amount of carbon monoxide in mainstream smoke can be
measured as the carbon monoxide amount per smoke draft obtained by
dividing the total amount per cigarette in specified cigarette
smoking conditions (Health Canada Test Method: 55 ml/2 s) by the
total number of smoke drafts.
[0038] Although the amount of visible sidestream smoke can be
measured by sensory evaluation, the amount of visible sidestream
smoke can be simply measured using a visible sidestream smoke
amount measuring apparatus disclosed in Japanese Patent No. 3683792
(or Patent Literature 3). The visible sidestream smoke amount
measuring apparatus will be hereinafter described using FIGS. 3 and
4 (reproductions of FIGS. 1 and 2 of the Japanese Patent No.
3683792) for confirmation.
[0039] FIG. 3 is a schematic perspective view showing the visible
sidestream smoke amount measuring apparatus disclosed in the
Japanese Patent No. 3683792. FIG. 4 is a block diagram
schematically showing a configuration of the visible sidestream
smoke amount measuring apparatus.
[0040] As shown in FIGS. 3 and 4, a visible sidestream smoke amount
measuring apparatus 10 is provided with a spontaneous combustion
chamber 11 for a smoking article, a visible light emitting unit 12
used for applying a predetermined visible light beam to sidestream
smoke, generated by spontaneous combustion of the smoking article
and naturally rising (moving up) in the spontaneous combustion
chamber 1, in a direction substantially perpendicular to a
direction of a flow of the sidestream smoke, and a scattered light
intensity detection unit 14 used for detecting, as an index of the
amount of visible sidestream smoke, the intensity of scattered
light scattered by sidestream smoke in a direction substantially
perpendicular to the direction of the visible light beam.
[0041] The spontaneous combustion chamber 11 is formed of a
light-shielding material and constituted of a rectangular
parallelepiped tubular body elongated in a longitudinal direction
prescribed by four sidewalls 11a to 11d, for example. Sidewall 11a
has in its lower portion a smoking article insertion opening 111
through which a smoking article SA such as a lit cigarette is
fitted in the spontaneous combustion chamber 11. The four sidewalls
11a to 11d prescribing the spontaneous combustion chamber 11
respectively have ventilation windows 112 to 115 such as mesh
windows at their lowermost end portions so that air required for
spontaneous combustion of the smoking article SA can be supplied in
the spontaneous combustion chamber 11. It is preferable that the
position of the insertion opening 111 for a smoking article is set
to a position where sidestream smoke SSS from the smoking article
SA fitted in the spontaneous combustion chamber 11 through the
insertion opening 111 passes through the ventilation windows 112 to
115 is not affected by disturbance of outside air entering inside
the spontaneous combustion chamber 11, and a distance from the
smoking article SA to the upper end of the spontaneous combustion
chamber 11 is sufficient such that the sidestream smoke SSS is not
substantially swayed.
[0042] Glass beads (not shown) are filled in a bottom space of the
spontaneous combustion chamber 11 surrounded by the ventilation
windows 112 to 115 so that the flow of the sidestream smoke SSS
rising in the spontaneous combustion chamber 11 due to spontaneous
combustion of the smoking article is not disturbed, whereby an air
flow rectifying layer can be formed. The upper end of the
spontaneous combustion chamber 11 is opened. An exhaust hood 15 can
be installed at the open end for the purpose of exhausting in the
spontaneous combustion chamber 11. The spontaneous combustion
chamber 11 is required to be exhausted so as to avoid substantial
influence on the spontaneous combustion of the smoking article SA.
In the event of exhaust, in order to prevent the disturbance of the
flow of the sidestream smoke SSS naturally rising in the
spontaneous combustion chamber 11 due to the spontaneous combustion
of the smoking article, it is preferable that a rectification
filter 16 is attached across an upper open end of the spontaneous
combustion chamber 11.
[0043] The exhaust hood 15 has an exhaust duct 151 on its top, and
the exhaust duct 151 is connected to an exhaust system (not
shown).
[0044] The visible light emitting unit 12 is provided outside the
spontaneous combustion chamber 11. In an example shown in FIG. 3,
the visible light emitting unit 12 is provided outside sidewall 11b
facing sidewall 11a of the spontaneous combustion chamber 11 in
which the smoking article SA is inserted. A visible light
transmission window 116 is provided at a portion of sidewall 11b
facing the visible light emitting unit 12. The visible light
emitting unit 12 has a visible light source (not shown) and applies
a visible light beam VLB to the sidestream smoke SSS, generated by
the spontaneous combustion of the smoking article SA and naturally
rising in the spontaneous combustion chamber 11, in the direction
substantially perpendicular to the direction of the flow of the
sidestream smoke SSS. A visible light source is not limited
especially as long as the visible light is emitted, and although a
visible light laser, a visible light-emitting diode, a halogen
lamp, and so on can be used, for example, an A light source
specified by international commission on illumination is
representatively used.
[0045] The visible light beam (visible light flux) VLB emitted from
the visible light emitting unit 12 has a substantial
cross-sectional surface in which the visible light can be applied
to the sidestream smoke SSS naturally rising in the spontaneous
combustion chamber 11 while, even if the sidestream smoke SSS is
somewhat swayed, the sway is sufficiently covered. For example, the
visible light beam VLB has a width w (FIG. 4) in the direction
perpendicular to the irradiation direction and, at the same time,
has a rectangular cross section having a height in a direction
substantially perpendicular to the irradiation direction of the
visible light beam VLB so as to correspond to a visual field in the
sensory evaluation in consideration of a human visual field. It is
preferable that the width w is at least equal to a sway width of
the sidestream smoke SSS in the direction perpendicular to the
irradiation direction of the visible light beam. The
cross-sectional surface of the visible light beam is not limited to
a rectangular shape and may be an elliptical shape, a circular
shape, and so on. In such shaping of the visible light beam, a mask
having an opening corresponding to the cross-sectional surface of
the visible light beam may be used, or a lens system constituted of
a combination of a convex lens and a concave lens may be used, for
example, and the shaping itself can be performed by a well-known
method.
[0046] It is preferable that a light absorption unit 13 used for
absorbing/removing all light emitted from the visible light
emitting unit 12 and transmitted through the sidestream smoke SSS
so that measurement is not affected is provided outside the
spontaneous combustion chamber 11 facing the visible light emitting
unit 12 and, in the example shown in FIG. 3, provided outside
sidewall 11a. A visible light transmission window 117 is provided
at a portion of sidewall 11a facing the light absorption unit
13.
[0047] A scattered light intensity detection unit 14 is provided
outside the spontaneous combustion chamber 11 in the direction
perpendicular to the direction of the light beam emitted from the
light intensity detection unit 12, and in an example shown in FIG.
3, the scattered light intensity detection unit 14 is provided
outside sidewall 11d. A visible light transmission window 118 is
provided at a portion of sidewall 11d facing the scattered light
intensity detection unit 14. As described above, the scattered
light intensity detection unit 14 detects the intensity of
scattered light (hereinafter referred to as 90 degree scattered
light) SVL scattered in the direction substantially perpendicular
to the irradiation direction of the visible light beam VLB among
the light applied to the sidestream smoke SSS and scattered by the
sidestream smoke SSS. The scattered light intensity detection unit
14 is provided in itself with a well-known optical system (not
shown) used for collecting the 90 degree scattered light SVL and
has a photoelectric converter (not shown) which converts the
collected 90 degree scattered light SVL into an electrical signal
and outputs the electrical signal. As the photoelectric converter,
a photomultiplier which converts light into a voltage signal can be
preferably used. The converted voltage signal is subjected to
analog-to-digital conversion, for example, and then can be
subjected to data sampling with a personal computer. Data
acquisition interval and acquisition time can be arbitrarily set,
and typically measurement at 300 points can be performed at an
interval of 0.2 seconds for 1 minute.
[0048] The detected intensity of the 90 degree scattered light SVL
correlates very well with the amount of visible sidestream smoke,
and as the detected intensity of the 90 degree scattered light is
large, it can be determined that the amount of visible sidestream
smoke is relatively large. It was shown that the intensity of the
90 degree scattered light does not correlate with the total amount
of particulate matter in the sidestream smoke.
[0049] It is preferable to install external stray light shielding
boxes 17 to 19 between the visible light emitting unit 12 and the
visible light transmission window 116, between the light absorbing
unit 13 and the visible light transmission window 117, and between
the scattered light intensity detection unit 14 and the visible
light transmission window 118 in order to prevent external stray
light from entering through each visible light transmission
window.
[0050] When a representative example of the entire size of an
apparatus 10 and so on are shown, the spontaneous combustion
chamber 11 has a rectangular solid shape of 11 cm.times.11 cm
having a height of 80 cm, and the smoking article insertion opening
111 is provided at a position of 50 cm from the lower end of the
spontaneous combustion chamber 11, a distance from the smoking
article SA to the center of visible light beam is 10 cm, and the
visible light beam emitted from the visible light emitting unit has
a cross section with a size of 5 cm.times.5 cm.
[0051] As shown in FIG. 4, the visible sidestream smoke amount
measuring apparatus preferably has conversion table means 20 that
converts the 90 degree scattered light intensity detected by the
scattered light intensity detection unit 14 into the amount of
visible sidestream smoke and outputs the amount of visible
sidestream smoke based on a correlative relationship between the 90
degree scattered light intensity and the amount of visible
sidestream smoke. In the conversion table means, the correlative
relationship between the 90 degree scattered light intensity
obtained in advance and the amount of visible sidestream smoke is
input as a conversion equation, a calibration curve, and so on, a
90 degree scattered light intensity signal output from the
scattered light intensity detection unit 14 is converted into the
amount of visible sidestream smoke, and the amount of visible
sidestream smoke is output. In order to obtain the correlative
relationship between the 90 degree scattered light intensity and
the amount of visible sidestream smoke, the amount of visible
sidestream smoke of the smoking articles such as a large number of
cigarettes is first evaluated by sensory evaluation according to a
two-point comparison method, and the amount of visible sidestream
smoke is converted into a number. The 90 degree scattered light
intensity of the same smoking article detected by this apparatus is
measured. For example, when the vertical axis represents the amount
of visible sidestream smoke and the horizontal axis represents the
90 degree scattered light intensity, the calibration curve can be
obtained by plotting obtained measured values. The conversion
equation from the 90 degree scattered light intensity to the amount
of visible sidestream smoke can be obtained based on the
calibration curve.
[0052] The sensory evaluation according to the two-point comparison
method can be performed using a visible sidestream smoke amount
evaluation apparatus shown in FIG. 5, for example. Namely, a
standard cigarette CIG1 and a target cigarette CIG2 are
spontaneously combusted in two bilaterally symmetric spontaneous
combustion chambers 31 and 32, and there is employed such a
questionnaire that with respect to the standard cigarette CIG1
having 5 points, how much the amount of sidestream smoke of the
target cigarette CIG2 is observed within a range of 0 to 10 points.
The chambers 31 and 32 are provided respectively with observation
windows 311 and 321 having a fixed longitudinal width, and visible
light sources 33 and 34 are provided in the upper portions of the
respective chambers. Preferably, each longitudinal width of the
observation windows 311 and 321 corresponds to the height of the
visible light beam emitted from the visible light emitting unit 12
of the visible sidestream smoke amount measuring apparatus, and the
distance from the cigarettes CIG1 and CIG2 to the lower ends of the
observation windows 311 and 321 corresponds to a distance from the
smoking article SA at the lower end of the visible light beam
emitted from the visible light emitting unit 12 of the visible
sidestream smoke amount measuring apparatus. The visible light from
the visible light sources 33 and 34 is applied from above to the
sidestream smokes SS1 and SS2, and the sidestream smokes SS1 and
SS2 are observed only from the observation windows 311 and 321.
[0053] The 90 degree scattered light intensity obtained by the
visible sidestream smoke amount measuring apparatus correlates very
well with amount of the visible sidestream smoke in the sensory
evaluation, and this fact is demonstrated in Japanese Patent No.
3897700. In this invention, when the sensory evaluation according
to the two-point comparison method is performed using the visible
sidestream smoke amount evaluating apparatus shown in FIG. 5, it is
confirmed that when a value of visible sidestream smoke amount/SBR
(hereinafter referred to as the amount of visible sidestream smoke)
shown as an index in this example is not more than
5.0.times.10.sup.-2 (min/mm), it can be determined that the amount
of visible sidestream smoke according to the sensory evaluation is
sufficiently reduced with respect to a standard typical
cigarette.
EXAMPLES
[0054] Hereinafter, the invention will be described with reference
to examples. In the following examples, calcium carbonate PCX-850
and Cal-light-SA were purchased from Shiraishi Kogyo Kaisha, Ltd.,
and needle-shaped calcium carbonate and bur-shaped calcium
carbonate were purchased from Newlime Co., Ltd.
[0055] The primary particle of PCX-850 has a spindle shape, and
although the primary particles form the secondary particle, a bur
shape is not formed. The primary particle of Cal-light-SA has a
columnar shape, and the primary particles are agglomerated to form
a bur-shaped secondary particles. The primary particle of the
needle-shaped calcium carbonate has a needle shape, and the primary
particles does not form the secondary particle. The primary
particle of bur-shaped calcium carbonate has a needle shape, and
the primary particles are agglomerated to form the bur-shaped
secondary particle.
Comparative Examples 1 to 3, Examples 1 to 4, and Reference
Examples
[0056] A pulp mixture in which the weight ratio of bleached broad
leaf tree kraft pulp (LBKP) to bleached coniferous tree kraft pulp
(NBKP) is 8:2 is beaten so that a freeness is about 100 mL in
Canadian Standard Freeness, and calcium carbonate shown in Table 1
as a filler is added to the beaten pulp mixture in a content shown
in Table 1. With the use of an obtained paper stock, a cigarette
paper (the grammage is shown in Table 1) is subjected to
papermaking by a TAPPI standard sheet machine. Potassium citrate
aqueous solution as a combustion regulating agent is coated onto a
surface of the obtained cigarette paper so that potassium citrate
in an amount of 3 to 4 wt % on the dry base is contained in the
cigarette paper. This cigarette paper is matched for two or more
days under conditions of a temperature of 22.degree. C. and a
relative humidity of 60% and cut into a predetermined length. In
the amount of calcium carbonate in the cigarette paper, ultrasonic
extraction is performed for 30 minutes in 0.3 N aqueous
hydrochloric acid, and calcium carbonate is quantified as calcium
ions by a capillary electrophoresis system (7100) manufactured by
Agilent Technologies, and calcium ions are converted into calcium
carbonate, whereby the amount of calcium carbonate in the cigarette
paper is obtained.
[0057] With the use of the obtained cigarette paper and tobacco
shreds (American blend), a cigarette is produced by a tobacco
roller (Rizla). As the size of the cigarette, the circumference is
22.6 mm, and the length is 67 mm. A normal filter (having a length
of 31 mm) is provided to be mounted on one end of the cigarette
with the use of a tipping paper. The filling amount of the tobacco
shreds is 0.515 g per cigarette.
[0058] The amount of visible sidestream smoke of the obtained
cigarette is measured using an apparatus shown in FIGS. 3 and 4,
the amount of carbon monoxide in mainstream smoke is measured using
a Micro-GC (3000A) manufactured by Agilent Technologies, and the
amount of carbon monoxide per smoke (puff) is calculated.
[0059] In the measurement of the amount of visible sidestream
smoke, in order to correct the difference between days in
sensitivity of a visible laser, for each measurement, the amount of
visible sidestream smoke of each cigarette is standardized with a
visible sidestream smoke amount measured value in a standard
cigarette (reference cigarette 3R4F) (accordingly, the unit is
nondimensional). In order to eliminate influence of the grammage of
the cigarette paper and the kind and content of calcium carbonate,
the standardized amount of visible sidestream smoke is divided by
the spontaneous combustion rate (SBR) (unit: mm/min) of a
cigarette. SBR is measured at an atmosphere linear velocity of 200
mm/s. The results are indicated in Table 1.
[0060] The reference example is an example of using calcium
carbonate (Unibur-70) (although it is not available now, it is
stored by the present applicant) described in Jpn. Pat. Appln.
KOKAI Publication No. 59-94700.
TABLE-US-00001 TABLE 1 Cigarette Visible Cigarette paper sidestream
CO Calcium Cigarette smoke amount in carbonate paper amount/
mainstream Content grammage SBR smoke Examples Kind (g/m.sup.2)
(g/m.sup.2) (min/mm) (mg/puff) Comparative PCX-850 11.0 43.6 7.3
.times. 10.sup.-2 4.6 Example 1 Comparative 15.0 45.0 6.8 .times.
10.sup.-2 4.5 Example 2 Example 1 18.8 47.0 4.7 .times. 10.sup.-2
4.3 Example 2 23.5 47.1 4.4 .times. 10.sup.-2 3.4 Example 3 28.0
47.2 4.8 .times. 10.sup.-2 3.9 Example 4 25.0 53.0 4.8 .times.
10.sup.-2 4.1 Comparative 30.0 63.0 3.3 .times. 10.sup.-2 5.0
Example 3 Reference Unibur-70 10.5 27.5 7.8 .times. 10.sup.-2 3.3
Example
[0061] As can be seen in the result shown in Table 1, it is
confirmed that if the content of calcium carbonate is not less than
18 g/m.sup.2, the value of the visible sidestream smoke amount per
spontaneous combustion rate (SBR) is less than 5.0.times.10.sup.-2.
This fact shows that the visible sidestream smoke is sufficiently
reduced (examples 1 to 4). Meanwhile, It will be shown that when
the amount of calcium carbonate is less than 18 g/m.sup.2,
including the reference example, the amount of visible sidestream
smoke is large (comparative examples 1 and 2).
[0062] Although the yield of calcium carbonate with respect to the
amount of pulp in the cigarette paper depends on the amount of
pulp, it is considered that the maximum value is 40 to 60%, and
when the yield is 40 to 50%, the grammage of the cigarette paper
required for maintaining not less than 18 g/m.sup.2 of calcium
carbonate is assumed to be not less than 40 g/m.sup.2. When the
content of calcium carbonate is further increased, the grammage is
required to be increased, and accompanying this, the amount of
carbon monoxide in the sidestream smoke is increased. Specifically,
it can be confirmed from the comparative example 3, that when the
grammage is more than 55 g/m.sup.2, although there is a tendency to
reduce the amount of visible sidestream smoke, the amount of carbon
monoxide in the mainstream smoke is increased.
[0063] According to above, when the cigarette paper has a grammage
of 40 to 55 g/m.sup.2 and contains calcium carbonate in an amount
of not less than 18 g/m.sup.2, the amount of sidestream smoke
generated and the amount of carbon monoxide in the mainstream smoke
can be reduced. As shown in the comparative example 2, when the
cigarette paper has a grammage of 42 to 50 g/m.sup.2 and contains
calcium carbonate in an amount of 20 to 25 g/m.sup.2, it is
possible to expect greater effects.
Examples 5 and 6
[0064] In the examples 5 and 6, in calcium carbonate in which the
primary particles have comparable length (L) and the shapes of the
primary particles are different, the influence of the shape of the
primary particles on the amount of visible sidestream smoke and the
mainstream smoke is examined. As calcium carbonate in which the
primary particles have different shapes, PCX-850 and Cal-light-SA
are used. The contents of PCX-850 and Cal-light-SA are 22.5 and
23.0 g/m.sup.2, respectively.
[0065] A cigarette paper is manufactured as in the above examples
to produce a cigarette except that the grammage of the cigarette
paper and the kind of calcium carbonate are changed as shown in the
following Table 2. The amount of visible sidestream smoke and the
amount of carbon monoxide in the main stream smoke of the obtained
cigarette are measured. Further, with regard to the obtained
cigarette paper, in order to examine a mechanism in which the
amount of carbon monoxide in the main stream smoke is reduced, the
density of the cigarette paper is measured. The results are shown
in Table 2.
[0066] The length (L) of the primary particle described in Table 2
is an average of the length (L) of 100 primary particles measured
by means of Winroof image analysis software (Mitani Corporation)
using an SEM image captured with a JSM-5310 scanning electron
microscope manufactured by JEOL. Although the aspect ratio of
calcium carbonate used in this example is indicated in Table 2, the
width (W) of the primary particle is measured in a similar manner
to the length (L) of the primary particle, and the ratio (L/W) of
the length (L) of the primary particle to the width (W) is
calculated.
TABLE-US-00002 TABLE 2 Cigarette paper Cigarette Calcium carbonate
Cigarette Cigarette Visible Shape of Primary Average paper paper CO
amount in sidestream primary particle average aspect grammage
density mainstream smoke amount/SBR Examples Kind particle length
(L) (.mu.m) ratio (g/m.sup.2) (g/cm.sup.3) smoke (mg/puff) (min/mm)
Example 5 PCX-850 Spindle 1.00* 3.5 46.4 0.65 3.5 4.4 .times.
10.sup.-2 Example 6 Cal-light-SA Columnar 1.21 9.5 45.1 0.52 3.0
4.8 .times. 10.sup.-2 *Shiraishi Kogyo Kaisha, Ltd. Nominal value
(long diameter) is described
[0067] As can be seen in the result shown in Table 2, when the
calcium carbonate in which the primary particles have a columnar
shape and the calcium carbonate in which the primary particles have
a spindle shape are compared with each other, the amount of carbon
monoxide in the main stream smoke of the cigarette paper using the
columnar calcium carbonate is lower, and therefore, it is confirmed
that the shape of the primary particle is important. With regard to
the density of the cigarette paper, in comparison with the
cigarette paper using the calcium carbonate in which the primary
particles have a spindle shape, when the calcium carbonate in which
the primary particles have a columnar shape is used, the reduction
of the cigarette paper density can be confirmed. When the calcium
carbonate (Cal-light-SA) in which the primary particles have a
columnar shape is used, it is assumed that the density of the
cigarette paper is reduced, so that the amount of carbon monoxide
in the mainstream smoke is reduced. When a limitation in
manufacturing at present is considered, a suitable aspect ratio
(L/W) of the columnar or needle-shaped calcium carbonate is
preferably not less than 4 and less than 10. When Cal-light-SA is
used, the visible sidestream smoke falls within a range of not more
than 5.0.times.10.sup.-2 (min/mm), and therefore, it can be said
that the amount of visible sidestream smoke can be sufficiently
reduced.
Examples 7 and 8
[0068] Next, in calcium carbonate in which the secondary particles
similarly have a bur shape, the influence of the length (L) of the
primary particle on the amount of visible sidestream smoke and the
amount of carbon monoxide in the mainstream smoke is examined. As
calcium carbonate having columnar or needle-shaped primary
particles having different length (L), bur-shaped calcium carbonate
and Cal-light-SA are used.
[0069] A cigarette paper is manufactured as in the above examples
to produce a cigarette except that the grammage of the cigarette
paper and the kind of calcium carbonate are changed as shown in the
following Table 3. The amount of visible sidestream smoke and the
amount of carbon monoxide in the main stream smoke of the obtained
cigarette are measured. The results are indicated in Table 3. The
length (L) of the primary particle described in Table 3 is an
average of the length (L) of 100 primary particles measured
according to the above method. The primary particles of bur-shaped
calcium carbonate have an average aspect ratio of 6.7, and the
primary particles of Cal-light-SA have an average aspect ratio of
9.5.
TABLE-US-00003 TABLE 3 Cigarette paper Cigarette Calcium carbonate
Cigarette Visible Shape of Primary paper CO amount in sidestream
primary particle average Content grammage mainstream smoke
amount/SBR Examples Trade name particle length (L) (.mu.m)
(g/m.sup.2) (g/m.sup.2) smoke (mg/puff) (min/mm) Example 7
Bur-shaped Needle-shaped 3.30 23.4 49.2 4.1 3.2 .times. 10.sup.-2
calcium carbonate Example 8 Cal-light-SA Columnar 1.21 23.6 48.1
3.2 3.0 .times. 10.sup.-2
[0070] As can be seen in the result shown in Table 3, in the
cigarette paper using two kinds of calcium carbonate in which the
secondary particles similarly have a bur shape, it is confirmed
that the amount of carbon monoxide in the main stream smoke in the
cigarette paper using Cal-light-SA in which the length (L) of the
primary particles is small is further reduced. Thus, it can be
shown that the smaller the size of the primary particle, the larger
the effect of reducing the amount of carbon monoxide in the
mainstream smoke, and considering variation of the length (L) of
the primary particles, it is assumed that the average length (L) of
the primary particles is preferably not more than 1.5 .mu.m.
Examples 9 and 10
[0071] The influence of whether or not the secondary particles of
calcium carbonate are in the form of a bur shape on the amount of
visible sidestream smoke and the amount of carbon monoxide in the
mainstream smoke is examined.
[0072] A cigarette paper is manufactured as in the above examples
to produce a cigarette except that the grammage of the cigarette
paper and the kind of calcium carbonate are changed as shown in the
following Table 4. The amount of visible sidestream smoke and the
amount of carbon monoxide in the mainstream smoke of the obtained
cigarette are measured. The results are indicated in Table 4. In
the bur-shaped calcium carbonate used here, the primary particles
have a needle shape, the average length (L) of the primary
particles is 3.3 .mu.m, the average aspect ratio of the primary
particles is 8.0, and the secondary particles have a bur shape.
Meanwhile, in the needle-shaped calcium carbonate, the primary
particles have a needle shape, the average length (L) of the
primary particles is 4.8 .mu.m, and the average aspect ratio of the
primary particles is 6.7; however, the secondary particles does not
have a bur shape. Thus, the bur-shaped calcium carbonate and the
needle-shaped calcium carbonate in which the values of the lengths
(L) of the primary particles are approximately close to each other
are compared, whereby the influence of whether or not the secondary
particles are in the form of a bur shape on the amount of visible
sidestream smoke and the amount of carbon monoxide in the
mainstream smoke can be verified.
TABLE-US-00004 TABLE 4 Cigarette paper Cigarette Calcium carbonate
Cigarette Visible Shape of Bur shape paper CO amount in sidestream
primary of secondary Content grammage mainstream smoke amount/SBR
Examples Trade name particle particle (g/m.sup.2) (g/m.sup.2) smoke
(mg/puff) (min/mm) Example 9 Needle-shaped Needle-shape Without
24.5 49.8 4.7 3.7 .times. 10.sup.-2 calcium carbonate Example 10
Bur-shaped Needle-shape With 23.5 48.6 4.0 3.5 .times. 10.sup.-2
calcium carbonate
[0073] As can be seen in the result shown in Table 4, in the
cigarette paper using bur-shaped calcium carbonate in which the
secondary particles have a bur shape, although the amount of
visible sidestream smoke is substantially equivalent in comparison
with the cigarette paper using needle-shaped calcium carbonate, the
amount of carbon monoxide in the mainstream smoke is reduced. From
this fact, the effect obtained when the calcium carbonate in which
the secondary particles have a bur shape is used is confirmed.
However, in the cigarette paper containing calcium carbonate in
which the primary particles have a large length (L), since the
density of the cigarette paper is not reduced, the effect of
reducing the amount of carbon monoxide in the mainstream smoke can
be less expected, and as the length (L) of the primary particles
becomes small, the higher the carbon monoxide reduction effect that
can be expected. Namely, in the cigarette paper using calcium
carbonate in which the primary particles have a columnar shape or
needle shape, the size of the primary particles is small, and the
secondary particles have a bur shape, it is guessed that the
density of the cigarette paper is reduced most, and the carbon
monoxide amount in the mainstream smoke is reduced most.
[0074] In this example, although a cigarette having a circumference
of 22.6 mm is used, a similar effect can be expected in a cigarette
having a different circumference, and the invention does not limit
the size of a cigarette.
* * * * *